U.S. patent application number 13/455275 was filed with the patent office on 2012-11-15 for chemical compounds 785.
This patent application is currently assigned to ASTRAZENECA AB. Invention is credited to Alan Martin Birch, Roger John Butlin, Leonie Campbell, Clive Green, Andrew Leach, Paul Michael Murray, Per Olof Ryberg, Michael James Waring.
Application Number | 20120289520 13/455275 |
Document ID | / |
Family ID | 42357808 |
Filed Date | 2012-11-15 |
United States Patent
Application |
20120289520 |
Kind Code |
A1 |
Birch; Alan Martin ; et
al. |
November 15, 2012 |
CHEMICAL COMPOUNDS 785
Abstract
DGAT-1 inhibitor compounds of formula (I),
pharmaceutically-acceptable salts and pro-drugs thereof are
described, together with pharmaceutical compositions, processes for
making them and their use in treating, for example, obesity
##STR00001##
Inventors: |
Birch; Alan Martin;
(Macclesfield, GB) ; Butlin; Roger John;
(Macclesfield, GB) ; Campbell; Leonie;
(Macclesfield, GB) ; Green; Clive; (Macclesfield,
GB) ; Leach; Andrew; (Macclesfield, GB) ;
Waring; Michael James; (Macclesfield, GB) ; Murray;
Paul Michael; (Macclesfield, GB) ; Ryberg; Per
Olof; (Sodertalje, SE) |
Assignee: |
ASTRAZENECA AB
Sodertalje
SE
|
Family ID: |
42357808 |
Appl. No.: |
13/455275 |
Filed: |
April 25, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12818187 |
Jun 18, 2010 |
8188092 |
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13455275 |
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61218539 |
Jun 19, 2009 |
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Current U.S.
Class: |
514/255.05 ;
514/255.06; 544/405; 544/406 |
Current CPC
Class: |
A61P 3/00 20180101; C07D
401/12 20130101; A61P 3/10 20180101; A61P 3/04 20180101; A61P 43/00
20180101; C07D 241/24 20130101; C07D 413/10 20130101 |
Class at
Publication: |
514/255.05 ;
544/406; 514/255.06; 544/405 |
International
Class: |
C07D 241/24 20060101
C07D241/24; A61P 3/04 20060101 A61P003/04; C07D 413/10 20060101
C07D413/10; A61P 3/10 20060101 A61P003/10; A61K 31/4965 20060101
A61K031/4965; A61K 31/497 20060101 A61K031/497 |
Claims
1. A compound of formula (I), or a pharmaceutically-acceptable salt
thereof, ##STR00152## wherein each r is independently 0 or 1 and
each X.sub.1 is independently selected from linear (1-3C)alkyl,
(2-3C)alkenyl, (2-3C)alkynyl, (1-2C)alkoxy, methoxymethyl, amino
and cyano; each q is independently 0 or 1 and each X.sub.2 is
independently selected from fluoro, chloro, bromo, amino, cyano,
(1-3C)alkyl, (2-3C)alkenyl, (2-3C)alkynyl and (1-2C)alkoxy; Y.sub.1
is selected from fluoro, chloro, bromo, cyano, (1-3C)alkyl and
(1-2C)alkoxy; n is 0, 1 or 2 and each Y.sub.2 is independently
selected from fluoro, chloro, bromo, cyano, hydroxy, (1-3C)alkyl
and (1-2C)alkoxy; p is 0, 1 or 2 and each Y.sub.3 is independently
(1-3C)alkyl or when p is 2 each Y.sub.3 may also link to form a
(3-5C)cycloalkyl ring; Z is carboxy or a group Q selected from
--CONHSO.sub.2Me or one of the following rings, ##STR00153## or Z
is --CONRbRc wherein Rb and Rc are independently selected from
hydrogen, (1-4C)alkyl and (1-4C)alkoxyethyl or Rb and Rc are linked
so as to form a morpholine ring or a (4-6C)heterocyclic ring, and
when Z is --CONRbRc the (1-4C)alkyl group and morpholine or
(4-6C)heterocyclic rings that may be formed may be optionally
substituted on an available carbon atom by carboxy or a group Q;
and wherein any carbon atom in a linear (1-3C)alkyl, (1-3C)alkyl or
(1-2C)alkoxy containing group defined above may be optionally
substituted by up to 3 fluoro atoms.
2. A compound of formula (I), or a pharmaceutically-acceptable
salt, thereof, as claimed in claim 1, wherein both r are 1 and each
X.sub.1 is linear (1-3C)alkyl.
3. A compound as claimed in claim 1, or a
pharmaceutically-acceptable salt, thereof, wherein Z is carboxy,
--CONRbRc or a group ##STR00154##
4. A compound as claimed in claim 1, or a
pharmaceutically-acceptable salt, thereof, wherein Z is
carboxy.
5. A compound as claimed in claim 1, or a
pharmaceutically-acceptable salt, thereof, wherein Y.sub.1 is
chloro, fluororo or methyl.
6. A compound as claimed in claim 1, or a
pharmaceutically-acceptable salt, thereof, wherein Y.sub.1 is
chloro.
7. A compound as claimed in claim 1, or a
pharmaceutically-acceptable salt, thereof, wherein q is 0.
8. A compound as claimed in claim 1, or a
pharmaceutically-acceptable salt, thereof, wherein q is 1 and
X.sub.2 is chloro or fluoro.
9. A compound as claimed in claim 1, or a
pharmaceutically-acceptable salt, thereof, wherein p is 1 and
Y.sub.3 is methyl.
10. A compound as claimed in claim 1, or a
pharmaceutically-acceptable salt, thereof, wherein p is 2 each
Y.sub.3 link to form a (3-5C)cycloalkyl ring;
11. A pharmaceutical composition which comprises a compound of
formula (I) as claimed in claim 1), or a
pharmaceutically-acceptable salt, thereof, in association with a
pharmaceutically-acceptable excipient or carrier.
12. (canceled)
13. A method for producing an inhibition of DGAT1 activity in a
warm-blooded animal, such as a human being, in need of such
treatment which comprises administering to said animal an effective
amount of a compound of formula (I) as claimed in claim 1, or a
pharmaceutically-acceptable salt thereof.
14. A method of treating diabetes mellitus and/or obesity in a
warm-blooded animal, such as a human being, in need of such
treatment which comprises administering to said animal an effective
amount of a compound of formula (I) as claimed in claim 1, or a
pharmaceutically-acceptable salt, thereof.
15. A process for preparing a compound of Formula (I) as defined in
claim 1 which process comprises (a) Suzuki coupling of a pyrazine
derivative (IV), wherein X is a leaving group, with a substituted
intermediate boron-containing compound of formula (II) wherein E is
a boronic acid or derivative thereof: ##STR00155## (b) Suzuki
coupling of a pyrazine ester (III), wherein P is a protecting group
and X is a leaving group, with a substituted intermediate
boron-containing compound of formula (II), wherein E is a boronic
acid or derivative thereof, followed by removal of the protecting
group and conversion to the corresponding primary carboxamide:
##STR00156## (c) Suzuki coupling of a phenyl derivative (V-B1),
wherein X is a leaving group, with a substituted pyrazine
intermediate boron-containing compound of formula (V) wherein E is
a boronic acid or derivative thereof: ##STR00157## (d) Suzuki
coupling of a pyrazine derivative (V-A1), wherein X is a leaving
group, with a substituted phenyl intermediate boron-containing
compound of formula (VI) wherein E is a boronic acid or derivative
thereof: ##STR00158## (e) chiral compounds of the invention,
wherein p=1, Y.sub.3 is methyl and Z is carboxy, can be prepared by
chiral reduction of an alpha methylene acid intermediate (VII) by
catalytic hydrogentation to form a compound of formula (I):
##STR00159## and thereafter if necessary: i) converting a compound
of Formula (I) into another compound of Formula (I); ii) removing
any protecting groups; iii) forming a pharmaceutically acceptable
salt.
Description
[0001] This application claims the benefit under 35 U.S.C.
.sctn.119(e) of Application No. 61/218,539 (US) filed on Jun. 19,
2009.
[0002] The present invention relates to compounds which inhibit
acetyl CoA(acetyl coenzyme A): diacylglycerol acyltransferase
(DGAT1) activity, processes for their preparation, pharmaceutical
compositions containing them as the active ingredient, methods for
the treatment of disease states associated with DGAT1 activity, to
their use as medicaments and to their use in the manufacture of
medicaments for use in the inhibition of DGAT1 in warm-blooded
animals such as humans. In particular this invention relates to
compounds useful for the treatment of type II diabetes, insulin
resistance, impaired glucose tolerance and obesity in warm-blooded
animals such as humans, more particularly to the use of these
compounds in the manufacture of medicaments for use in the
treatment of type II diabetes, insulin resistance, impaired glucose
tolerance and obesity in warm-blooded animals such as humans.
[0003] Acyl CoA:diacylglycerol acyltransferase (DGAT) is found in
the microsomal fraction of cells. It catalyzes the final reaction
in the glycerol phosphate pathway, considered to be the main
pathway of triglyceride synthesis in cells by facilitating the
joining of a diacylglycerol with a fatty acyl CoA, resulting in the
formation of triglyceride. Although it is unclear whether DGAT is
rate-limiting for triglyceride synthesis, it catalyzes the only
step in the pathway that is committed to producing this type of
molecule [Lehner & Kuksis (1996) Biosynthesis of
triacylglycerols. Prog. Lipid Res. 35: 169-201].
[0004] Two DGAT genes have been cloned and characterised (DGAT1 and
DGAT2). Both of the encoded proteins catalyse the same reaction
although they share no sequence homology. The DGAT1 gene was
identified from sequence database searches because of its
similarity to acyl CoA:cholesterol acyltransferase (ACAT) genes.
[Cases et al (1998) Identification of a gene encoding an acyl
CoA:diacylglycerol acyltransferase, a key enzyme in triacylglycerol
synthesis. Proc. Natl. Acad. Sci. USA 95: 13018-13023]. DGAT1
activity has been found in many mammalian tissues, including
adipocytes.
[0005] Because of the previous lack of molecular probes, little is
known about the regulation of DGAT1. DGAT1 is known to be
significantly up-regulated during adipocyte differentiation.
[0006] Studies in gene knockout mice have indicated that modulators
of the activity of DGAT1 would be of value in the treatment of type
II diabetes and obesity. DGAT1 knockout (Dgat1.sup.-/-) mice, are
viable and capable of synthesizing triglycerides, as evidenced by
normal fasting serum triglyceride levels and normal adipose tissue
composition. Dgat1.sup.-/- mice have less adipose tissue than
wild-type mice at baseline and are resistant to diet-induced
obesity. Metabolic rate is .about.20% higher in Dgat1.sup.-/- mice
than in wild-type mice on both regular and high-fat diets [Smith et
al (2000) Obesity resistance and multiple mechanisms of
triglyceride synthesis in mice lacking DGAT. Nature Genetics 25:
87-90]. Increased physical activity in Dgat1.sup.-/- mice partially
accounts for their increased energy expenditure. The Dgat1.sup.-/-
mice also exhibit increased insulin sensitivity and a 20% increase
in glucose disposal rate. Leptin levels are 50% decreased in the
Dgat1.sup.-/- mice in line with the 50% decrease in fat mass.
[0007] When Dgat1.sup.-/- mice are crossed with ob/ob mice, these
mice exhibit the ob/ob phenotype [Chen et al (2002) Increased
insulin and leptin sensitivity in mice lacking acyl
CoA:diacylglycerol acyltransferase J. Clin. Invest. 109:1049-1055]
indicating that the Dgat1.sup.-/- phenotype requires an intact
leptin pathway. When Dgat1.sup.-/- mice are crossed with Agouti
mice a decrease in body weight is seen with normal glucose levels
and 70% reduced insulin levels compared to wild type, agouti or
ob/ob/Dgat1.sup.-/- mice.
[0008] Transplantation of adipose tissue from Dgat1.sup.-/- mice to
wild type mice confers resistance to diet-induced obesity and
improved glucose metabolism in these mice [Chen et al (2003)
Obesity resistance and enhanced glucose metabolism in mice
transplanted with white adipose tissue lacking acyl
CoA:diacylglycerol acyltransferase J. Clin. Invest. 111:
1715-1722].
[0009] Various International Applications disclose compounds which
inhibit DGAT-1, for example WO 2006/064189 describes certain
oxadiazole compounds which inhibit DGAT-1. However, there remains a
need for further DGAT-1 inhibitors possessing desirable properties,
such as, for example, pharmaco-kinetic/dynamic and/or
physico-chemical and/or toxicological profiles.
[0010] Accordingly, the present invention provides a compound of
formula (I), or a pharmaceutically-acceptable salt, or pro-drug
thereof,
##STR00002##
wherein each r is independently 0 or 1 and each X.sub.1 is
independently selected from linear (1-3C)alkyl, (2-3C)alkenyl,
(2-3C)alkynyl, (1-2C)alkoxy, methoxymethyl, amino and cyano; each q
is independently 0 or 1 and each X.sub.2 is independently selected
from fluoro, chloro, bromo, amino, cyano, (1-3C)alkyl,
(2-3C)alkenyl, (2-3C)alkynyl and (1-2C)alkoxy; Y.sub.1 is selected
from fluoro, chloro, bromo, cyano, (1-3C)alkyl and (1-2C)alkoxy; n
is 0, 1 or 2 and each Y.sub.2 is independently selected from
fluoro, chloro, bromo, cyano, hydroxy, (1-3C)alkyl and
(1-2C)alkoxy; p is 0, 1 or 2 and each Y.sub.3 is independently
(1-3C)alkyl or when p is 2 each Y.sub.3 may also link to form a
(3-5C)cycloalkyl ring; Z is carboxy or a group Q selected from
--CONHSO.sub.2Me or one of the following rings,
##STR00003##
or Z is --CONRbRc wherein Rb and Rc are independently selected from
hydrogen, (1-4C)alkyl and (1-4C)alkoxyethyl or Rb and Rc are linked
so as to form a morpholine ring or a (4-6C)heterocyclic ring, and
when Z is --CONRbRc the (1-4C)alkyl group and morpholine or
(4-6C)heterocyclic rings that may be formed may be optionally
substituted on an available carbon atom by carboxy or a group Q;
and wherein any carbon atom in a linear (1-3C)alkyl, (1-3C)alkyl or
(1-2C)alkoxy containing group defined above may be optionally
substituted by up to 3 fluoro atoms.
[0011] For the avoidance of doubt when p=2 the group
##STR00004##
denotes the group
##STR00005##
and
[0012] when p=0. the group
##STR00006##
denotes the group
##STR00007##
[0013] A further feature is any of the claims or embodiments herein
with the proviso that any of the specific Examples herein, or a
pharmaceutically-acceptable salt of any of these, are individually
disclaimed.
[0014] A further feature of the invention is a compound of formula
(I) comprising a carboxylic acid mimic or bioisosteres of the group
Z. As used herein, the reference to carboxylic acid mimic or
bioisostere includes groups as defined in The Practice of Medicinal
Chemistry, Wermuth C. G. Ed.: Academic Press: New York, 1996, p 203
which is incorporated herein by reference. Particular examples of
such groups include --SO.sub.3H, --S(O).sub.2NHR.sup.13,
S(O).sub.2NHC(O)R.sup.13, --CH.sub.2S(O).sub.2R.sup.13,
--C(O)NHS(O).sub.2R.sup.13, --C(O)NHOH, --C(O)NHCN,
--CH(CF.sub.3)OH, C(CF.sub.3).sub.2OH, --P(O)(OH).sub.2 and groups
of sub-formula (a)-(i') below
##STR00008## ##STR00009## ##STR00010## ##STR00011##
where p in sub-formula (k) is 1 or 2, R.sup.27 and R.sup.28 are
independently selected from hydrogen, hydroxy, (1-6C)alkoxy, thiol,
(1-6C)alkylthio, --C(O)R.sup.29, --S(O)R.sup.30,
--SO.sub.2R.sup.31, --NR.sup.32R.sup.33, --NHCN, halogen and
trihalomethyl, where R.sup.29, R.sup.30 and R.sup.31 are
--OR.sup.34, (1-6C)alkyl, --NR.sup.32R.sup.33 or trihalomethyl,
R.sup.32 and R.sup.33 are independently selected from hydrogen,
(1-6C)alkyl, --SO.sub.2R.sup.34 and --COR.sup.35, where R.sup.35 is
(1-6C)alkyl or trihalomethyl, and R.sup.34 is hydrogen, (1-6C)alkyl
or trihalomethyl and R.sup.13 is selected from hydrogen,
(1-6C)alkyl, hydroxy, halo, amino, cyano, ((1-3C)alkyl)CONH--,
carboxy, (1-6C)alkoxy, (1-6C)alkoxycarbonyl, carbamoyl,
N-((1-6C)alkyl)carbamoyl, halo((1-6C)alkyl) (such as
trifluoromethyl), (1-6C)alkylsulphonyl or (1-6C)alkylsulphinyl.
Particular examples of R.sup.27 or R.sup.28 are hydroxy.
[0015] Particular carboxylic acid mimic or bioisosteres are a
tetrazole group of sub-formula (b) and --C(O)NHS(O).sub.2Me.
[0016] In this specification the term "alkyl" includes both
straight and branched chain alkyl groups, unless otherwise stated,
and references to individual alkyl groups such as "propyl" are
specific for the straight chain version only. An analogous
convention applies to other generic terms. Unless otherwise stated
the term "alkyl" advantageously refers to chains with 1-10 carbon
atoms, suitably from 1-6 carbon atoms, preferably 1-4 carbon
atoms.
[0017] In this specification the term "alkoxy" means an alkyl group
as defined hereinbefore linked to an oxygen atom.
[0018] Particular values include for linear (1-3C)alkyl, methyl,
ethyl and propyl; for (1-4C)alkyl, methyl, ethyl, propyl and butyl;
for (2-3C)alkenyl, ethenyl; for (2-3C)alkynyl, ethynyl; for
(1-2C)alkoxy, methoxy and ethoxy; for (1-4C)alkoxy, methoxy, ethoxy
and propoxy; for --CONRbRc, --CONH.sub.2 and --CONHMe.
[0019] Particular values include for any carbon atom in a linear
(1-3C)alkyl, (1-2C)alkoxy, (1-4C)alkyl or (1-4C)alkoxy group that
may be optionally substituted by up to 3 fluoro atoms, a group such
as, for example, trifluoromethyl, difluoromethyl, difluoromethoxy
or trifluoromethoxy.
[0020] For the avoidance of doubt it is to be understood that where
in this specification a group is qualified by `hereinbefore
defined` or `defined hereinbefore` the said group encompasses the
first occurring and broadest definition as well as each and all of
the particular definitions for that group.
[0021] If not stated elsewhere, suitable optional substituents for
a particular group are those as stated for similar groups
herein.
[0022] A compound of formula (I) may form stable acid or basic
salts, and in such cases administration of a compound as a salt may
be appropriate, and pharmaceutically acceptable salts may be made
by conventional methods such as those described following.
[0023] Suitable pharmaceutically-acceptable salts include acid
addition salts such as methanesulfonate, tosylate,
.alpha.-glycerophosphate, fumarate, hydrochloride, citrate,
maleate, tartrate and (less preferably) hydrobromide. Also suitable
are salts formed with phosphoric and sulfuric acid. In another
aspect suitable salts are base salts such as Group (I) (alkali
metal) salt, Group (II) (alkaline earth) metal salt, an organic
amine salt for example triethylamine, morpholine,
N-methylpiperidine, N-ethylpiperidine, procaine, dibenzylamine,
N,N-dibenzylethylamine, tris-(2-hydroxyethyl)amine, N-methyl
d-glucamine and amino acids such as lysine. There may be more than
one cation or anion depending on the number of charged functions
and the valency of the cations or anions.
[0024] Other suitable pharmaceutically-acceptable salts are
mentioned in, for example, Berge et al. (J. Pharm. Sci., 1977, 66,
1-19) and/or Handbook of Pharmaceutical Salts: Properties,
Selection and Use by Stahl and Wermuth (Wiley-VCH, 2002), each of
which is incorporated herein by reference.
[0025] A feature of the invention relates to a compound of the
invention, such as any one of the Examples, in the free acid or
free base form or as a pharmaceutically acceptable salt thereof.
Such forms may be prepared by standard techniques.
[0026] However, to facilitate isolation of the salt during
preparation, salts which are less soluble in the chosen solvent may
be preferred whether pharmaceutically-acceptable or not.
[0027] Within the present invention it is to be understood that a
compound of the formula (I) or a salt thereof may exhibit the
phenomenon of tautomerism and that the formulae drawings (for
example those for group Q) within this specification can represent
only one of the possible tautomeric forms. It is to be understood
that the invention encompasses any tautomeric form which inhibits
DGAT1 activity and is not to be limited merely to any one
tautomeric form utilised within the formulae drawings.
[0028] Pro-drugs of compounds of formula (I), and salts thereof,
are also within the scope of the invention.
[0029] Various forms of prodrugs are known in the art. For examples
of such prodrug derivatives, see: [0030] a) Design of Prodrugs,
edited by H. Bundgaard, (Elsevier, 1985) and Methods in Enzymology,
Vol. 42, p. 309-396, edited by K. Widder, et al. (Academic Press,
1985); [0031] b) A Textbook of Drug Design and Development, edited
by Krogsgaard-Larsen and H. Bundgaard, Chapter 5 "Design and
Application of Prodrugs", by H. Bundgaard p. 113-191 (1991); [0032]
c) H. Bundgaard, Advanced Drug Delivery Reviews, 8, 1-38 (1992);
[0033] d) H. Bundgaard, et al., Journal of Pharmaceutical Sciences,
77, 285 (1988); and [0034] e) N. Kakeya, et al., Chem Pharm Bull,
32, 692 (1984), each of which is incorporated herein by
reference.
[0035] Examples of such prodrugs are in vivo cleavable esters of a
compound of the invention. An in vivo cleavable ester of a compound
of the invention containing a carboxy group is, for example, a
pharmaceutically-acceptable ester which is cleaved in the human or
animal body to produce the parent acid. Suitable
pharmaceutically-acceptable esters for carboxy include (1-6C)alkyl
esters, for example methyl or ethyl; (1-6C)alkoxymethyl esters, for
example methoxymethyl; (1-6C)alkanoyloxymethyl esters, for example
pivaloyloxymethyl; phthalidyl esters;
(3-8C)cycloalkoxycarbonyloxy(1-6C)alkyl esters, for example
1-cyclohexylcarbonyloxyethyl; 1,3-dioxolan-2-ylmethyl esters, for
example 5-methyl-1,3-dioxolan-2-ylmethyl;
(1-6C)alkoxycarbonyloxyethyl esters, for example
1-methoxycarbonyloxyethyl; aminocarbonylmethyl esters and mono- or
di-N-((1-6C)alkyl) versions thereof, for example
N,N-dimethylaminocarbonylmethyl esters and
N-ethylaminocarbonylmethyl esters; and may be formed at any carboxy
group in the compounds of this invention. An in vivo cleavable
ester of a compound of the invention containing a hydroxy group is,
for example, a pharmaceutically-acceptable ester which is cleaved
in the human or animal body to produce the parent hydroxy group.
Suitable pharmaceutically acceptable esters for hydroxy include
(1-6C)alkanoyl esters, for example acetyl esters; and benzoyl
esters wherein the phenyl group may be substituted with aminomethyl
or N-substituted mono- or di-(1-6C)alkyl aminomethyl, for example
4-aminomethylbenzoyl esters and 4-N,N-dimethylaminomethylbenzoyl
esters.
[0036] Particular prodrugs are an ester of a carboxy group selected
from a (1-6C)alkyl ester, a (1-6C)alkoxymethyl ester, a
(1-6C)alkanoyloxymethyl ester, a phthalidyl ester, a
(3-8C)cycloalkoxycarbonyloxy(1-6C)alkyl ester, a
1,3-dioxolan-2-ylmethyl ester, a (1-6C)alkoxycarbonyloxyethyl
ester, an aminocarbonylmethyl ester and a mono- or
di-N-((1-6C)alkyl) version of an aminocarbonylmethyl ester.
[0037] Particular prodrugs are (1-4C)alkyl esters of the carboxylic
acid in compounds of formula (I).
[0038] It will be appreciated by those skilled in the art that
certain compounds of formula (I) contain asymmetrically substituted
carbon and/or sulfur atoms, and accordingly may exist in, and be
isolated in, optically-active and racemic forms. Some compounds of
formula (I) may exhibit polymorphism. It is to be understood that
the present invention encompasses any racemic, optically-active,
polymorphic or stereoisomeric form, or mixtures thereof, which form
possesses properties useful in the inhibition of DGAT1 activity, it
being well known in the art how to prepare optically-active forms
(for example, by resolution of the racemic form by
recrystallization techniques, by synthesis from optically-active
starting materials, by chiral synthesis, by enzymatic resolution,
by biotransformation, or by chromatographic separation using a
chiral stationary phase) and how to determine efficacy for the
inhibition of DGAT1 activity by the standard tests described
hereinafter.
[0039] It is also to be understood that certain compounds of the
formula (I) and salts thereof can exist in solvated as well as
unsolvated forms such as, for example, hydrated forms. It is to be
understood that the invention encompasses all such solvated forms
which inhibit DGAT1 activity.
[0040] As stated before, a range of compounds are provided that
have good DGAT1 inhibitory activity. They have good physical and/or
pharmacokinetic properties in general. The compounds possess
particular, desirable pharmaceutical and/or physical and/or
pharmacokinetic/dynamic and/or toxicological properties and/or
selective activity for DGAT1.
[0041] In one embodiment there is provided a compound as claimed in
any one of the claims, or a pharmaceutically-acceptable salt, or
pro-drug thereof, wherein the pyrazine is substituted on an
available carbon atom by one or two linear (1-3C)alkyl
substituents, in particular methyl, and in particular dimethyl.
[0042] Particular values of substituents in compounds of formula
(I) are as follows (such values may be used where appropriate with
any of the other values, definitions, claims or embodiments defined
hereinbefore or hereinafter), for example the skilled man will
understand that, for example, the particular values (2) and (3)
below may be incorporated into any of the claims or embodiments
herein to define a scope in which the pyrazine is dimethyl-pyrazine
. . . [0043] (1) X.sub.1 is linear (1-3C)alkyl; [0044] (2) X.sub.1
is methyl or ethyl, particularly methyl; [0045] (3) each X.sub.1 is
methyl [0046] (4) r is 1; [0047] (5) r is 2 [0048] (6) r is 2 and
each X.sub.1 is linear (1-3C)alkyl; [0049] (7) r is 2 and each
X.sub.1 is methyl; [0050] (8) q is 0 or 1; [0051] (9) one q is 0
and one q is 1; [0052] (10) X.sub.2 is bromo, fluoro or chloro;
[0053] (11) X.sub.2 is fluoro or chloro; [0054] (12) X.sub.2 is
fluoro; [0055] (13) Y.sub.1 is fluoro, chloro, methyl or
trifluoromethyl; [0056] (14) Y.sub.1 is fluoro or chloro; [0057]
(15) Y.sub.1 is chloro; [0058] (16) n is 0 or 1; [0059] (17) n is
0; [0060] (18) Y.sub.2 is fluoro, chloro or (1-3C)alkyl; [0061]
(19) Y.sub.2 is fluoro, chloro or methyl; [0062] (20) p is 0 or 1;
[0063] (21) p is 2; [0064] (22) Y.sub.3 is fluoro, chloro,
(1-3C)alkyl or a cyclopropyl or cyclobutyl ring (formed from two
Y.sub.3 groups); [0065] (23) Y.sub.3 is (1-3C)alkyl or a
cyclopropyl or cyclobutyl ring (formed from two Y.sub.3 groups);
[0066] (24) p is 2 and Y.sub.3 forms a (3-5C)cycloalkyl ring;
[0067] (25) Z is carboxy or --CONRbRc or
[0067] ##STR00012## [0068] (26) Z is carboxy or --CONRbRc; [0069]
(27) Z is --CONRbRc; [0070] (28) Z is carboxy; [0071] (29) Rb is
(1-4C)alkyl, optionally substituted by carboxy; [0072] (30) Rc is
hydrogen or (1-4C)alkyl; [0073] (31) Rc is hydrogen or methyl, for
example hydrogen; [0074] (32) any carbon atom in a linear
(1-3C)alkyl, (1-3C)alkyl or (1-2C)alkoxy containing group in
X.sub.2, Y.sub.2 or Y.sub.1 may be optionally substituted by up to
3 fluoro atoms; [0075] (33) Z is --CONRbRc and Rb and Rc are linked
so as to form a morpholine ring or a (4-6C)heterocyclic ring, such
as an azetidine ring; [0076] (34) Z is --CONRbRc and Rb and Rc are
linked so as to form a morpholine ring or a (4-6C)heterocyclic
ring, such as a piperidine ring; [0077] (35) Z is --CONRbRc and the
(1-4C)alkyl group and the morpholine or (4-6C)heterocyclic rings
that may be formed by Rb and Rc are substituted on an available
carbon atom by a carboxy group Q. [0078] (36) Z is --CONRbRc and
the (1-4C)alkyl group and the morpholine or (4-6C)heterocyclic
rings that may be formed by Rb and Rc are substituted on an
available carbon atom by a carboxy group or a group Q.
[0079] Thus, in another embodiment is a compound of formula (I), or
a pharmaceutically-acceptable salt, or pro-drug thereof, wherein
each r is 1 and each X.sub.1 is methyl;
each q is independently 0 or 1 and each X.sub.2 is independently
selected from fluoro and chloro; Y.sub.1 is selected from fluoro,
chloro, and (1-3C)alkyl; n is 0 or 1 and each Y.sub.2 is
independently selected from fluoro, chloro and (1-3C)alkyl; p is 0,
1 or 2 and Y.sub.3 is independently (1-3C)alkyl or when p is 2 each
Y.sub.3 may also link to form a (3-5C)cycloalkyl ring; Z is carboxy
or a group Q selected from --CONHSO.sub.2Me or one of the following
rings,
##STR00013##
or Z is --CONRbRc wherein Rb and Rc are independently selected from
hydrogen, (1-4C)alkyl and (1-4C)alkoxyethyl or Rb and Rc are linked
so as to form a morpholine ring or a (4-6C)heterocyclic ring, and
when Z is --CONRbRc the (1-4C)alkyl group and morpholine or
(4-6C)heterocyclic rings that may be formed may be optionally
substituted on an available carbon atom by carboxy or a group Q;
and wherein any carbon atom in a linear (1-3C)alkyl, (1-3C)alkyl or
(1-2C)alkoxy containing group defined above may be optionally
substituted by up to 3 fluoro atoms.
[0080] In another embodiment is a compound of formula (I), or a
pharmaceutically-acceptable salt, or pro-drug thereof, wherein
each r is 1 and each X.sub.1 is (1-3C)alkyl, for example methyl;
each q is independently 0, 1 or 2 and each X.sub.2 is independently
selected from fluoro and chloro; Y.sub.1 is selected from fluoro,
chloro, and (1-3C)alkyl optionally substituted by upto three
fluorine atoms; n is 0 or 1 and each Y.sub.2 is independently
selected from fluoro, chloro and (1-3C)alkyl; p is 0, 1 or 2 and
Y.sub.3 is independently (1-3C)alkyl or when p is 2 each Y.sub.3
may also link to form a (3-5C)cycloalkyl ring; Z is carboxy or a
group Q selected from one of the following rings,
##STR00014##
for example Z is carboxy, or a group
##STR00015##
or Z is --CONRbRc wherein Rb and Rc are independently selected from
hydrogen and (1-4C)alkyl or Rb and Rc are linked so as to form a
(4-6C)heterocyclic ring, for example piperidine, and when Z is
--CONRbRc the (1-4C)alkyl group and (4-6C)heterocyclic ring that
may be formed may be optionally substituted on an available carbon
atom by carboxy.
[0081] In another embodiment there is provided a compound of
formula (I) as defined in any of the embodiments herein wherein a
pro-drug for Z as carboxy is a (1-6C)alkyl ester.
[0082] A further feature is any of the scopes defined herein with
the proviso that specific Examples, such as Example 1, 2, 3, 4 etc.
are individually disclaimed.
[0083] Further particular compounds of the invention are each of
the Examples, each of which provides a further independent aspect
of the invention. In further aspects, the present invention also
comprises any particular compounds of the Examples or a
pharmaceutically-acceptable salt thereof (such as, for example, a
sodium, magnesium, tert-butylammonium,
tris(hydroxymethyl)methylammonium, triethanolammonium,
diethanolammonium, ethanolammonium, methylethanolammonium,
diethylammonium or nicotinamide salt).
[0084] In a further aspect, the present invention also comprises
any particular isomers of compounds of the Examples, or a
pharmaceutically-acceptable salt of any of these.
[0085] A compound of formula (I) and its salts may be prepared by
any process known to be applicable to the preparation of chemically
related compounds. Such processes, when used to prepare a compound
of the formula (I), or a pharmaceutically-acceptable salt thereof,
are provided as a further feature of the invention.
[0086] In a further aspect the present invention also provides that
the compounds of the formula (I) and salts thereof, can be prepared
by the following processes, the processes of the Examples and
analogous processes (wherein all variables are as hereinbefore
defined for a compound of formula (I) unless otherwise stated) and
thereafter if necessary any protecting groups can be removed and/or
an appropriate salt formed. Any defined carboxylic acid groups may
be replaced as appropriate by a mimic or bioisostere thereof, in
particular groups defined as Q herein.
[0087] Variables shown in the schemes are defined or can be
interpreted in the context of the variants described herein for the
compounds of the invention. Analogous chemistry to that shown in
the schemes and Examples may be used to prepare other ring variants
and linking group options within the scope of the invention.
[0088] Also included as an aspect of the invention are the
compounds obtainable by any of the processes or Examples described
herein.
Process A
[0089] By modifying a substituent in, or introducing a substituent
into, another compound of formula (I). Suitable methods for
converting substituents into other substituents are known in the
art; for example, an acid group may be converted into an amide
group.
[0090] Compounds of formula (I) where, for example, Z is an
acylsulfonamide group or Z is a tetrazole or oxadiazolone may be
prepared from the corresponding carboxylic acid. The tetrazole may
be introduced early in the synthetic route via an amide (which, for
primary amides, may be converted to the nitrile by standard
methods) which is then in turn converted into a tetrazole by
reaction with azide. The tetrazole may be carried through the rest
of the synthesis in protected form, e.g. N-benzylated or
N-(2-cyanoethyl)ated. Similarly, the nitriles described above may
be converted early in the synthetic sequence to an oxadiazolone by
standard methods.
Process B
[0091] As described in the following processes (wherein the
variables are appropriately as defined in any of the claims,
embodiments or Examples herein), Suzuki coupling of an appropriate
triflate, iodo-, bromo- or chloro-substituted aromatic compound can
be performed with a suitably substituted intermediate
boron-containing compound using standard methods with a suitable
palladium catalyst, such as
1,1'-bis(diphenylphosphino)-ferrocenedichloro-palladium(II).
[0092] Process B1
[0093] Suzuki coupling of an appropriate triflate, iodo-, bromo- or
chloro-substituted pyrazine derivative (IV) with a suitably
substituted intermediate boron-containing compound of formula
(II).
##STR00016##
[0094] X in formula (IV) represents a leaving group such as
triflate, iodo-, bromo- or chloro and E in formula (II) represents
a boronic acid (--B(OH).sub.2) or a derivative thereof such as a
boronate ester (--B(OR).sub.2 wherein R here is (1-4C)alkyl) or a
cyclic boronate ester, such as pinacolato borane
(4,4,5,5-tetramethyl-1,3,2-dioxaborolane).
[0095] Alternatively a Suzuki coupling of an appropriate triflate,
iodo-, bromo- or chloro-pyrazine ester (III), particularly bromo-
or chloro-pyrazine ethyl ester (III), can be used followed by
removal of the protecting group by basic hydrolysis (for example of
a methyl or ethyl ester). The pyrazine acid is then converted to
the corresponding primary carboxamide by reaction with ammonia in
the presence of a coupling agent, for example PyBOP.
##STR00017##
[0096] X in formula (III) represents a leaving group such as
triflate, iodo-, bromo- or chloro.
[0097] An illustration of Process B1 is provided in the scheme
below (for the dimethyl pyrazine variant) in which (Tf).sub.2O or
PhNTf.sub.2 may be used.
##STR00018##
[0098] In Scheme B1, the variable substituents are those which are
compatible with the reaction conditions. A protecting group, if
used, can be removed, for example, by acid catalysed hydrolysis of
a tert-butyl ester to give a compound of formula (I) where
Z.dbd.CO.sub.2H.
Preparation of Formula (III) Compounds
[0099] The following schemes illustrate how certain pyrazine ring
variants may be prepared. Variables shown in the schemes are
defined or can be interpreted in the context of the variants
described herein for the compounds of the invention. Analogous
chemistry to that shown in the schemes and Examples may be used to
prepare other compounds within the scope of the invention.
##STR00019##
[0100] R in Scheme B1-A represents (1-4C)alkyl, for example, methyl
or ethyl.
##STR00020##
Preparation of Formula (III) and (IV) Compounds
##STR00021##
[0102] Analogues of pyrazine can be prepared using the procedure
described by C. Christensen, C. W. Tornoe and M. Meldal, QSAR &
Combinatorial Science, 2004, 23, (2-3), 109-116, for example,
3-methylpyrazine . . .
##STR00022##
Preparation of Formula (II) Compounds
[0103] The following schemes illustrate how certain variants may be
prepared. Variables shown in the schemes are defined or can be
interpreted in the context of the variants described herein for the
compounds of the invention. Analogous chemistry to that shown in
the schemes and Examples may be used to prepare other compounds
within the scope of the invention.
[0104] For compounds of formula (II) many appropriate intermediates
are in the literature, or can be made by analogy, and introduction
of various substitution patterns may be achieved through biphenyl
Suzuki coupling (see Scheme B1-E):
##STR00023##
[0105] In Scheme B1-E, X represents triflate, iodo-, bromo- or
chloro and E represents a boronic acid (--B(OH).sub.2), a boronate
ester (--B(OR).sub.2 wherein R here is (1-4C)alkyl) or a cyclic
boronic ester, such as pinacolato borane.
[0106] The bromobiphenyl is then converted into the corresponding
boron-containing derivative by standard methods.
[0107] For introduction of .alpha.-alkyl, dialkyl and cycloalkyl
groups at the "Y.sub.3 substitution position" standard alkylation
methodology may be used on any suitable boronate ester compound,
for example by deprotonation .alpha.-to the ester group using a
lithium base such as LDA followed by quenching with an appropriate
alkyl halide or alkyldihalide. Such chemistry is applicable in
Process B1 and also Process B3 (see later).
[0108] Process B2
[0109] In an alternative sequence of Suzuki couplings a boronic
ester of formula (V) is generated as an intermediate (wherein E
represents a boronic acid (--B(OH).sub.2), a boronate ester
(--B(OR).sub.2 wherein R here is (1-4C)alkyl) or a cyclic boronic
ester, such as pinacolato borane), as illustrated by the scheme
below (for the dimethylpyrazine variant). This intermediate is then
used in a further Suzuki coupling to generate biphenyl compounds of
formula (I).
Preparation of Formula (V) Compound Types (Ring A and Ring B)
##STR00024##
[0111] In Scheme B2-A, suitable aromatic substituents are those
compatible with the reaction conditions. The phenol is converted
into the corresponding triflate with PhN(Tf).sub.2 and a suitable
base, such as potassium carbonate. The phenyltriflate is converted
to the corresponding boronate ester followed by subsequent Suzuki
reaction under standard methods with a suitable palladium catalyst,
such as 1,1'-bis(diphenylphosphino)-ferrocenedichloropalladium(II).
Alternatively, the boronate ester can be converted to the
corresponding boronic acid.
##STR00025##
[0112] The compound of formula (V-B) can be prepared from the
corresponding phenol compound by standard chemistry or from the
corresponding methoxy compound after demethylation using
BBr.sub.3.
[0113] Process B3
[0114] In an alternative sequence of Suzuki couplings a
boron-containing compound of formula (VI) (wherein E represents a
boronic acid (--B(OH).sub.2), a boronate ester (--B(OR).sub.2
wherein R here is (1-4C)alkyl) or a cyclic boronic ester, such as
pinacolato borane) is generated as an intermediate and reacted with
the triflate of formula (V-A) in Scheme B2-A to generate biphenyl
compounds of the formula (I).
##STR00026##
##STR00027##
[0115] Chiral compounds (for example at the "Y3" position) can be
prepared as follows . . . [0116] (i) by chromatographic separation
from a final mixture of compounds (for example, see the Examples);
suitable hplc chiral stationary phases include Chiralpak OJ and AD
columns; [0117] (ii) by directed methylation utilising a chiral
auxilliary by the method described by J. S Yadav et al Tet. Lett.
2007, 48, 2841-2843 and illustrated in the scheme below, followed
by Suzuki coupling and hydrolytic cleavage of the auxilliary to
afford a single enantiomer of the relavent Example compound;
[0117] ##STR00028## [0118] (iii) by final chiral reduction of an
alpha-methylene acid by catalytic hydrogenation, for example as
described by R Noyori et al. J. Org. Chem., 1987, 52, 3174-3176 and
illustrated in the scheme below:
##STR00029##
[0119] Such alpha-methylene acids may be prepared by reaction of
the corresponding alpha-unsubstituted esters with formaldehyde or
equivalent under standard conditions followed by basic hydrolysis
of the ester.
[0120] If not commercially available, the necessary starting
materials for the procedures such as those described above may be
made by procedures which are selected from standard organic
chemical techniques, techniques which are analogous to the
synthesis of known, structurally similar compounds, techniques
which are described or illustrated in the references given above,
or techniques which are analogous to the above described procedure
or the procedures described in the examples. The reader is further
referred to Advanced Organic Chemistry, 5.sup.th Edition, by Jerry
March and Michael Smith, published by John Wiley & Sons 2001,
for general guidance on reaction conditions and reagents.
[0121] It will be appreciated that some intermediates to compounds
of the formula (I) are also novel and these are provided as
separate independent aspects of the invention. In particular,
certain compounds of formula (IV) may form a further independent
aspect of the invention. Furthermore, ester derivatives of
compounds of formula (I) form a further aspect of the
invention.
[0122] It will also be appreciated that in some of the reactions
mentioned herein it may be necessary/desirable to protect any
sensitive groups in compounds. The instances where protection is
necessary or desirable are known to those skilled in the art, as
are suitable methods for such protection. Conventional protecting
groups may be used in accordance with standard practice (for
illustration see T. W. Greene, Protective Groups in Organic
Synthesis, John Wiley and Sons, 1991).
[0123] Protecting groups may be removed by any convenient method as
described in the literature or known to the skilled chemist as
appropriate for the removal of the protecting group in question,
such methods being chosen so as to effect removal of the protecting
group with minimum disturbance of groups elsewhere in the
molecule.
[0124] Thus, if reactants include, for example, groups such as
amino, carboxy or hydroxy it may be desirable to protect the group
in some of the reactions mentioned herein.
[0125] Examples of a suitable protecting group for a hydroxy group
is, for example, an acyl group, for example an alkanoyl group such
as acetyl, an aroyl group, for example benzoyl, a silyl group such
as trimethylsilyl or an arylmethyl group, for example benzyl. The
deprotection conditions for the above protecting groups will
necessarily vary with the choice of protecting group. Thus, for
example, an acyl group such as an alkanoyl or an aroyl group may be
removed, for example, by hydrolysis with a suitable base such as an
alkali metal hydroxide, for example lithium or sodium hydroxide.
Alternatively a silyl group such as trimethylsilyl or SEM may be
removed, for example, by fluoride or by aqueous acid; or an
arylmethyl group such as a benzyl group may be removed, for
example, by hydrogenation in the presence of a catalyst such as
palladium-on-carbon.
[0126] A suitable protecting group for an amino group is, for
example, an acyl group, for example an alkanoyl group such as
acetyl, an alkoxycarbonyl group, for example a methoxycarbonyl,
ethoxycarbonyl or tert-butoxycarbonyl group, an arylmethoxycarbonyl
group, for example benzyloxycarbonyl, or an aroyl group, for
example benzoyl. The deprotection conditions for the above
protecting groups necessarily vary with the choice of protecting
group. Thus, for example, an acyl group such as an alkanoyl or
alkoxycarbonyl group or an aroyl group may be removed for example,
by hydrolysis with a suitable base such as an alkali metal
hydroxide, for example lithium or sodium hydroxide. Alternatively
an acyl group such as a t-butoxycarbonyl group may be removed, for
example, by treatment with a suitable acid as hydrochloric,
sulfuric or phosphoric acid or trifluoroacetic acid and an
arylmethoxycarbonyl group such as a benzyloxycarbonyl group may be
removed, for example, by hydrogenation over a catalyst such as
palladium-on-carbon, or by treatment with a Lewis acid for example
boron tris(trifluoroacetate). A suitable alternative protecting
group for a primary amino group is, for example, a phthaloyl group
which may be removed by treatment with an alkylamine, for example
dimethylaminopropylamine or 2-hydroxyethylamine, or with
hydrazine.
[0127] A suitable protecting group for a carboxy group is, for
example, an esterifying group, for example a methyl or an ethyl
group which may be removed, for example, by hydrolysis with a base
such as sodium hydroxide, or for example a t-butyl group which may
be removed, for example, by treatment with an acid, for example an
organic acid such as trifluoroacetic acid, or for example a benzyl
group which may be removed, for example, by hydrogenation over a
catalyst such as palladium-on-carbon.
[0128] Resins may also be used as a protecting group.
[0129] The protecting groups may be removed at any convenient stage
in the synthesis using conventional techniques well known in the
chemical art, or they may be removed during a later reaction step
or work-up.
[0130] The skilled organic chemist will be able to use and adapt
the information contained and referenced within the above
references, and accompanying Examples therein and also the examples
herein, to obtain necessary starting materials, and products.
[0131] The removal of any protecting groups and the formation of a
pharmaceutically-acceptable salt are within the skill of an
ordinary organic chemist using standard techniques. Furthermore,
details on the these steps has been provided hereinbefore.
[0132] When an optically active form of a compound of the invention
is required, it may be obtained by carrying out one of the above
procedures using an optically active starting material (formed, for
example, by asymmetric induction of a suitable reaction step), or
by resolution of a racemic form of the compound or intermediate
using a standard procedure, or by chromatographic separation of
diastereoisomers (when produced). Enzymatic techniques may also be
useful for the preparation of optically active compounds and/or
intermediates.
[0133] Similarly, when a pure regioisomer of a compound of the
invention is required, it may be obtained by carrying out one of
the above procedures using a pure regioisomer as a starting
material, or by resolution of a mixture of the regioisomers or
intermediates using a standard procedure.
[0134] According to a further aspect of the invention there is
provided a pharmaceutical composition which comprises a compound of
formula (I) as defined hereinbefore or a
pharmaceutically-acceptable salt thereof, in association with a
pharmaceutically-acceptable excipient or carrier.
[0135] The compositions of the invention may be in a form suitable
for oral use (for example as tablets, lozenges, hard or soft
capsules, aqueous or oily suspensions, emulsions, dispersible
powders or granules, syrups or elixirs), for topical use (for
example as creams, ointments, gels, or aqueous or oily solutions or
suspensions), for administration by inhalation (for example as a
finely divided powder or a liquid aerosol), for administration by
insufflation (for example as a finely divided powder) or for
parenteral administration (for example as a sterile aqueous or oily
solution for intravenous, subcutaneous, intramuscular or
intramuscular dosing or as a suppository for rectal dosing).
[0136] The compositions of the invention may be obtained by
conventional procedures using conventional pharmaceutical
excipients, well known in the art. Thus, compositions intended for
oral use may contain, for example, one or more colouring,
sweetening, flavouring and/or preservative agents.
[0137] Suitable pharmaceutically acceptable excipients for a tablet
formulation include, for example, inert diluents such as lactose,
sodium carbonate, calcium phosphate or calcium carbonate,
granulating and disintegrating agents such as corn starch or
algenic acid; binding agents such as starch; lubricating agents
such as magnesium stearate, stearic acid or talc; preservative
agents such as ethyl or propyl p-hydroxybenzoate, and
anti-oxidants, such as ascorbic acid. Tablet formulations may be
uncoated or coated either to modify their disintegration and the
subsequent absorption of the active ingredient within the
gastrointestinal tract, or to improve their stability and/or
appearance, in either case, using conventional coating agents and
procedures well known in the art.
[0138] Compositions for oral use may be in the form of hard gelatin
capsules in which the active ingredient is mixed with an inert
solid diluent, for example, calcium carbonate, calcium phosphate or
kaolin, or as soft gelatin capsules in which the active ingredient
is mixed with water or an oil such as peanut oil, liquid paraffin,
or olive oil.
[0139] Aqueous suspensions generally contain the active ingredient
in finely powdered form together with one or more suspending
agents, such as sodium carboxymethylcellulose, methylcellulose,
hydroxypropylmethylcellulose, sodium alginate,
polyvinyl-pyrrolidone, gum tragacanth and gum acacia; dispersing or
wetting agents such as lecithin or condensation products of an
alkylene oxide with fatty acids (for example polyoxethylene
stearate), or condensation products of ethylene oxide with long
chain aliphatic alcohols, for example heptadecaethyleneoxycetanol,
or condensation products of ethylene oxide with partial esters
derived from fatty acids and a hexitol such as polyoxyethylene
sorbitol monooleate, or condensation products of ethylene oxide
with long chain aliphatic alcohols, for example
heptadecaethyleneoxycetanol, or condensation products of ethylene
oxide with partial esters derived from fatty acids and a hexitol
such as polyoxyethylene sorbitol monooleate, or condensation
products of ethylene oxide with partial esters derived from fatty
acids and hexitol anhydrides, for example polyethylene sorbitan
monooleate. The aqueous suspensions may also contain one or more
preservatives (such as ethyl or propyl p-hydroxybenzoate,
anti-oxidants (such as ascorbic acid), colouring agents, flavouring
agents, and/or sweetening agents (such as sucrose, saccharine or
aspartame).
[0140] Oily suspensions may be formulated by suspending the active
ingredient in a vegetable oil (such as arachis oil, olive oil,
sesame oil or coconut oil) or in a mineral oil (such as liquid
paraffin). The oily suspensions may also contain a thickening agent
such as beeswax, hard paraffin or cetyl alcohol. Sweetening agents
such as those set out above, and flavouring agents may be added to
provide a palatable oral preparation. These compositions may be
preserved by the addition of an anti-oxidant such as ascorbic
acid.
[0141] Dispersible powders and granules suitable for preparation of
an aqueous suspension by the addition of water generally contain
the active ingredient together with a dispersing or wetting agent,
suspending agent and one or more preservatives. Suitable dispersing
or wetting agents and suspending agents are exemplified by those
already mentioned above. Additional excipients such as sweetening,
flavouring and colouring agents, may also be present.
[0142] The pharmaceutical compositions of the invention may also be
in the form of oil-in-water emulsions. The oily phase may be a
vegetable oil, such as olive oil or arachis oil, or a mineral oil,
such as for example liquid paraffin or a mixture of any of these.
Suitable emulsifying agents may be, for example,
naturally-occurring gums such as gum acacia or gum tragacanth,
naturally-occurring phosphatides such as soya bean, lecithin, an
esters or partial esters derived from fatty acids and hexitol
anhydrides (for example sorbitan monooleate) and condensation
products of the said partial esters with ethylene oxide such as
polyoxyethylene sorbitan monooleate. The emulsions may also contain
sweetening, flavouring and preservative agents.
[0143] Syrups and elixirs may be formulated with sweetening agents
such as glycerol, propylene glycol, sorbitol, aspartame or sucrose,
and may also contain a demulcent, preservative, flavouring and/or
colouring agent.
[0144] The pharmaceutical compositions may also be in the form of a
sterile injectable aqueous or oily suspension, which may be
formulated according to known procedures using one or more of the
appropriate dispersing or wetting agents and suspending agents,
which have been mentioned above. A sterile injectable preparation
may also be a sterile injectable solution or suspension in a
non-toxic parenterally-acceptable diluent or solvent, for example a
solution in 1,3-butanediol.
[0145] Compositions for administration by inhalation may be in the
form of a conventional pressurised aerosol arranged to dispense the
active ingredient either as an aerosol containing finely divided
solid or liquid droplets. Conventional aerosol propellants such as
volatile fluorinated hydrocarbons or hydrocarbons may be used and
the aerosol device is conveniently arranged to dispense a metered
quantity of active ingredient.
[0146] For further information on formulation the reader is
referred to Chapter 25.2 in Volume 5 of Comprehensive Medicinal
Chemistry (Corwin Hansch; Chairman of Editorial Board), Pergamon
Press 1990.
[0147] The amount of active ingredient that is combined with one or
more excipients to produce a single dosage form will necessarily
vary depending upon the host treated and the particular route of
administration. For example, a formulation intended for oral
administration to humans will generally contain, for example, from
0.5 mg to 2 g of active agent compounded with an appropriate and
convenient amount of excipients which may vary from about 5 to
about 98 percent by weight of the total composition. Dosage unit
forms will generally contain about 1 mg to about 500 mg of an
active ingredient. For further information on Routes of
Administration and Dosage Regimes the reader is referred to Chapter
25.3 in Volume 5 of Comprehensive Medicinal Chemistry (Corwin
Hansch; Chairman of Editorial Board), Pergamon Press 1990.
[0148] According to a further aspect of the present invention there
is provided a compound of formula (I), or a pharmaceutically
acceptable salt, or a pro-drug thereof as defined hereinbefore for
use in a method of treatment of the human or animal body by
therapy.
[0149] We have found that compounds of the present invention
inhibit DGAT1 activity and are therefore of interest for their
blood glucose-lowering effects.
[0150] A further feature of the present invention is a compound of
formula (I), or a pharmaceutically-acceptable salt, or a pro-drug
thereof for use as a medicament.
[0151] Conveniently this is a compound of formula (I), or a
pharmaceutically-acceptable salt, or a pro-drug thereof, for (use
as a medicament for) producing an inhibition of DGAT1 activity in a
warm-blooded animal such as a human being.
[0152] Particularly this is a compound of formula (I), or a
pharmaceutically-acceptable salt, or a pro-drug thereof, for (use
as a medicament for) treating diabetes mellitus and/or obesity in a
warm-blooded animal such as a human being.
[0153] Thus according to a further aspect of the invention there is
provided the use of a compound of formula (I), or a
pharmaceutically-acceptable salt, or a pro-drug thereof in the
manufacture of a medicament for use in the production of an
inhibition of DGAT1 activity in a warm-blooded animal such as a
human being.
[0154] Thus according to a further aspect of the invention there is
provided the use of a compound of formula (I), or a
pharmaceutically-acceptable salt, or a pro-drug thereof in the
manufacture of a medicament for use in the treatment of diabetes
mellitus and/or obesity in a warm-blooded animal such as a human
being.
[0155] According to a further aspect of the invention there is
provided a pharmaceutical composition which comprises a compound of
formula (I) as defined hereinbefore, or a
pharmaceutically-acceptable salt, or a pro-drug thereof, in
association with a pharmaceutically-acceptable excipient or carrier
for use in producing an inhibition of DGAT1 activity in an
warm-blooded animal, such as a human being.
[0156] According to a further aspect of the invention there is
provided a pharmaceutical composition which comprises a compound of
formula (I) as defined hereinbefore, or a
pharmaceutically-acceptable salt, or a pro-drug thereof, in
association with a pharmaceutically-acceptable excipient or carrier
for use in the treatment of diabetes mellitus and/or obesity in an
warm-blooded animal, such as a human being.
[0157] According to a further feature of the invention there is
provided a method for producing an inhibition of DGAT1 activity in
a warm-blooded animal, such as a human being, in need of such
treatment which comprises administering to said animal an effective
amount of a compound of formula (I), or a
pharmaceutically-acceptable salt, or a pro-drug thereof as defined
hereinbefore.
[0158] According to a further feature of the invention there is
provided a method of treating diabetes mellitus and/or obesity in a
warm-blooded animal, such as a human being, in need of such
treatment which comprises administering to said animal an effective
amount of a compound of formula (I), or a
pharmaceutically-acceptable salt, or a pro-drug thereof as defined
hereinbefore.
[0159] As stated above the size of the dose required for the
therapeutic or prophylactic treatment of a particular disease state
will necessarily be varied depending on the host treated, the route
of administration and the severity of the illness being treated.
Preferably a daily dose in the range of 0.1-50 mg/kg is employed.
In another embodiment a daily dose is in the range of 0.01-50
mg/kg, particularly 0.01-10 mg/kg, 0.01-1 mg/kg or 0.01-0.1 mg/kg.
However the daily dose will necessarily be varied depending upon
the host treated, the particular route of administration, and the
severity of the illness being treated. Accordingly the optimum
dosage may be determined by the practitioner who is treating any
particular patient.
[0160] As stated above compounds defined in the present invention
are of interest for their ability to inhibit the activity of DGAT1.
A compound of the invention may therefore be useful for the
prevention, delay or treatment of a range of disease states
including diabetes mellitus, more specifically type 2 diabetes
mellitus (T2DM) and complications arising there from (for example
retinopathy, neuropathy and nephropathy), impaired glucose
tolerance (IGT), conditions of impaired fasting glucose, metabolic
acidosis, ketosis, dysmetabolic syndrome, arthritis, osteoporosis,
obesity and obesity related disorders, (which include peripheral
vascular disease, (including intermittent claudication), cardiac
failure and certain cardiac myopathies, myocardial ischaemia,
cerebral ischaemia and reperfusion, hyperlipidaemias,
atherosclerosis, infertility and polycystic ovary syndrome); the
compounds of the invention may also be useful for muscle weakness,
diseases of the skin such as acne, various immunomodulatory
diseases (such as psoriasis), HIV infection, inflammatory bowel
syndrome and inflammatory bowel disease such as Crohn's disease and
ulcerative colitis.
[0161] In particular, the compounds of the present invention are of
interest for the prevention, delay or treatment of diabetes
mellitus and/or obesity and/or obesity related disorders. In one
aspect, the compounds of the invention are used for prevention,
delay or treatment of diabetes mellitus. In another aspect, the
compounds of the invention are used for prevention, delay or
treatment of obesity. In a further aspect, the compounds of the
invention are used for prevention, delay or treatment of obesity
related disorders.
[0162] The inhibition of DGAT1 activity described herein may be
applied as a sole therapy or in combination with one or more other
substances and/or treatments for the indication being treated. Such
conjoint treatment may be achieved by way of the simultaneous,
sequential or separate administration of the individual components
of the treatment. Simultaneous treatment may be in a single tablet
or in separate tablets. For example such conjoint treatment may be
beneficial in the treatment of metabolic syndrome [defined as
abdominal obesity (as measured by waist circumference against
ethnic and gender specific cut-points) plus any two of the
following: hypertriglyceridemia (>150 mg/dl; 1.7 mmol/1); low
HDLc (<40 mg/dl or <1.03 mmol/1 for men and <50 mg/dl or
1.29 mmol/l for women) or on treatment for low HDL (high density
lipoprotein); hypertension (SBP .gtoreq.130 mmHg DBP .gtoreq.85
mmHg) or on treatment for hypertension; and hyperglycemia (fasting
plasma glucose .gtoreq.100 mg/dl or 5.6 mmol/l or impaired glucose
tolerance or pre-existing diabetes mellitus)--International
Diabetes Federation & input from IAS/NCEP].
[0163] Such conjoint treatments may include the following main
categories:
1) Anti-obesity therapies such as those that cause weight loss by
effects on food intake, nutrient absorption or energy expenditure,
such as orlistat, sibutramine and the like. 2) Insulin
secretagogues including sulphonylureas (for example glibenclamide,
glipizide), prandial glucose regulators (for example repaglinide,
nateglinide); 3) Agents that improve incretin action (for example
dipeptidyl peptidase IV inhibitors, and GLP-1 agonists); 4) Insulin
sensitising agents including PPARgamma agonists (for example
pioglitazone and rosiglitazone), and agents with combined PPARalpha
and gamma activity; 5) Agents that modulate hepatic glucose balance
(for example metformin, fructose 1,6 bisphosphatase inhibitors,
glycogen phopsphorylase inhibitors, glycogen synthase kinase
inhibitors, glucokinase activators); 6) Agents designed to reduce
the absorption of glucose from the intestine (for example
acarbose); 7) Agents that prevent the reabsorption of glucose by
the kidney (SGLT inhibitors); 8) Agents designed to treat the
complications of prolonged hyperglycaemia (for example aldose
reductase inhibitors); 9) Anti-dyslipidaemia agents such as,
HMG-CoA reductase inhibitors (eg statins); PPAR .alpha.-agonists
(fibrates, eg gemfibrozil); bile acid sequestrants
(cholestyramine); cholesterol absorption inhibitors (plant stanols,
synthetic inhibitors); bile acid absorption inhibitors (IBATi) and
nicotinic acid and analogues (niacin and slow release
formulations); 10) Antihypertensive agents such as .beta.-blockers
(eg atenolol, inderal); ACE inhibitors (eg lisinopril); Calcium
antagonists (eg. nifedipine); Angiotensin receptor antagonists (eg
candesartan), .alpha.-antagonists and diuretic agents (eg.
furosemide, benzthiazide); 11) Haemostasis modulators such as,
antithrombotics, activators of fibrinolysis and antiplatelet
agents; thrombin antagonists; factor Xa inhibitors; factor VIIa
inhibitors); antiplatelet agents (eg. aspirin, clopidogrel);
anticoagulants (heparin and Low molecular weight analogues,
hirudin) and warfarin; 12) Agents which antagonise the actions of
glucagon; and 13) Anti-inflammatory agents, such as non-steroidal
anti-inflammatory drugs (eg. aspirin) and steroidal
anti-inflammatory agents (eg. cortisone).
[0164] In addition to their use in therapeutic medicine, compounds
of formula (I) and their pharmaceutically-acceptable salts are also
useful as pharmacological tools in the development and
standardisation of in vitro and in vivo test systems for the
evaluation of the effects of inhibitors of DGAT1 activity in
laboratory animals such as cats, dogs, rabbits, monkeys, rats and
mice, as part of the search for new therapeutic agents.
[0165] In the above other pharmaceutical composition, process,
method, use and medicament manufacture features, the alternative,
particular and preferred embodiments of the compounds of the
invention described herein also apply. The alternative, particular
and preferred embodiments of the invention described herein also
apply to a compound of formula (I), or a
pharmaceutically-acceptable salt, or a pro-drug thereof.
[0166] As indicated above, all of the compounds, and their
corresponding pharmaceutically-acceptable salts, are useful in
inhibiting DGAT1. The ability of the compounds of formula (I), and
their corresponding pharmaceutically-acceptable (acid addition)
salts, to inhibit DGAT1 may be demonstrated employing the following
enzyme assay:
Human Enzyme Assay
[0167] See, for example, International Application WO
2005/044250.
[0168] The in vitro assay to identify DGAT1 inhibitors uses human
DGAT1 expressed in insect cell membranes as the enzyme source
(Proc. Natl. Acad. Sci. 1998, 95, 13018-13023). Briefly, sf9 cells
were infected with recombinant baculovirus containing human DGAT1
coding sequences and harvested after 48 h. Cells were lysed by
sonication and membranes isolated by centrifuging at 28000 rpm for
1 h at 4.degree. C. on a 41% sucrose gradient. The membrane
fraction at the interphase was collected, washed, and stored in
liquid nitrogen.
[0169] DGAT1 activity was assayed by a modification of the method
described by Coleman (Methods in Enzymology 1992, 209, 98-102).
Compound at 0.0000256 .mu.M (or 0.003 .mu.M)-33 .mu.M (final conc.)
(typically 10 .mu.M) was incubated with 4 .mu.g/ml (final cone)
membrane protein, 5 mM MgCl.sub.2, and 100 .mu.M 1,2
dioleoyl-sn-glycerol (dissolved in acetone with a final assay conc.
of acetone of 10%) in a total assay volume of 200 .mu.l in a 96
well plate. The reaction was started by adding .sup.14C oleoyl
coenzyme A (30 .mu.M final concentration) and incubated at room
temperature for 30 minutes. The reaction was stopped by adding 200
.mu.l 2-propanol:heptane 7:1. Radioactive triolein product was
separated into the organic phase by adding 300 .mu.l heptane and
100 .mu.l 0.1 M carbonate buffer pH 9.5. DGAT1 activity was
quantified by counting aliquots of the upper heptane layer by
liquid scintillography.
[0170] Using this assay the compounds generally show activity with
an IC.sub.50 around or below 10 .mu.M, preferably below 10 .mu.M
(i.e. IC.sub.50<10 .mu.M), preferably <1 .mu.M, more
preferably <0.1 .mu.M, particularly, <0.05 .mu.M, and more
particularly <0.01 .mu.M. Stated figures are usually a mean of a
number of measurements (usually 2 measurements) according to
standard practice.
[0171] Examples 1 to 10 showed, respectively, an IC.sub.50=0.0061
.mu.M; 0.0077 .mu.M; 0.017 .mu.M; 0.012 .mu.M; 0.014 .mu.M; 0.018
.mu.M; 0.027 .mu.M; 0.012 .mu.M; 0.018 .mu.M; 0.011 .mu.M.
[0172] Examples 11 to 20 showed, respectively, IC.sub.50=0.017
.mu.M; 0.02 .mu.M; 0.021 .mu.M; 0.0036 .mu.M; 0.011 .mu.M; 0.013
.mu.M; 0.013 .mu.M; 0.016 .mu.M; 0.023 .mu.M; 0.024 .mu.M.
[0173] Examples 21 to 30 showed, respectively, IC.sub.50=0.015
.mu.M; 0.0084 .mu.M; 0.014 .mu.M; 0.013 .mu.M; 0.025 .mu.M; 0.0063
.mu.M; 0.013 .mu.M; 0.017 .mu.M; 0.018 .mu.M; 0.011 .mu.M.
[0174] The ability of the compounds of formula (I), and their
corresponding pharmaceutically-acceptable (acid) salts, to inhibit
DGAT1 may further be demonstrated employing the following whole
cell assay.
Measurement of Triglyceride Synthesis in HuTu 80 Cells
[0175] HuTu80 cells were cultured to confluency in 6 well plates in
minimum essential media containing foetal calf serum. For the
experiment, the medium was changed to serum-free medium and the
cells pre-incubated with compound solubilised in DMSO (final
concentration 0.1%) for 30 minutes. De novo lipogenesis was
measured by the addition of 0.12 mM sodium oleate plus 1 .mu.Ci/mL
.sup.14C-sodium oleate complexed to 0.03 mM BSA to each well for a
further 2 h. The cells were washed in phosphate buffered saline and
solubilised in 1% sodium dodecyl sulfate. An aliquot was removed
for protein determination using a protein estimation kit (Perbio)
based on the method of Lowry (J. Biol. Chem., 1951, 193, 265-275).
The lipids were extracted into the organic phase using a
heptane:propan-2-ol:water (80:20:2) mixture followed by aliquots of
water and heptane according to the method of Coleman (Methods in
Enzymology, 1992, 209, 98-104). The organic phase was collected and
the solvent evaporated under a stream of nitrogen. The extracts
solubilised in iso-hexane: acetic acid (99:1) and lipids separated
via normal phase high performance liquid chromatography (HPLC)
using a Lichrospher diol-5, 4.times.250 mm column and a gradient
solvent system of iso-hexane:acetic acid (99:1) and
iso-hexane:propan-2-ol:acetic acid (85:15:1), flow rate of 1
mL/minute according to the method of Silversand and Haux (1997).
Incorporation of radiolabel into the triglyceride fraction was
analysed using a Radiomatic Flo-one Detector (Packard) connected to
the HPLC machine.
EXAMPLES
[0176] The following examples are for illustration purposes and are
not intended to limit the scope of this application. Each
exemplified compound represents a particular and independent aspect
of the invention. In the following non-limiting Examples, unless
otherwise stated:
(i) evaporations were carried out by rotary evaporation under
reduced pressure and work-up procedures were carried out after
removal of residual solids such as drying agents by filtration;
(ii) operations were carried out at room temperature, that is in
the range 18-25.degree. C. and generally under an atmosphere of an
inert gas such as argon or nitrogen; (iii) yields are given for
illustration only and are not necessarily the maximum attainable;
(iv) the structures of the end-products of the Formula (I) were
confirmed by nuclear (generally proton) magnetic resonance (NMR)
and mass spectral techniques; proton magnetic resonance chemical
shift values were measured on the delta scale and peak
multiplicities are shown as follows: s, singlet; d, doublet; t,
triplet; m, multiplet; br, broad; q, quartet, quin, quintet; (v)
intermediates were not generally fully characterised and purity was
assessed by thin layer chromatography (TLC), high-performance
liquid chromatography (HPLC), infra-red (IR) or NMR analysis; (vi)
flash chromatography was carried out on silica unless otherwise
stated with flash chromatography purifications run on Biotage SP1
or SP4 instruments using Biotage Silica columns; (vii) mass spectra
were recorded on a Finnigan LCQ Duo ion trap mass spectrometer
equipped with an electrospray interface (LC-MS) or LC-MS system
consisting of a Waters ZQ using a LC-Agilent 1100 LC system; (viii)
.sup.1H NMR measurements were performed on a Varian Mercury VXR 300
and 400 spectrometer, operating at a 1H frequency of 300 and 400
and Varian UNITY plus 400, 500 and 600 spectrometers, operating at
1H frequencies of 400, 500 and 600 respectively. Chemical shifts
are given in ppm with the solvent as internal standard. Protons on
heteroatoms such as NH and OH protons are only reported when
detected in NMR and can therefore be missing. (ix) HPLC separations
were performed on a Waters YMC-ODS AQS-3 120 Angstrom 3.times.500
mm or on a Waters Delta Prep Systems using Kromasil C8, 10 .mu.m
columns. Acidic HPLC was carried out using gradients of mobilephase
A: 100% ACN and mobilephase B: 5% ACN+95% H.sub.2O+0.2% FA. Neutral
HPLC was carried out using gradients of mobilephase A: 100% ACN and
mobilephase B: 5% ACN+95% 0.1 M NH.sub.4OAc. (x) Reactions
performed in a microwave oven were run in a Biotage Initiator
Instrument. (xi) Chemical nomenclature software packages, such as
Struc=Name/CambridgeSoft ELN, may have been used in the naming of
compounds.
LIST OF ABBREVIATIONS THAT MAY BE USED HEREIN
[0177] ACN Acetonitrile [0178] aq Aqueous [0179] Boc
tert-butyloxycarbonyl [0180] Brine Saturated solution of sodium
chloride in water [0181] BSA Bovine Serum Albumine [0182] Cbz
Benzylozycarbonyl [0183] DCE 1,2-dichloroethane [0184] DCM
Dichloromethane [0185] DEE Diethylether [0186] DIPEA
N,N-Diisopropylethylamine [0187] DMAP Dimethylaminopyridine [0188]
DMF N,N-dimethylformamide [0189] DMSO Dimethylsulphoxide [0190]
Dppf 1,1'-bis(Diphenylphosphino)ferrocene [0191] EDCI
1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride [0192]
EDTA Ethylenediaminetetraacetic acid [0193] EtOAc Ethyl acetate
[0194] EtOH Ethanol [0195] FA Formic acid [0196] HOAc Acetic acid
[0197] HPLC High-performance liquid chromatography [0198] HWE
Horner-Wadsworth-Emmons [0199] Hz Hertz [0200] IPA Isopropylalcohol
[0201] iPr isopropyl [0202] LC Liquid chromatography [0203] m-CPBA
meta-chloroperoxybenzoicacid [0204] MeOH Methanol [0205] MHz
Megahertz [0206] mL Millilitre [0207] MS Mass spectra [0208] NMM
N-methylmorpholine [0209] NMP N-methylpiperazine [0210] NMR Nuclear
magnetic resonance [0211] OAc acetate [0212] Ph Phenyl [0213] PyBOP
Benzotriazol-1-yl-oxytri-pyrrolidinophosphonium hexafluorophosphate
[0214] PyBROP Bromo-tris-pyrrolidino-phosphonium
Hexafluorophosphate [0215] Ps-Py-SO.sub.3 Polymer supported
pryridine-SO.sub.3 complex [0216] RT Room temperature [0217] sat
saturated [0218] TEA Triethylamine [0219] Tf
trifluoromethylsulfonyl [0220] TFA Trifluoroacetic acid [0221] THF
Tetrahydrofurane [0222] TLC Thin layer chromatography [0223] Ts
p-toluenesulfonyl
Example 1
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetic
acid
##STR00030##
[0225] Powdered potassium hydroxide (45.2 mg, 0.81 mmol) was added
in one portion to methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetat-
e (Intermediate 1-1; 110 mg, 0.27 mmol) in tert-butanol (10 mL) at
45.degree. C. The resulting solution was stirred at 45.degree. C.
for 15 minutes, a thick white suspension slowly formed. 2M HCl (2
mL) was added and the mixture was evaporated to remove the organic
solvent. The suspension was collected by filtration, washed with
water (5 mL) and dried under vacuum to afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetic
acid (82 mg, 77%) as a white solid.
[0226] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.65 (3H, s), 2.76
(3H, s), 3.68 (2H, s), 7.34 (1H, d), 7.43 (1H, d), 7.51 (1H, s),
7.57 (2H, d), 7.61 (1H, s), 7.85 (2H, d), 8.04 (1H, s), 12.45 (1H,
s). m/z (ES+) (M+H)+=396
Intermediate 1-1: Methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetat-
e
##STR00031##
[0228] To a degassed solution of
3,5-dimethyl-6-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pyr-
azine-2-carboxamide (Intermediate 7-6; 196 mg, 0.55 mmol) in DME (6
mL), ethanol (1.5 mL) and water (1.5 mL) was added tripotassium
phosphate (141 mg, 0.67 mmol), methyl
2-(3-chloro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(Intermediate 1-2; 185 mg, 0.55 mmol) followed by
(1,1'-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) (DCM
adduct) (36.5 mg, 0.04 mmol). The resulting mixture was stirred at
80.degree. C. under nitrogen for 4 hours. The reaction mixture was
allowed to cool to ambient temperature, evaporated and partitioned
between EtOAc (75 mL) and saturated brine (50 mL) then filtered
through celite. The organic layer was dried over MgSO.sub.4,
filtered and evaporated to afford crude product. The crude product
was purified by flash silica chromatography, elution gradient 20 to
80% EtOAc in isohexane. Pure fractions were evaporated to dryness
to afford methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetat-
e (110 mg, 48.4%) as a white solid.
[0229] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.65 (3H, s), 2.76
(3H, s), 3.65 (3H, s), 3.79 (2H, s), 7.35 (1H, d), 7.44 (1H, d),
7.53 (1H, s), 7.57 (2H, d), 7.61 (1H, s), 7.85 (2H, d), 8.03 (1H,
s). m/z (ES+) (M+H)+=410
Intermediate 1-2: Methyl
2-(3-chloro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
##STR00032##
[0231] Triethylamine (50.4 mL, 361.88 mmol) was added dropwise to a
stirred solution of methyl 2-(3-chloro-4-hydroxyphenyl)acetate
(24.2 g, 120.63 mmol) and trifluoromethanesulphonic anhydride
(Intermediate 1-3; 29.7 mL, 180.94 mmol) in DCM (500 mL) at
0.degree. C., over a period of 15 minutes under nitrogen. The
resulting solution was stirred at 0.degree. C. for 90 minutes. The
reaction mixture was washed sequentially with saturated NaHCO.sub.3
(300 mL) and saturated brine (300 mL). The organic layer was dried
over MgSO.sub.4, filtered and evaporated to afford crude product.
The crude product was purified by flash silica chromatography,
elution gradient 0 to 20% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford methyl
2-(3-chloro-4-(trifluoromethylsulfonyloxy)phenyl)acetate (36.1 g,
90%) as a yellow oil which solidified on standing.
[0232] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 3.63 (2H, s),
3.73 (3H, s), 7.25-7.28 (1H, m), 7.31 (1H, d), 7.47 (1H, s). m/z
(ES-) (M-H)-=331
Intermediate 1-3: Methyl 2-(3-chloro-4-hydroxyphenyl)acetate
##STR00033##
[0234] A solution of 3-chloro-4-hydroxyphenylacetic acid (24.55 g,
131.57 mmol) and sulfuric acid (0.701 mL, 13.16 mmol) in methanol
(600 mL) was stirred at 75.degree. C. for 3 hours. The reaction
mixture was allowed to cool to ambient temperature evaporated to
dryness and redissolved in EtOAc (500 mL), and washed with
saturated brine (2.times.300 mL). The organic layer was dried over
MgSO.sub.4, filtered and evaporated to afford methyl
2-(3-chloro-4-hydroxyphenyl)acetate (24.20 g, 92%) as a pale yellow
oil.
[0235] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 3.53 (2H, s),
3.70 (3H, s), 5.49 (1H, s), 6.96 (1H, d), 7.07-7.10 (1H, m), 7.26
(1H, s). m/z (ES-) (M-H)-=199
Example 2
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2',6'-difluorobiphen-
yl-4-yl)acetic acid
##STR00034##
[0237] Powdered potassium hydroxide (111 mg, 1.98 mmol) was added
in one portion to methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2',6'-difluorobiphe-
nyl-4-yl)acetate (Intermediate 2-1; 295 mg, 0.66 mmol) in
tert-butanol (10 mL) at 50.degree. C. The resulting solution was
stirred at 50.degree. C. for 45 minutes, 2M HCl (2 mL) was added
and the mixture was evaporated to remove the organic solvent. The
suspension was collected by filtration, washed with water (50 mL)
and air dried to afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2',6'-difluorobiphe-
nyl-4-yl)acetic acid (220 mg, 77%) as a cream solid.
[0238] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.68 (3H, s), 2.78
(3H, s), 3.71 (2H, s), 7.39 (1H, d), 7.48 (1H, d), 7.58 (1H, s),
7.64 (1H, s), 7.71-7.76 (2H, m), 8.16 (1H, s), 12.50 (1H, s). m/z
(ES+) (M+H)+=432
Intermediate 2-1: Methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2',6'-difluorobiphe-
nyl-4-yl)acetate
##STR00035##
[0240] A solution of 6-chloro-3,5-dimethylpyrazine-2-carboxamide
(Intermediate A) (228 mg, 1.23 mmol) and methyl
2-(2-chloro-2',6'-difluoro-4'-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-y-
l)biphenyl-4-yl)acetate (Intermediate 2-2; 521 mg, 1.23 mmol) and
potassium phosphate, tri-basic (314 mg, 1.48 mmol) in DME (15 mL),
MeOH (3.75 mL) and water (3.75 mL) was thoughroughly degassed. The
mixture was treated with PdCl.sub.2(dppf)-DCM adduct (50.3 mg, 0.06
mmol), degassed again and the atmosphere replaced with nitrogen
before being heated to 80.degree. C. for 17 hours. The reaction
mixture was allowed to cool to room temperature and then
evaporated. The crude product was partitioned between EtOAc (75
mL), and 2M HCl (50 mL), the aqueous phase was extracted with a
further 80 mL of EtOAc. The organic extracts were combined, dried
over MgSO.sub.4, filtered and evaporated to afford crude product.
The crude product was purified by flash silica chromatography,
elution gradient 10 to 70% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2',6'-difluorobiphe-
nyl-4-yl)acetate (295 mg, 53.7%) as a white solid.
[0241] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.68 (3H, s), 2.78
(3H, s), 3.67 (3H, s), 3.83 (2H, s), 7.38-7.42 (1H, m), 7.49 (1H,
d), 7.61 (1H, s), 7.64 (1H, s), 7.71-7.76 (2H, m), 8.16 (1H, s).
m/z (ES+) (M+H)+=446
Intermediate 2-2: Methyl
2-(2-chloro-2',6'-difluoro-4'-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-y-
l)biphenyl-4-yl)acetate
##STR00036##
[0243] A solution of methyl
2-(2-chloro-2',6'-difluoro-4'-(trifluoromethylsulfonyloxy)biphenyl-4-yl)a-
cetate (Intermediate 2-3; 675 mg, 1.52 mmol) in dioxane (13.8 mL)
was degassed with nitrogen for a period of 5 minutes. Potassium
acetate (447 mg, 4.55 mmol),
4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(1,3,2-dioxaborolane) (424
mg, 1.67 mmol),
(1,1'-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) (74.9
mg, 0.09 mmol) and 1,1'-bis(diphenylphosphino)ferrocene (51.0 mg,
0.09 mmol) were added and sealed into a microwave tube. The
reaction was heated to 140.degree. C. for 25 minutes in the
microwave reactor and cooled to RT. The reaction mixture was
concentrated and diluted with EtOAc (15 mL), and then mixture was
filtered through silica. The filtrate was evaporated to afford
crude product. The crude product was purified by flash silica
chromatography, elution gradient 0 to 20% EtOAc in isohexane. Pure
fractions were evaporated to dryness to afford methyl
2-(2-chloro-2',6'-difluoro-4'-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-y-
l)biphenyl-4-yl)acetate (521 mg, 81%) as a colourless gum.
[0244] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.36 (12H, s),
3.65 (2H, s), 3.73 (3H, s), 7.26-7.34 (2H, m), 7.37-7.42 (2H, m),
7.46 (1H, s)
Intermediate 2-3: Methyl
2-(2-chloro-2',6'-difluoro-4'-(trifluoromethylsulfonyloxy)biphenyl-4-yl)a-
cetate
##STR00037##
[0246] Methyl
2-(2-chloro-2',6'-difluoro-4'-hydroxybiphenyl-4-yl)acetate
(Intermediate 2-4; 964 mg, 3.08 mmol),
1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide
(1.101 g, 3.08 mmol) and potassium carbonate (1.278 g, 9.25 mmol)
were suspended in THF (15 mL) and sealed into a microwave tube. The
reaction was heated to 120.degree. C. for 8 minutes in the
microwave reactor and cooled to RT. The suspension was filtered,
the solid was washed with EtOAc (20 mL) and the filtrate was
evaporated to afford crude product. The crude product was purified
by flash silica chromatography, elution gradient 0 to 10% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
methyl
2-(2-chloro-2',6'-difluoro-4'-(trifluoromethylsulfonyloxy)biphenyl-4-yl)a-
cetate (675 mg, 49.2%) as a pale yellow oil.
[0247] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 3.67 (2H, s),
3.74 (3H, s), 6.97-7.03 (2H, m), 7.28-7.30 (1H, m), 7.37-7.40 (1H,
m), 7.48 (1H, s). m/z (ES-) (M-H)-=443
Intermediate 2-4: Methyl
2-(2-chloro-2',6'-difluoro-4'-hydroxybiphenyl-4-yl)acetate
##STR00038##
[0249] Boron tribromide (1.494 mL, 15.80 mmol) was added dropwise
to 2-(2-chloro-2',6'-difluoro-4'-methoxybiphenyl-4-yl)acetic acid
(Intermediate 2-5; 822 mg, 2.63 mmol) in dichloromethane (30 mL) at
ambient temperature under nitrogen. The resulting solution was
stirred at ambient temperature for 90 minutes. The reaction mixture
was cautiously added to ice water cooled methanol (50 mL) and the
mixture was stirred for a further 20 minutes. The reaction mixture
was evaporated to dryness and redissolved in EtOAc (150 mL), and
washed sequentially with 2M HCl (50 mL) and saturated brine (50
mL). The organic layer was dried over MgSO.sub.4, filtered and
evaporated to afford methyl
2-(2-chloro-2',6'-difluoro-4'-hydroxybiphenyl-4-yl)acetate (822 mg,
100%) as a yellow gum.
[0250] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 3.65 (2H, s),
3.74 (3H, s), 6.46-6.51 (2H, m), 7.15-7.19 (1H, m), 7.26-7.30 (2H,
m). m/z (ES-) (M-H)-=311
Intermediate 2-5:
2-(2-Chloro-2',6'-difluoro-4'-methoxybiphenyl-4-yl)acetic acid
##STR00039##
[0252] A solution of 4-bromo-3,5-difluoroanisole (645 mg, 2.89
mmol) and 2-chloro-4-(2-methoxy-2-oxoethyl)phenylboronic acid
(Intermediate 2-6; 859 mg, 3.76 mmol) and sodium carbonate (2.89
mL, 5.78 mmol), tetrakis(triphenylphosphine)palladium(0) (207 mg,
0.18 mmol) in DME (20 mL) was degassed and then stirred at
85.degree. C. for 17 hours. The reaction mixture was allowed to
cool, evaporated and partitioned between EtOAc (75 mL), water (40
mL) and saturated brine (15 mL), The aqueous phase was acidified
with 2M HCl and extracted into EtOAc (2.times.125 mL). The organic
layer was dried over MgSO.sub.4, filtered and evaporated to afford
2-(2-chloro-2',6'-difluoro-4'-methoxybiphenyl-4-yl)acetic acid (654
mg, 72.4%) as a white solid, which was used without further
purification.
[0253] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 3.67 (2H, s),
3.83 (3H, s), 6.52-6.56 (2H, m), 7.15-7.20 (1H, m), 7.28-7.30 (1H,
m), 7.46 (1H, s). m/z GCMS (ES-) (M-H)-=311
Intermediate 2-6: 2-Chloro-4-(2-methoxy-2-oxoethyl)phenylboronic
acid
##STR00040##
[0255] Sodium periodate (1.967 g, 9.20 mmol) and ammonium acetate
(0.709 g, 9.20 mmol) were added to a stirred solution of methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)acetate
(Intermediate 2-7; 0.952 g, 3.07 mmol) in acetone (20 mL) and water
(10 mL). The resulting suspension was stirred at ambient
temperature for 17 hours. The reaction mixture was diluted with
water (50 mL) and extracted with EtOAc (3.times.250 mL). The
organic extracts were combined washed with saturated brine (100
mL), dried over MgSO.sub.4, filtered and evaporated to afford
2-chloro-4-(2-methoxy-2-oxoethyl)phenylboronic acid (0.656 g, 94%)
as a cream oil which solidified on standing, and was used without
further purification.
[0256] .sup.1H NMR (400.132 MHz, DMSO) .delta. 3.61 (3H, s), 3.68
(2H, s), 7.14-7.17 (1H, m), 7.26 (1H, s), 7.35 (1H, d), 8.24 (2H,
s)
Intermediate 2-7: Methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)acetate
##STR00041##
[0258] To a degassed solution of methyl
2-(3-chloro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(Intermediate 1-2; 6.56 g, 19.72 mmol) in dioxane (150 mL) was
added potassium acetate (6.00 g, 61.13 mmol),
bis(pinacolato)diboron (7.51 g, 29.58 mmol),
1,1'-bis(diphenylphosphino)ferrocene (0.663 g, 1.18 mmol) and
PdCl.sub.2(dppf)-CH.sub.2Cl.sub.2 adduct (0.966 g, 1.18 mmol). The
suspension was degassed and then heated, under nitrogen, to
100.degree. C. overnight. The reaction was incomplete and further
PdCl.sub.2(dppf)-CH.sub.2Cl.sub.2 adduct (0.966 g, 1.18 mmol) was
added and the mixture was stirred at 100.degree. C. for a further 4
hours. The reaction mixture was allowed to cool, concentrated and
diluted with EtOAc (300 mL), and washed with saturated brine (300
mL). The organic layer was dried over MgSO.sub.4, filtered and
evaporated to afford crude product which was filtered through a pad
of silica (1''.times.3''), washing through with EtOAc. The crude
product was purified by flash silica chromatography, elution
gradient 0 to 20% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)acetate
(6.11 g, 100%) as a colourless oil which solidified on
standing.
[0259] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.36 (12H, s),
3.59 (2H, s), 3.68 (3H, s), 7.14-7.16 (1H, m), 7.28 (1H, s), 7.65
(1H, d).
Intermediate A: 6-Chloro-3,5-dimethylpyrazine-2-carboxamide
##STR00042##
[0261] Intermediate A-1 (227 g, 1057.54 mmol) was stirred in
ammonia (7N in MeOH) (1957 mL, 89633.59 mmol) at ambient
temperature overnight. The mixture was evaporated to dryness and
the residue was triturated with ether and the suspension was
filtered and at 40.degree. C. under vacuum to afford the title
compound (181 g, 92%) as a light brown solid.
[0262] .sup.1H NMR (400 MHz, DMSO) .delta. 2.59 (3H, s), 2.67 (3H,
s), 7.70 (1H, s), 7.99 (1H, s) m/z 186 (M+H).sup.+.
Intermediate A-1: Ethyl
6-chloro-3,5-dimethylpyrazine-2-carboxylate
##STR00043##
[0264] To a suspension of Intermediate A-2 (0.23 g, 1.17 mmol) in
butyronitrile (4 mL) was added POCl.sub.3 (0.27 mL, 2.93 mmol). The
reaction was heated to 150.degree. C. for 10 min in the microwave
oven and cooled to RT. To the reaction mixture was added water (2
mL) and the phases were separated. The organic layer was
concentrated under reduced pressure. The crude product was purified
by flash chromatography using 0.5% HOAc in DCM as eluent to afford
the title compound (0.18 g, 73%).
[0265] .sup.1H NMR (500 MHz, CDCl.sub.3) .delta. 1.43 (t, 3H), 2.68
(s, 3H), 2.78 (s, 3H), 4.46 (q, 2H); m/z 215 (M+H).sup.+.
Intermediate A-2: Ethyl
3,5-dimethyl-6-oxo-1,6-dihydropyrazine-2-carboxylate
##STR00044##
[0267] To a solution of Intermediate A-3 (800 mg, 2.53 mmol) in dry
DCE (40 mL) was added TFA (1.95 mL, 25.3 mmol). The reaction
mixture was heated to reflux for 4 h. The solvent was evaporated
and the crude product was purified by flash chromatography using
EtOAc (20-80%) in heptane as eluent. Concentration of pure
fractions gave title compound (160 mg, 32%) as white-yellow powder.
The crude from this reaction can optionally be used directly in the
next step without purification.
[0268] .sup.1H NMR (400 Mhz, CDCl.sub.3) .delta. 4.42 (q, 2H), 2.61
(s, 3H), 2.52 (s, 3H), 1.41 (t, 3H); m/z 197 (M+H).sup.+.
Intermediate A-3: Ethyl
2-{[N-(tert-butoxycarbonyl)-L-alanyl]amino}-3-oxobutanoate
##STR00045##
[0270] Intermediate A-4 (500 mg, 3.2 mmol) and BOC-Ala-NH.sub.2
(843.8 mg, 4.5 mmol, CAS 85642-13-3) were added to a round bottomed
flask, sealed and backfilled with argon. Dry toluene (30 mL) was
added via syringe and the resulting heterogeneous mixture was
stirred at 90.degree. C. for 10 min to get a homogeneous solution.
Meanwhile, the rhodium (II) octanoate dimer (62.3 mg, 0.080 mmol,
CAS 73482-96-9) was dissolved in toluene (5 mL) and put on an
ultrasound bath for 5 min, to get a fine Rh-dispersion. This
dispersion was then added dropwise to the reaction mixture at
80.degree. C. (a violent N.sub.2 effervescence was observed).
[0271] After stirring another 20 min at elevated temperature the
reaction mixture was concentrated under reduced pressure to give a
black pasty solid. The N--H insertion product could here be
purified or taken directly to the next step. The crude was purified
by flash chromatography using EtOAc (20-80%) in heptane to afford
the title compound (850 mg, 84%) (diastereomeric mixture) as a
yellow oil. m/z 317 (M+H).sup.+.
Intermediate A-4: Ethyl 2-diazo-3-oxobutanoate
##STR00046##
[0273] Polymer-bound tosylazide (11 g, 15.4 mmol) (typical loading
1,4 mmol/g, prepared according to Merz et al J. Org. Chem. 2001,
66, 2509-2511) was swollen in dry DCM (40 mL). Ethyl acetoacetate
(1.0 g, 7.7 mmol, CAS 141-97-9) and TEA (3.2 mL, 23.1 mmol) were
dissolved in DCM (10 mL) and added to the polymer containing
solution. The resulting mixture was then shaken at RT under
nitrogen until the reaction was judged completed by TLC, typically
6 h. The supernatant was filtered off, then the resin was washed
with DCM (3.times.30 mL) to rinse out residual product. The
reaction mixture was then evaporated to dryness to afford the title
compound (1.1 g, 92%) as yellow oil.
[0274] .sup.1H NMR (400 MHz, CDCl.sub.3) .delta. 4.28 (q, 2H), 2.45
(s, 3H), 1.33 (t, 3H).
[0275] Typically these intermediates were not characterized due to
their high-energetic properties (Clark et al, Thermochimica Acta,
386, 2002, 73-79), but carried through to the next step as crude
products.
Alternative Preparations
Intermediate A-1: Ethyl
6-chloro-3,5-dimethylpyrazine-2-carboxylate
##STR00047##
[0277] A suspension of Intermediate A-2 (268 g, 1365.93 mmol) in
phosphorus oxychloride (1273 mL, 13659.31 mmol) was heated at
90.degree. C. under nitrogen for 1 hour then cooled to ambient
temperature. The reaction was cautiously added to water (6 L) with
vigorous stirring keeping the temperature between 17.degree. C. and
20.degree. C. The mixture was then extracted with DCM (5.times.2.5
L), washed with water, saturated brine and dried over MgSO.sub.4
and evaporated to afford crude product. The crude product was
purified by flash silica chromatography, elution gradient 0 to 25%
EtOAc in isohexane. Pure fractions were evaporated to dryness to
afford the title compound (227 g, 77%) as a yellow oil which
solidified on standing.
[0278] .sup.1H NMR (400 MHz, CDCl.sub.3) .delta. 1.43 (3H, t), 2.68
(3H, s), 2.77 (3H, s), 4.46 (2H, q); m/z 215 (M+H).sup.+.
Intermediate A-2: Ethyl
6-hydroxy-3,5-dimethylpyrazine-2-carboxylate
##STR00048##
[0280] A solution of 2M Hydrochloric acid in 1,4-dioxane (1177 mL,
4709.97 mmol) was added to Intermediate A-3 (745 g, 2354.99 mmol)
and stirred at room temperature for 15 minutes then warmed to
40.degree. C. for a further 40 minutes. Pyridine (6500 mL) was then
slowly added and then the reaction was heated to 80.degree. C. for
2 hours in the presence of air. The reaction was then allowed to
cool to ambient temperature and evaporated to dryness to afford a
viscous oil. This was suspended in DCM (2.5 L) and washed water
(1.5 L). The DCM was then dried over MgSO.sub.4, filtered and
concentrated to afford an orange semi-solid, which was triturated
with 1:1 EtOAc/iso-hexane (250 mL) to afford ethyl
6-hydroxy-3,5-dimethyl-1,4-dihydropyrazine-2-carboxylate (127 g,
27.1%) as a cream solid. The mother liqours were then purified by
flash silica chromatography (gradient from 20% ethyl
acetate/iso-hexane to 80% ethyl acetate/iso-hexane). Fractions
containing the desired product were concentrated and the residue
was triturated with a small volume of 1:1 EtOAc/iso-hexane to
afford the title compound (9.00 g, 1.948%).
[0281] Manganese dioxide (150 g) was added to a suspension of ethyl
6-hydroxy-3,5-dimethyl-4,5-dihydropyrazine-2-carboxylate (121 g,
610.44 mmol) in DCM (1.8 L) at ambient temperature giving rise to a
2.degree. C. exotherm. The reaction was stirred for 10 minutes then
warmed to 35.degree. C. for 1 hour. The reaction was incomplete so
an additional 115 g of Manganese dioxide was added and the reaction
stirred for 1 hour at 35.degree. C. then stirred to cool to ambient
temperature. The reaction was filtered through a short bed of
silica and washed through with 2 L of 1:1 EtOAc/iso-hexane and
finally 2.times.2 L EtOAc. The fractions were then combined and
reduce in-vacuo to give an orange solid, which was slurried in 300
mL of 1:1 EtOAc/iso-hexane, filtered and washed with iso-hexane to
afford the title compound (87 g, 72.6%) as an orange solid.
[0282] .sup.1H NMR (400 MHz, DMSO) .delta. 1.31 (3H, t), 2.35 (3H,
s), 2.50 (3H, s), 4.31 (2H, q), 11.93 (1H, s); m/z 197
(M+H).sup.+
[0283] Intermediate A-3 can also be prepared by the following
procedure:
Intermediate A-3: Ethyl
2-(2-(tert-butoxycarbonylamino)propanamido)-3-oxobutanoate
##STR00049##
[0285] A solution of 4-methylmorpholine (900 g) in THF (15 L) was
added to 2-(tert-butoxycarbonylamino)propanoic acid (1690 g,
8933.17 mmol). The mixture was cooled to -25.degree. C. and
isobutyl chloroformate (1.164 L, 8933.17 mmol) was added. After 20
minutes the second equivalent of 4-methylmorpholine (900 g) was
added followed by ethyl 2-amino-3-oxobutanoate Tosylate salt (see
J-P. Genet et al, Eur. J. Org. Chem., 2004, 3017-3026) (2700 g,
8507.78 mmol) suspended in THF (2.5 L). The mixture was stirred at
-25.degree. C. for 30 minutes and then left to warm to ambient
temperature overnight. The reaction was quenched with water (15 L),
extracted with EtOAc (3.times.5 L) and the combined extracts washed
with 50% saturated brine (5 L). The organic layer was dried over
MgSO.sub.4, filtered and evaporated to afford crude product. The
crude product was purified by flash silica chromatography, elution
gradient 50 to 80% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford ethyl
2-(2-(tert-butoxycarbonylamino)propanamido)-3-oxobutanoate (1850 g,
68.7%).
Example 3
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-5-methylbiphenyl-4-y-
l)acetic acid
##STR00050##
[0287] Powdered potassium hydroxide (88 mg, 1.56 mmol) was added in
one portion to ethyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-5-methylbiphenyl-4--
yl)acetate (Intermediate 3-1; 228 mg, 0.52 mmol) in tert-butanol
(15 mL) at 55.degree. C. The resulting mixture was stirred at
55.degree. C. for 45 minutes, 2M HCl (.about.1 mL) was added and
the mixture was evaporated to remove the organic solvent. The
suspension was collected by filtration, washed with water (20 mL)
and air dried to afford crude product as a pale yellow solid, which
contained a minor impurity. The crude product was purified by
preparative HPLC (Waters XBridge Prep C18 OBD column, 5.mu. silica,
50 mm diameter, 150 mm length), using decreasingly polar mixtures
of water (containing 0.1% formic acid) and MeCN as eluents.
Fractions containing the desired compound were evaporated to
dryness to afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-5-methylbiphenyl-4--
yl)acetic acid (193 mg, 90%) as a cream solid.
[0288] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.27 (3H, s), 2.64
(3H, s), 2.76 (3H, s), 3.67 (2H, s), 7.30 (1H, s), 7.43 (1H, s),
7.57 (2H, d), 7.61 (1H, s), 7.84 (2H, d), 8.04 (1H, s), 12.46 (1H,
s). m/z (ES+) (M+H)+=410
Intermediate 3-1: Ethyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-5-methylbiphenyl-4--
yl)acetate
##STR00051##
[0290] A solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenylboronic acid
(Intermediate 5-1; 284 mg, 1.05 mmol) and ethyl
2-(5-chloro-2-methyl-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(Intermediate 3-2; 336 mg, 0.93 mmol) and 2M sodium carbonate
(0.757 mL, 1.51 mmol), tetrakis(triphenylphosphine)palladium(0)
(66.7 mg, 0.06 mmol) and lithium chloride (69.1 mg, 1.63 mmol) in
DME (20 mL) and ethanol (5 mL) was degassed and then stirred at
85.degree. C. After 4 hours further
tetrakis(triphenylphosphine)palladium(0) (100 mg) and 2M sodium
carbonate (0.5 mL) were added and heating was continued for a
further 17 hours (overnight). The reaction mixture was allowed to
cool, evaporated and partitioned between EtOAc (100 mL), water (50
mL) and 2M HCl (10 mL). The aqueous phase was re-extracted with
EtOAc (100 mL), the combined organic extracts were dried over
MgSO.sub.4, filtered and evaporated to afford crude product. The
crude product was purified by flash silica chromatography, elution
gradient 0 to 50% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford ethyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-5-methylbiphenyl-4--
yl)acetate (288 mg, 70.6%) as a yellow solid.
[0291] .sup.1H NMR (400.132 MHz, DMSO) .delta. 1.21 (3H, t), 2.26
(3H, s), 2.65 (3H, s), 2.76 (3H, s), 3.76 (2H, s), 4.12 (2H, q),
7.32 (1H, s), 7.45 (1H, s), 7.57 (2H, d), 7.61 (1H, s), 7.84 (2H,
d), 8.04 (1H, s). m/z (ES+) (M+H)+=438
Intermediate 3-2: Ethyl
2-(5-chloro-2-methyl-4-(trifluoromethylsulfonyloxy)phenyl)acetate
##STR00052##
[0293] Ethyl 2-(5-chloro-4-hydroxy-2-methylphenyl)acetate
(Intermediate 3-3; 310 mg, 1.36 mmol),
1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide
(484 mg, 1.36 mmol) and potassium carbonate (562 mg, 4.07 mmol)
were suspended in THF (10 mL) and sealed into a microwave tube. The
reaction was heated to 120.degree. C. for 8 minutes in the
microwave reactor and cooled to RT. The suspension was filtered,
the solid was washed with EtOAc (20 mL) and the filtrate was
evaporated to afford crude product. The crude product was purified
by flash silica chromatography, elution gradient 0 to 20% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
ethyl
2-(5-chloro-2-methyl-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(336 mg, 68.7%) as a white solid.
[0294] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.27 (3H, t),
2.32 (3H, s), 3.60 (2H, s), 4.17 (2H, q), 7.16 (1H, s), 7.36 (1H,
s). m/z (ES-) (M-H)-=359
Intermediate 3-3: Ethyl
2-(5-chloro-4-hydroxy-2-methylphenyl)acetate
##STR00053##
[0296] Boron tribromide (1.068 mL, 11.30 mmol) was added dropwise
to ethyl 2-(5-chloro-4-methoxy-2-methylphenyl)acetate (Intermediate
3-4; 456 mg, 1.88 mmol) in dichloromethane (10 mL) at ambient
temperature under nitrogen. The resulting orange red solution was
stirred at 0.degree. C. for 45 minutes. The reaction mixture was
carefully quenched with water (25 mL), extracted with EtOAc
(2.times.100 mL), the organic layer was dried over MgSO.sub.4,
filtered and evaporated to afford crude product as a yellow gum.
The crude product was purified by flash silica chromatography,
elution gradient 0 to 20% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford ethyl
2-(5-chloro-4-hydroxy-2-methylphenyl)acetate (310 mg, 72.2%) as a
colourless oil which solidified on standing.
[0297] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.25 (3H, t),
2.24 (3H, s), 3.51 (2H, s), 4.15 (2H, q), 5.40 (1H, s), 6.84 (1H,
s), 7.15 (1H, s). m/z (ES-) (M-H)-=227
Intermediate 3-4:Ethyl
2-(5-chloro-4-methoxy-2-methylphenyl)acetate
##STR00054##
[0299] Iron powder (193 mg, 3.46 mmol) was added to a stirred
solution of ethyl
2-chloro-2-(5-chloro-4-methoxy-2-methylphenyl)acetate (Intermediate
3-5; 480 mg, 1.73 mmol) in AcOH (2 mL) under nitrogen, and the
resulting mixture was stirred at 60.degree. C. for 17 hours. The
reaction mixture was allowed to cool to ambient temperature,
diluted with EtOAc (50 mL), filtered through celite and washed with
saturated brine (3.times.25 mL). The organic layer was dried over
MgSO.sub.4, filtered and evaporated to afford crude product. The
crude product was purified by flash silica chromatography, elution
gradient 0 to 20% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford ethyl
2-(5-chloro-4-methoxy-2-methylphenyl)acetate (190 mg, 45.2%) as a
colourless gum.
[0300] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.25 (3H, t),
2.28 (3H, s), 3.52 (2H, s), 3.88 (3H, s), 4.15 (2H, q), 6.74 (1H,
s), 7.19 (1H, s). m/z GCMS (EI+) M+=242
Intermediate 3-5: Ethyl
2-chloro-2-(5-chloro-4-methoxy-2-methylphenyl)acetate
##STR00055##
[0302] A solution of ethyl
2-(5-chloro-4-methoxy-2-methylphenyl)-2-hydroxyacetate
(Intermediate 3-6; 1.1 g, 4.25 mmol) in thionyl chloride (3.42 mL,
46.89 mmol) under nitrogen was stirred at 80.degree. C. for 30
minutes. The reaction mixture was allowed to cool concentrated and
diluted with water (20 mL), extracted with EtOAc (2.times.20 mL),
the organic layer was dried over MgSO.sub.4, filtered and
evaporated to afford ethyl
2-chloro-2-(5-chloro-4-methoxy-2-methylphenyl)acetate (1.170 g,
99%) as a yellow gum.
[0303] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.27 (3H, t),
2.40 (3H, s), 3.89 (3H, s), 4.20-4.30 (2H, m), 5.50 (1H, s), 6.73
(1H, s), 7.52 (1H, s)
Intermediate 3-6: Ethyl
2-(5-chloro-4-methoxy-2-methylphenyl)-2-hydroxyacetate
##STR00056##
[0305] A solution of ethyl
2-(5-chloro-4-methoxy-2-methylphenyl)-2-oxoacetate (Intermediate
3-7; 6.12 g, 23.84 mmol) in warm AcOH (60 mL) was added to a
stirred suspension of zinc dust (7.80 g, 119.21 mmol) in AcOH (20
mL) and the resulting suspension was stirred at ambient temperature
for 16 hours. The reaction mixture was filtered, the filtrate
diluted with EtOAc (200 mL), and washed with saturated brine
(3.times.125 mL). The organic layer was dried over MgSO.sub.4,
filtered and evaporated to afford ethyl
2-(5-chloro-4-methoxy-2-methylphenyl)-2-hydroxyacetate (5.70 g,
92%) as a pale yellow oil which solidified on standing, which was
used without further purification.
[0306] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.23 (3H, t),
2.40 (3H, s), 3.89 (3H, s), 4.15-4.31 (2H, m), 5.25 (1H, s), 6.73
(1H, s), 7.30 (1H, s); OH not seen.
Intermediate 3-7: Ethyl
2-(5-chloro-4-methoxy-2-methylphenyl)-2-oxoacetate
##STR00057##
[0308] Ethyl 2-chloro-2-oxoacetate (6.43 mL, 57.47 mmol) was added
dropwise to a stirred suspension of aluminum trichloride (7.66 g,
57.47 mmol) in DCM (60 mL) at 0.degree. C., over a period of 5
minutes under nitrogen. The resulting suspension was stirred at
0.degree. C. for 15 minutes. A solution of
1-chloro-2-methoxy-4-methylbenzene (5 g, 31.93 mmol) in DCM (50 mL)
was added dropwise over a period of 5 minutes and the resulting
mixture was stirred at 0.degree. C. for 90 minutes. The reaction
mixture was cautiously quenched with water (300 mL) at 0.degree.
C., extracted with EtOAc (2.times.200 mL), the organic layers were
combined, dried over MgSO.sub.4, filtered and evaporated to afford
cream solid. The crude solid was triturated with DCM to give a
solid which was collected by filtration and dried under vacuum to
give ethyl 2-(5-chloro-4-methoxy-2-methylphenyl)-2-oxoacetate (4.27
g) as a white solid. The residue was purified by flash silica
chromatography, elution gradient 0 to 20% EtOAc in isohexane. Pure
fractions were evaporated to dryness to afford ethyl
2-(5-chloro-4-methoxy-2-methylphenyl)-2-oxoacetate (1.85 g,) as a
white solid. Total yield of ethyl
2-(5-chloro-4-methoxy-2-methylphenyl)-2-oxoacetate (6.12 g,
74.7%).
[0309] .sup.1H NMR (400.132 MHz, DMSO) .delta. 1.30 (3H, t), 2.53
(3H, s), 3.97 (3H, s), 4.38 (2H, q), 7.22 (1H, s), 7.76 (1H, s)
Example 4
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2,5-dichlorobiphenyl-4-yl)ace-
tic acid
##STR00058##
[0311] Powdered potassium hydroxide (56.1 mg, 1.00 mmol) was added
in one portion to methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,5-dichlorobiphenyl-4-yl)ac-
etate (Intermediate 4-1; 148 mg, 0.33 mmol) in tert-butanol (10 mL)
at 55.degree. C. The resulting solution was stirred at 55.degree.
C. for 45 minutes, 2M HCl (2 mL) was added and the mixture was
evaporated to remove the organic solvent. The suspension was
collected by filtration, washed with water (50 mL) and air dried to
afford crude product as a pale yellow solid, which contained a
minor impurity. The crude product was purified by preparative HPLC
(Waters XBridge Prep C18 OBD column, 5.mu. silica, 50 mm diameter,
150 mm length), using decreasingly polar mixtures of water
(containing 0.1% formic acid) and MeCN as eluents. Fractions
containing the desired compound were evaporated to dryness to
afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,5-dichlorobiphenyl-4-yl)ac-
etic acid (79 mg, 55.2%) as a white solid.
[0312] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.65 (3H, s), 2.76
(3H, s), 3.80 (2H, s), 7.57-7.62 (4H, m), 7.70 (1H, s), 7.87 (2H,
d), 8.04 (1H, s), 12.62 (1H, s). m/z (ES+) (M+H)+=430
Intermediate 4-1: Methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,5-dichlorobiphenyl-4-yl)ac-
etate
##STR00059##
[0314] A solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenylboronic acid
(Intermediate 5-1; 312 mg, 1.15 mmol) and methyl
2-(2,5-dichloro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(Intermediate 4-2; 375 mg, 1.02 mmol) and 2M sodium carbonate
(0.830 mL, 1.66 mmol), tetrakis(triphenylphosphine)palladium(0)
(73.2 mg, 0.06 mmol) and lithium chloride (76 mg, 1.79 mmol) in DME
(10 mL) was degassed and then stirred at 85.degree. C. for 17
hours. The reaction mixture was concentrated and diluted with EtOAc
(75 mL), and washed sequentially with 2M HCl (25 mL) and saturated
brine (25 mL). The organic layer was dried over MgSO.sub.4,
filtered and evaporated to afford crude product. The crude product
was purified by flash silica chromatography, elution gradient 0 to
50% EtOAc in isohexane. Pure fractions were evaporated to dryness
to afford methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,5-dichlorobiphenyl-4-yl)ac-
etate (148 mg, 32.6%) as a yellow solid.
[0315] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.64 (3H, s), 2.76
(3H, s), 3.67 (3H, s), 3.91 (2H, s), 7.59-7.63 (4H, m), 7.73 (1H,
s), 7.87 (2H, d), 8.03 (1H, s). m/z (ES+) (M+H)+=444
Intermediate 4-2: Methyl
2-(2,5-dichloro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
##STR00060##
[0317] Methyl 2-(2,5-dichloro-4-hydroxyphenyl)acetate (Intermediate
4-3; 258 mg, 1.10 mmol),
1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide
(392 mg, 1.10 mmol) and potassium carbonate (455 mg, 3.29 mmol)
were suspended in THF (10 mL) and sealed into a microwave tube. The
reaction was heated to 120.degree. C. for 8 minutes in the
microwave reactor and cooled to RT. The suspension was filtered,
the solid was washed with EtOAc (20 mL) and the filtrate was
evaporated to afford crude product. The crude product was purified
by flash silica chromatography, elution gradient 0 to 20% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
methyl 2-(2,5-dichloro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(375 mg, 93%) as a pale yellow oil.
[0318] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 3.75 (3H, s),
3.77 (2H, s), 7.42 (1H, s), 7.50 (1H, m/z (ES-) (M-H)-=365
Intermediate 4-3: Methyl
2-(2,5-dichloro-4-hydroxyphenyl)acetate
##STR00061##
[0320] Boron tribromide (1.581 mL, 16.72 mmol) was added dropwise
to 2-(2,5-dichloro-4-methoxyphenyl)acetic acid (Intermediate 4-4;
655 mg, 2.79 mmol) in dichloromethane (20 mL) at ambient
temperature under nitrogen. The resulting solution was stirred at
ambient temperature for 60 minutes. The reaction mixture was
cautiously added to methanol (100 mL) (--care reaction is vigorous
and exothermic--mixture became reasonably warm during the addition)
and the mixture was stirred for a further 2 hours at ambient
temperature. The reaction mixture was evaporated to dryness and
redissolved in DCM (100 mL), and washed sequentially with 2M HCl
(50 mL) and saturated brine (50 mL). The organic layer was dried
over MgSO4, filtered and evaporated to afford crude product. The
crude product was purified by flash silica chromatography, elution
gradient 0 to 20% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford methyl
2-(2,5-dichloro-4-hydroxyphenyl)acetate (258 mg, 39.4%) as a pale
yellow solid.
[0321] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 3.67 (2H, s),
3.72 (3H, s), 5.62 (1H, s), 7.07 (1H, s), 7.26 (1H, s). m/z (ES-)
(M-H)-=233
Intermediate 4-4: 2-(2,5-Dichloro-4-methoxyphenyl)acetic acid
##STR00062##
[0323] A solution of diethyl
2-(2,5-dichloro-4-methoxyphenyl)malonate (Intermediate 4-5; 1.88 g,
5.61 mmol) in THF (55 mL) and EtOH (5 mL) was treated with 2M
sodium hydroxide (11.22 mL, 22.44 mmol) in one portion and the
resulting solution was stirred at 60.degree. C. for 17 hours. The
reaction mixture was evaporated and the aqueous residue was
acidified with 2M HCl. The precipitate was collected by filtration,
washed with water (25 mL) and dried under vacuum to afford
2-(2,5-dichloro-4-methoxyphenyl)acetic acid (0.800 g, 60.7%) as a
grey solid, which was used without further purification.
[0324] .sup.1H NMR (400.132 MHz, DMSO) .delta. 3.64 (2H, s), 3.87
(3H, s), 7.23 (1H, s), 7.49 (1H, s), 12.43 (1H, s). m/z (ES-)
(M-H)-=233
Intermediate 4-5: Diethyl
2-(2,5-dichloro-4-methoxyphenyl)malonate
##STR00063##
[0326] A solution of 1-bromo-2,5-dichloro-4-methoxybenzene
(Intermediate 4-6; 3.82 g, 14.93 mmol), cesium carbonate (14.59 g,
44.78 mmol) and
dicyclohexyl(2',4',6'-triisopropylbiphenyl-2-yl)phosphine (0.427 g,
0.90 mmol) in toluene (220 mL) was thoughroughly degassed. The
mixture was treated with diacetoxypalladium (0.101 g, 0.45 mmol)
and diethyl malonate (2.505 mL, 16.42 mmol) and the resulting
solution stirred under a nitrogen atmosphere at 100.degree. C. for
18 hours. The reaction mixture was allowed to cool to ambient
temperature, evaporated to dryness and partitioned between EtOAc
(150 mL) and water (100 mL). The mixture was filtered and the
aqueous layer was separated and re extracted with EtOAc (150 mL).
The organic extracts were combined, dried over MgSO.sub.4, filtered
and evaporated to afford crude product. The crude product was
purified by flash silica chromatography, elution gradient 0 to 20%
EtOAc in isohexane. Pure fractions were evaporated to dryness to
afford diethyl 2-(2,5-dichloro-4-methoxyphenyl)malonate (1.880 g,
37.6%) as a yellow oil.
[0327] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.28 (6H, t),
3.89 (3H, s), 4.21 (4H, q), 5.09 (1H, s), 6.96 (1H, s), 7.53 (1H,
s). m/z (ES-) (M-H)-=335
Intermediate 4-6: 1-Bromo-2,5-dichloro-4-methoxybenzene
##STR00064##
[0329] Methyl iodide (1.861 mL, 29.76 mmol) was added to a stirred
suspension of 4-bromo-2,5-dichlorophenol (4.8 g, 19.84 mmol) and
potassium carbonate (8.23 g, 59.53 mmol) in DMF (20 mL) at ambient
temperature under air. The resulting suspension was stirred at
50.degree. C. for 90 minutes. The reaction mixture was allowed to
cool and diluted with EtOAc (200 mL), and washed sequentially with
saturated brine (2.times.150 mL) and water (100 mL). The organic
layer was dried over MgSO.sub.4, filtered and evaporated to afford
crude product. The crude product was purified by flash silica
chromatography, elution gradient 0 to 20% EtOAc in isohexane. Pure
fractions were evaporated to dryness to afford
1-bromo-2,5-dichloro-4-methoxybenzene (3.82 g, 75%) as a brown
solid.
[0330] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 3.89 (3H, s),
7.02 (1H, s), 7.59 (1H, s)
Example 5
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-(trifluoromethyl)biphenyl-4-
-yl)acetic acid
##STR00065##
[0332] A solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenylboronic acid
(Intermediate 5-1; 278 mg, 1.02 mmol) and methyl
2-(3-(trifluoromethyl)-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(Intermediate 5-2; 300 mg, 0.82 mmol) and sodium carbonate (0.666
mL, 1.33 mmol), tetrakis(triphenylphosphine)palladium(0) (58.7 mg,
0.05 mmol) and lithium chloride (60.8 mg, 1.43 mmol) in DME (20 mL)
was degassed and then stirred at 85.degree. C. for 17 hours. The
reaction mixture was The reaction mixture was acidified with 2M HCl
and evaporated. The precipitate was collected by filtration, washed
with water (20 mL) and dried under vacuum to afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-(trifluoromethyl)biphenyl--
4-yl)acetic acid (197 mg, 55.9%) as a brown solid, which was
purified by flash silica chromatography, elution gradient 0 to 6%
MeOH in DCM. Failed to purify material so was further purified by
preparative HPLC (Waters XBridge Prep C18 OBD column, 5.mu. silica,
50 mm diameter, 150 mm length), using decreasingly polar mixtures
of water (containing 1% formic acid) and MeCN as eluents. Fractions
containing the desired compound were evaporated to dryness to
afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-(trifluoromethyl)biphenyl--
4-yl)acetic acid (197 mg, 55.9%) as a white solid.
[0333] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.64 (3H, s), 2.75
(3H, s), 3.79 (2H, s), 7.41-7.46 (3H, m), 7.62-7.64 (2H, m), 7.77
(1H, s), 7.83 (2H, d), 8.04 (1H, s), 12.51 (1H, s). m/z (ES+)
(M+H)+=430
Intermediate 5-1:
4-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)phenylboronic acid
##STR00066##
[0335] Sodium periodate (19.64 g, 91.81 mmol) was added in one
portion to
3,5-dimethyl-6-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pyr-
azine-2-carboxamide (Intermediate 7-6; 10.81 g, 30.60 mmol) in THF
(320 mL) and water (80 mL) and the resulting cloudy suspension was
stirred at ambient temperature for 30 minutes. 1M hydrochloric acid
(21.42 mL, 21.42 mmol) was added and the resulting suspension was
stirred at ambient temperature for 17 hours. The reaction mixture
was evaporated and diluted with water (100 mL) and the precipitate
was collected by filtration, washed with water (400 mL) and dried
under vacuum at 65.degree. C. over 4 hours to afford
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenylboronic acid (7.13 g,
86%) as a white solid, which was used without further
purification.
[0336] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.58 (3H, s), 2.74
(3H, s), 7.60 (1H, s), 7.69 (2H, d), 7.91 (2H, d), 7.98 (1H, s),
8.13 (2H, s). m/z (ES+) (M+H)+=272
Intermediate 5-2: Methyl
2-(3-(trifluoromethyl)-4-(trifluoromethylsulfonyloxy)phenyl)acetate
##STR00067##
[0338] Triethylamine (1.964 mL, 14.09 mmol) was added dropwise to a
stirred solution of methyl
2-(4-hydroxy-3-(trifluoromethyl)phenyl)acetate (Intermediate 5-3;
1.10 g, 4.70 mmol) and trifluoromethanesulphonic anhydride (1.156
mL, 7.05 mmol) in DCM (20 mL) at 0.degree. C., over a period of 3
minutes under nitrogen. The resulting solution was stirred at
0.degree. C. for 90 minutes. The reaction mixture was diluted with
DCM (100 mL), and washed sequentially with saturated NaHCO.sub.3
(75 mL) and saturated brine (75 mL). The organic layer was dried
over MgSO.sub.4, filtered and evaporated to afford crude product.
The crude product was purified by flash silica chromatography,
elution gradient 0 to 20% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford methyl
2-(3-(trifluoromethyl)-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(1.410 g, 82%) as a yellow oil which solidified on standing.
[0339] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 3.71 (2H, s),
3.74 (3H, s), 7.47 (1H, d), 7.57-7.60 (1H, m), 7.67 (1H, s). m/z
(ES-) (M-H)-=365
Intermediate 5-3: Methyl
2-(4-hydroxy-3-(trifluoromethyl)phenyl)acetate
##STR00068##
[0341] Boron tribromide (8.02 mL, 84.87 mmol) was added dropwise to
2-(4-methoxy-3-(trifluoromethyl)phenyl)acetic acid (3.31 g, 14.13
mmol) in dichloromethane (250 mL) while maintaining the temperature
below 10.degree. C. After complete addition the reaction mixture
was removed from the ice bath and allowed to stir at ambient
temperature under nitrogen for 90 minutes. The reaction mixture was
added dropwise to ice cold methanol (150 mL) and the mixture was
stirred at ambient temperature for a further 40 minutes. The
reaction mixture was evaporated to afford to afford crude product.
The crude product was purified by flash silica chromatography,
elution gradient 0 to 20% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford methyl
2-(4-hydroxy-3-(trifluoromethyl)phenyl)acetate (1.100 g, 33.2%) as
a pale yellow oil.
[0342] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 3.59 (2H, s),
3.71 (3H, s), 5.71 (1H, s), 6.88 (1H, d), 7.30-7.34 (1H, m),
7.40-7.41 (1H, m). m/z (ES-) (M-H)-=233
Example 6
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2,2'-difluorobiphenyl-4-yl)ac-
etic acid
##STR00069##
[0344] Powdered potassium hydroxide (96 mg, 1.71 mmol) was added in
one portion to methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,2'-difluorobiphenyl-4-yl)a-
cetate (Intermediate 6-1; 234 mg, 0.57 mmol) in tert-butanol (10
mL) at 45.degree. C. The resulting solution was stirred at
45.degree. C. for 30 minutes, 2M HCl (2 mL) was added and the
mixture was evaporated to remove the organic solvent. The
suspension was collected by filtration, washed with water (5 mL)
and dried under vacuum to afford crude product. The crude product
was purified by preparative HPLC (Waters XBridge Prep C18 OBD
column, 5.mu. silica, 50 mm diameter, 150 mm length), using
decreasingly polar mixtures of water (containing 0.1% formic acid)
and MeCN as eluents. Fractions containing the desired compound were
evaporated to dryness to afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,2'-difluorobiphenyl-4-yl)a-
cetic acid (132 mg, 58.5%) as a white solid.
[0345] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.66 (3H, s), 2.77
(3H, s), 3.69 (2H, s), 7.23-7.29 (2H, m), 7.46 (1H, t), 7.58 (1H,
t), 7.62 (1H, s), 7.71 (1H, d), 7.80 (1H, d), 8.10 (1H, s), 12.49
(1H, s). m/z (ES+) (M+H)+=398
Intermediate 6-1: Methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,2'-difluorobiphenyl-4-yl)a-
cetate
##STR00070##
[0347] A solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl
trifluoromethanesulfonate (Intermediate 6-4; 302 mg, 0.77 mmol) and
methyl
2-(3-fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-
acetate (Intermediate 6-2; 226 mg, 0.77 mmol) and potassium
phosphate, tri-basic (196 mg, 0.92 mmol) in DME (10 mL), methanol
(5 mL) and water (2.5 mL) was thoughroughly degassed. The mixture
was treated with PdCl.sub.2(dppf)-DCM adduct (31.4 mg, 0.04 mmol),
degassed again and the atmosphere replaced with nitrogen before
being heated to 90.degree. C. for 4 hours. The reaction mixture was
allowed to cool to room temperature and then evaporated. The crude
product was partitioned between EtOAc (75 mL), and saturated brine
(75 mL). The organic layer was dried over MgSO.sub.4, filtered and
evaporated to afford crude product. The crude product was purified
by flash silica chromatography, elution gradient 0 to 70% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,2'-difluorobiphenyl-4-yl)a-
cetate (240 mg, 76%) as a cream solid.
[0348] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.66 (3H, s), 2.77
(3H, s), 3.66 (3H, s), 3.81 (2H, s), 7.24-7.31 (2H, m), 7.48 (1H,
t), 7.58 (1H, t), 7.62 (1H, s), 7.71 (1H, d), 7.80 (1H, d), 8.10
(1H, s). m/z (ES+) (M+H)+=412
Intermediate 6-2: Methyl
2-(3-fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)acetate
##STR00071##
[0350] To a degassed solution of methyl
2-(3-fluoro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(Intermediate 6-3; 1.82 g, 5.76 mmol) in dioxane (35 mL) was added
potassium acetate (1.751 g, 17.84 mmol), bis(pinacolato)diboron
(2.192 g, 8.63 mmol), 1,1'-bis(diphenylphosphino)ferrocene (0.194
g, 0.35 mmol) and PdCl.sub.2(dppf)-CH.sub.2Cl.sub.2 adduct (0.282
g, 0.35 mmol). The suspension was degassed and then heated, under
nitrogen, to 80.degree. C. overnight. The reaction mixture was
allowed to cool, evaporated and the residue suspended in EtOAc.
This was passed through a silica pad (3'' diameter.times.1'' deep)
washing with EtOAc. The filtrate was evaporated to afford crude
product. The crude product was purified by flash silica
chromatography, elution gradient 0 to 20% EtOAc in isohexane. Pure
fractions were evaporated to dryness to afford methyl
2-(3-fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)acetate
(1.340 g, 79%) as a colourless oil.
[0351] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.35 (12H, s),
3.62 (2H, s), 3.69 (3H, s), 6.98 (1H, d), 7.05 (1H, d), 7.69 (1H,
t). m/z GCMS (EI+) M+=294
Intermediate 6-3: Methyl
2-(3-fluoro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
##STR00072##
[0353] Trifluoromethanesulphonic anhydride (2.67 mL, 16.29 mmol)
was added dropwise to a stirred solution of methyl
2-(3-fluoro-4-hydroxyphenyl)acetate (2 g, 10.86 mmol) in DCM (47.1
mL) cooled to 0.degree. C., over a period of 5 minutes under
nitrogen. Triethylamine (4.54 mL, 32.58 mmol) was added dropwise
over 5 minutes and the resulting solution stirred at rambient
temperature for 4 hours under nitrogen. The reaction mixture was
diluted with DCM (100 mL), and washed sequentially with water (100
mL), saturated NaHCO.sub.3 (100 mL), and water (100 mL). The
organic layer was dried by passing through a phase seperating
cartridge and evaporated to afford crude product. The crude product
was purified by flash silica chromatography, elution gradient 0 to
20% EtOAc in isohexane. Pure fractions were evaporated to dryness
to afford methyl
2-(3-fluoro-4-(trifluoromethylsulfonyloxy)phenyl)acetate (2.250 g,
65.5%) as a straw yellow oil.
[0354] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 3.64 (2H, s),
3.73 (3H, s), 7.11-7.14 (1H, m), 7.22-7.31 (2H, m). m/z (ES-)
(M-H)-=315.19
Intermediate 6-4:
4-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl
trifluoromethanesulfonate
##STR00073##
[0356]
6-(3-Fluoro-4-hydroxyphenyl)-3,5-dimethylpyrazine-2-carboxamide
(Intermediate 6-5; 450 mg, 1.72 mmol),
1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide
(615 mg, 1.72 mmol) and potassium carbonate (714 mg, 5.17 mmol)
were suspended in THF (15 mL) and sealed into a microwave tube. The
reaction was heated to 120.degree. C. for 8 minutes in the
microwave reactor and cooled to RT. The suspension was filtered,
the solid was washed with EtOAc (20 mL) and the filtrate was
evaporated to afford crude product. The crude product was purified
by flash silica chromatography, elution gradient 10 to 60% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl
trifluoromethanesulfonate (508 mg, 75.0%) as a white solid.
[0357] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.62 (3H, s), 2.76
(3H, s), 7.63 (1H, s), 7.77-7.85 (2H, m), 8.09 (1H, d), 8.12 (1H,
s). m/z (ES+) (M+H)+=394
Intermediate 6-5:
6-(3-Fluoro-4-hydroxyphenyl)-3,5-dimethylpyrazine-2-carboxamide
##STR00074##
[0359] A solution of 6-chloro-3,5-dimethylpyrazine-2-carboxamide
(Intermediate A) (492 mg, 2.65 mmol) and
2-fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol
(Intermediate 6-6; 630 mg, 2.65 mmol) and potassium phosphate,
tri-basic (674 mg, 3.18 mmol) in DME (10 mL), ethanol (5 mL) and
water (2.5 mL) was thoughroughly degassed. The mixture was treated
with PdCl.sub.2(dppf)-DCM adduct (108 mg, 0.13 mmol), degassed
again and the atmosphere replaced with nitrogen before being heated
to 80.degree. C. for 4 hours. The reaction mixture was allowed to
cool to room temperature and then evaporated. The crude product was
partitioned between EtOAc (75 mL), and 1N citric acid (25 mL) and
the precipitate was collected by filtration, washed with water (10
mL) and air dried to afford
6-(3-fluoro-4-hydroxyphenyl)-3,5-dimethylpyrazine-2-carboxamide
(481 mg, 69.6%) as a beige solid, which was used without further
purification.
[0360] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.66 (3H, s), 2.78
(3H, s), 7.11 (1H, t), 7.47 (1H, d), 7.65 (1H, s), 7.70 (1H, d),
8.09 (1H, s), 10.24 (1H, s). m/z (ES+) (M+H)+=262
Intermediate 6-6:
2-Fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol
##STR00075##
[0362] A solution of 4-bromo-2-fluorophenol (1.032 mL, 9.42 mmol)
in dioxane (60.2 mL) was degassed with nitrogen for a period of 10
minutes. Potassium acetate (3.70 g, 37.70 mmol),
4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(1,3,2-dioxaborolane) (3.59
g, 14.14 mmol),
(1,1'-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) (0.465
g, 0.57 mmol) and 1,1'-bis(diphenylphosphino)ferrocene (0.317 g,
0.57 mmol) were added. The resulting mixture was stirred at
85.degree. C. under nitrogen for 17 hours (overnight). The reaction
mixture was concentrated and diluted with EtOAc (100 mL), and the
mixture was acidified with 1N citric acid (75 mL) and the mixture
was filtered through celite. The aqueous phase was separated and
extracted with EtOAc (150 mL) and organic extracts were combined,
washed with saturated brine (150 mL), dried over MgSO.sub.4,
filtered and evaporated to afford crude product which was filtered
through a pad of silica, washing through with EtOAc. The filtrate
was evaporated to afford crude product. The crude product was
purified by flash silica chromatography, elution gradient 0 to 20%
EtOAc in isohexane. Pure fractions were evaporated to dryness to
afford
2-fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol
(2.020 g, 90%) as a pale brown oil which solidified on
standing.
[0363] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.33 (12H, s),
5.38 (1H, s), 6.98 (1H, t), 7.47-7.51 (2H, m). m/z (ES-)
(M-H)-=237
Example 7
1-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)cyclobu-
tanecarboxylic acid
##STR00076##
[0365] Powdered potassium hydroxide (56.9 mg, 1.01 mmol) was added
in one portion to methyl
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)cyclob-
utanecarboxylate (Intermediate 7-1; 152 mg, 0.34 mmol)/in
tert-butanol (10 mL) at 40.degree. C. under nitrogen. The resulting
suspension was stirred at 40.degree. C. for 1 hour LCMS showed the
reaction was complete. The reaction mixture was quenched with HCl
(2.027 mL, 2.03 mmol) in ethanol (10 mL) and the resulting solution
stirred for a further 20 minutes before being evaporated to
dryness. The resulting solid was washed with water (50 mL) and
dried in a dessicator to afford
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)cyclob-
utanecarboxylic acid (68.0 mg, 46.2%) as a cream solid.
[0366] .sup.1H NMR (400 MHz, CDCl.sub.3) 1.91-2.01 (1H, m),
2.11-2.20 (1H, m), 2.55-2.63 (2H, m), 2.73 (3H, s), 2.89-2.96 (2H,
m), 3.00 (3H, s), 5.84 (1H, s), 7.31-7.33 (1H, m), 7.38 (1H d,
J=8.0 Hz), 7.48 (1H d, J=1.8 Hz), 7.57-7.59 (2H, m), 7.65-7.67 (2H,
m), 7.84 (1H, s). m/z (ES+) (M+H)+=436.16
Intermediate 7-1: Methyl
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)cyclob-
utanecarboxylate
##STR00077##
[0368] A solution of 4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenyl
trifluoromethanesulfonate (Intermediate 7-4; 289 mg, 0.77 mmol) and
methyl
1-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-
cyclobutanecarboxylate (Intermediate 7-2; 270 mg, 0.77 mmol) and
potassium phosphate, tri-basic (196 mg, 0.92 mmol) in DME (10 mL),
MeOH (5 mL) and water (2.5 mL) was thoughroughly degassed. The
mixture was treated with PdCl.sub.2(dppf)-DCM adduct (31.4 mg, 0.04
mmol), degassed again and the atmosphere replaced with nitrogen
before being heated to 90.degree. C. for 4 hours. The reaction
mixture was allowed to cool, diluted with EtOAc (40 mL) and water
(20 mL). This was passed through a silica pad washing with EtOAc.
The filtrate was separated and washed with brine (20 mL) then
evaporated to afford crude product. The crude product was purified
by flash silica chromatography, elution gradient 0 to 70% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
methyl
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)cyclob-
utanecarboxylate (239 mg, 69.0%) as a colourless gum.
[0369] .sup.1H NMR (400 MHz, CDCl.sub.3) .delta. 1.90-1.98 (1H, m),
2.06-2.14 (1H, m), 2.51-2.58 (2H, m), 2.73 (3H, s), 2.85-2.91 (2H,
m), 3.00 (3H s), 3.71 (3H, s), 5.45 (1H, s), 7.27-7.29 (1H, m),
7.36 (1H d, J=8.0 Hz), 7.44 (1H d, J=1.8 Hz), 7.57-7.59 (2H, m),
7.65-7.67 (2H, m), 7.81 (1H, s). m/z (ES+) (M+H)+=450.14
Intermediate 7-2: Methyl
1-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)cyclobu-
tanecarboxylate
##STR00078##
[0371] Lithium bis(trimethylsilyl)amide (0.872 mL, 0.87 mmol) was
added dropwise to methyl
5-bromo-2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl-
)pentanoate (Intermediate 7-3; 342 mg, 0.79 mmol) in THF (10 mL)
cooled to 0.degree. C. under nitrogen the reaction and was stirred
at 0.degree. C. for 12 hours. The reaction mixture was quenched
with saturated NH4Cl (50 mL) and was diluted with EtOAc (75 mL).
The organic layer was separated and re-extracted with EtOAc (75
mL). The combined organics were washed with saturated brine (50
mL), dried (MgSO.sub.4), filtered and concentrated to afford crude
product. The crude product was purified by flash silica
chromatography, elution gradient 0 to 30% EtOAc in isohexane. Pure
fractions were evaporated to dryness to afford methyl
1-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)cyclobu-
tanecarboxylate (273 mg, 98%) as a colourless gum.
[0372] .sup.1H NMR (400 MHz, CDCl.sub.3) .delta. 1.20 (12H, s),
1.69-1.73 (1H, m), 1.85-1.91 (1H, m), 2.28-2.35 (2H, m), 2.62-2.68
(2H, m), 3.47 (3H, s), 6.98-7.00 (1H, m), 7.11 (1H d, J=11.9 Hz),
7.49 (1H d, J=7.8 Hz)
Intermediate 7-3: Methyl
5-bromo-2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl-
)pentanoate
##STR00079##
[0374] Sodium hydride (0.153 g, 3.83 mmol) was added in one portion
to methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-
acetate (Intermediate 2-7; 1.08 g, 3.48 mmol) in DMF (20 mL) cooled
to 0.degree. C. under nitrogen. The resulting solution was stirred
at 0.degree. C. for 10 minutes. 1,3-Dibromopropane (0.392 mL, 3.83
mmol) was added to the reaction and was stirred at 0.degree. C. for
5 minutes. Sodium hydride (0.153 g, 3.83 mmol) was added in one
portion to the reaction and stir at 0.degree. C. for 1 hour. The
reaction mixture was quenched with saturated NH.sub.4Cl (50 mL).
The reaction mixture was diluted with EtOAc (75 mL), and washed
sequentially with water (4.times.50 mL) and saturated brine (50
mL). dried over MgSO.sub.4 The organic layer was evaporated to
afford crude product. The crude product was purified by flash
silica chromatography, elution gradient 0 to 30% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
methyl
5-bromo-2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl-
)phenyl)pentanoate (0.362 g, 24.12%) as a colourless gum.
[0375] .sup.1H NMR (400 MHz, CDCl.sub.3) 1.36 (12H, s), 1.71-1.86
(2H, m), 1.87-2.00 (1H, m), 2.14-2.23 (1H, m), 3.36 (2H t, J=6.7
Hz), 3.52 (1H t, J=7.7 Hz), 3.64 (3H, s), 7.13-7.17 (1H, m), 7.29
(1H q, J=1.7 Hz), 7.65 (1H d, J=7.7 Hz)
Intermediate 7-4: 4-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)phenyl
trifluoromethanesulfonate
##STR00080##
[0377] 6-(4-Hydroxyphenyl)-3,5-dimethylpyrazine-2-carboxamide
(Intermediate 7-5; 22 g, 90.44 mmol),
1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide
(32.3 g, 90.44 mmol) and potassium carbonate (37.5 g, 271.31 mmol)
were suspended in THF (611 mL) and stirred for 16 hours. The
suspension was filtered, the solid was washed with EtOAc (250 mL)
and the filtrate was evaporated to afford crude product. The crude
product was purified by flash silica chromatography, elution
gradient 0 to 80% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenyl
trifluoromethanesulfonate (34.5 g, 102%) as a cream solid.
[0378] .sup.1H NMR (400 MHz, DMSO-d6) 2.59 (3H, s), 2.75 (3H, s),
7.62-7.64 (3H, m), 7.93-7.97 (2H, m), 8.05 (1H, s). m/z (ES+)
(M+H)+=376.03
Intermediate 7-5:
6-(4-Hydroxyphenyl)-3,5-dimethylpyrazine-2-carboxamide
##STR00081##
[0380] A solution of 6-chloro-3,5-dimethylpyrazine-2-carboxamide
(Intermediate A) (20.17 g, 108.67 mmol),
4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol (26.3 g,
119.53 mmol) and tripotassium phosphate (34.6 g, 163.00 mmol) in
DME (500 mL), MeOH (250 mL) and water (125 mL) was degassed before
addition of
(1,1'-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) (DCM
adduct) (4.47 g, 5.43 mmol). The reaction mixture was heated to
80.degree. C., under nitrogen, and left to stir for 1 hour. The
reaction mixture was allowed to cool to room temperature and then
evaporated. The residue was partitioned between water (1 L), 2M HCl
aq. (1 L) and EtOAc (1 L). The aqueous was re-extracted with EtOAc
(2 L) and the combined organics washed with brine (1 L), dried
(MgSO.sub.4) and evaporated to give crude product. The aqueous was
filtered and the solid was washed with water (2 L) to give pure
product. The crude product from the organic layer was purified by
flash silica chromatography, elution gradient 20 to 80% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
6-(4-hydroxyphenyl)-3,5-dimethylpyrazine-2-carboxamide (22.00 g,
83%) as a cream solid.
[0381] .sup.1H NMR (400 MHz, DMSO-d6) 2.58 (3H, s), 2.71 (3H, s),
6.85-6.89 (2H, m), 7.56-7.60 (3H, m), 7.95 (1H, s), 9.72 (1H, s).
m/z (ES+) (M+H)+=244.19
Intermediate 7-6:
3,5-Dimethyl-6-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pyr-
azine-2-carboxamide
##STR00082##
[0383] [1,1'-Bis(diphenylphosphino)ferrocene]dichloropalladium(ii),
complex with dichloromethane (1:1) (2.59 g, 3.20 mmol) was added to
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenyl
trifluoromethanesulfonate (Intermediate 7-4; 20 g, 53.29 mmol),
4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(1,3,2-dioxaborolane) (14.88
g, 58.62 mmol), potassium acetate (15.69 g, 159.86 mmol) and
1,1'-bis(diphenylphosphino)ferrocene (1.747 g, 3.20 mmol) in
dioxane (239 mL) at RT over a period of 5 minutes under nitrogen.
The resulting suspension was degassed and refilled with nitrogen
then stirred at 80.degree. C. for 17 hours. The reaction mixture
was cooled to RT, diluted with EtOAc and Water, The organic layer
was collected, washed with brine and evaporated to a brown oil
which solidified on standing. The crude product was purified by
flash silica chromatography, elution gradient 20 to 80% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
3,5-dimethyl-6-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pyr-
azine-2-carboxamide (17.20 g, 91%) as a cream solid.
[0384] .sup.1H NMR (400 MHz, CDCl.sub.3) 1.38 (12H, s), 2.65 (3H,
s), 2.99 (3H, s), 5.45 (1H, s), 7.56-7.59 (2H, m), 7.78 (1H, s),
7.93-7.95 (2H, m). m/z (ES+) (M+H)+=354.22
Example 8
(S)-2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)pro-
panoic acid and
Example 9
(R)-2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)pro-
panoic acid
##STR00083##
[0386] Powdered potassium hydroxide (331 mg, 5.90 mmol) was added
in one portion to methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)propan-
oate (Intermediate 8-1; 834 mg, 1.97 mmol) in tert-butanol (20 mL)
at 45.degree. C. The resulting solution was stirred at 45.degree.
C. for 30 minutes. 2M HCl (6 mL) was added and the mixture was
evaporated to remove the organic solvent. The suspension was
collected by filtration, washed with water and dried under vacuum
to afford crude product. The crude product was purified by flash
silica chromatography, elution gradient 0 to 10% MeOH in DCM.
Fractions containing the desired compound were evaporated to
dryness to afford racemic
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)propan-
oic acid (603 mg, 74.8%) as a white solid. This was purified by
preparative chiral-HPLC on a OJ column, eluting isocratically with
30% EtOH in isohexane (acidified with AcOH) as eluent. The
fractions containing the desired compound were evaporated to
dryness to afford: [0387]
(R)-2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl--
4-yl)propanoic acid (first eluted, 0.531 g, 40.8%) as a white
solid
[0388] .sup.1H NMR (400 MHz, CDCl.sub.3) .delta. 1.59 (3H, d, J=7.2
Hz), 2.73 (3H, s), 3.00 (3H, s), 3.81 (1H q, J=7.2 Hz), 5.84 (1H,
s), 7.32-7.39 (2H, m), 7.50 (1H, s), 7.57 (2H d, J=8.3 Hz), 7.66
(2H d, J=8.3 Hz), 7.84 (1H, s). LCMS: m/z (ES+) (M+H)+=410 [0389]
and
(S)-2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)pr-
opanoic acid (second eluted, 0.537 g, 41.3%).
[0390] .sup.1H NMR (400 MHz, CDCl.sub.3) .delta. 1.60 (3H, d,),
2.73 (3H, s), 3.00 (3H, s), 3.78-3.82 (1H, m), 5.80 (1H, s),
7.32-7.39 (2H, m), 7.50 (1H, s), 7.57 (2H d, J=8.3 Hz), 7.66 (2H d,
J=8.3 Hz), 7.83 (1H, s). LCMS: m/z (ES+) (M+H)+=410
[0391] The R-enantiomer (150 mg, 0.37 mmol) was purified by
crystallisation from EtOH to afford
(R)-2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)pr-
opanoic acid (56.0 mg, 37.3%) as a pale yellow crystalline solid.
m/z (ES+) (M+H)+=410.
[0392] The absolute configuration of the R-enantiomer was deduced
by single crystal X-ray crystallography based on the anomalous
scattering contribution to the measured diffraction
intensities.
Intermediate 8-1: Methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)propan-
oate
##STR00084##
[0394] A solution of 4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenyl
trifluoromethanesulfonate (Intermediate 7-4; 1.249 g, 3.33 mmol)
and methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-
propanoate (Intermediate 8-2; 1.08 g, 3.33 mmol) and potassium
phosphate, tri-basic (0.847 g, 3.99 mmol) in DME (16 mL), methanol
(8.00 mL) and water (4.00 mL) was thoughroughly degassed. The
mixture was treated with PdCl.sub.2(dppf)-DCM adduct (0.136 g, 0.17
mmol), degassed again and the atmosphere replaced with nitrogen
before being heated to 90.degree. C. for 4 hours in the microwave.
The reaction mixture was allowed to cool to room temperature and
then evaporated. The crude product was partitioned between EtOAc
(75 mL), and saturated brine (75 mL). The organic layer was dried
over MgSO.sub.4, filtered and evaporated to afford crude product.
The crude product was purified by flash silica chromatography,
elution gradient 0 to 70% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)propan-
oate (0.841 g, 59.6%) as a beige solid.
[0395] .sup.1H NMR (400 MHz, CDCl.sub.3) 1.56 (3H d, J=7.2 Hz),
2.73 (3H, s), 3.00 (3H, s), 3.72 (3H, s), 3.77 (1H q, J=7.2 Hz),
5.47 (1H, s), 7.28-7.31 (1H, m), 7.46 (1H d, J=1.8 Hz), 7.35-7.81
(2H, m), 7.56-7.59 (2H, m), 7.65-7.68 (2H, m). m/z (ES+)
(M+H)+=424
Intermediate 8-2: methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)propano-
ate
##STR00085##
[0397] Lithium bis(trimethylsilyl)amide (7.79 mL, 7.79 mmol) was
added to methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-
acetate (Intermediate 2-7; 2.2 g, 7.08 mmol) in THF (50 mL) cooled
to 0.degree. C. under nitrogen. The resulting solution was stirred
at 0.degree. C. for 30 minutes. Next methyl iodide (0.530 mL, 8.50
mmol) was added and the reaction stirred for 30 minutes Ammonium
chloride (satd) (50 mL) was added with vigorous stirring, ethyl
acetate (100 mL) and water (50 mL) were added and the organic phase
separated, washed with water (50 mL) and saturated brine (50 mL).
The organic layer was dried over MgSO.sub.4, filtered and
evaporated to afford crude product. The crude product was purified
by flash silica chromatography, elution gradient 0 to 40% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)propano-
ate (1.290 g, 56.1%) as a colourless oil.
[0398] .sup.1H NMR (400 MHz, CDCl.sub.3) 1.36 (12H, s), 1.48 (3H d,
J=7.2 Hz), 3.65 (3H, s), 3.65-3.69 (1H, m), 7.15-7.17 (1H, m), 7.29
(1H d, J=1.7 Hz), 7.65 (1H d, J=7.7 Hz)
Example 10
1-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)cyclopr-
opanecarboxylic acid
##STR00086##
[0400] Powdered potassium hydroxide (52.1 mg, 0.93 mmol) was added
in one portion to methyl
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)cyclop-
ropanecarboxylate (Intermediate 10-1; 135 mg, 0.31 mmol) in
tert-butanol (5 mL) at 45.degree. C. The resulting solution was
stirred at 45.degree. C. for 30 minutes. 2N HCl (1 mL) was added
and the mixture was evaporated to remove the organic solvent. The
suspension was collected by filtration, washed with water and dried
under vacuum to afford crude product. The crude product was
purified by preparative HPLC (Waters XBridge Prep C18 OBD column,
5.mu. silica, 50 mm diameter, 150 mm length), using decreasingly
polar mixtures of water (containing 0.1% TFA) and MeCN as eluents.
Fractions containing the desired compound were evaporated to
dryness to afford
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)cyclop-
ropanecarboxylic acid (30.0 mg, 22.96%) as a white solid.
[0401] .sup.1H NMR (400 MHz, DMSO-d6) 1.23-1.25 (2H, m), 1.48-1.51
(2H, m), 2.65 (3H, s), 2.76 (3H, s), 7.41 (2H t, J=7.6 Hz),
7.53-7.58 (3H, m), 7.61 (1H, s), 7.84-7.86 (2H, m), 8.04 (1H, s),
12.47 (1H, s). m/z (ES+) (M+H)+=422
Intermediate 10-1: Methyl
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)cyclop-
ropanecarboxylate
##STR00087##
[0403] A solution of 4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenyl
trifluoromethanesulfonate (Intermediate 7-4; 245 mg, 0.65 mmol) and
methyl
1-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-
cyclopropanecarboxylate (Intermediate 10-2; 220 mg, 0.65 mmol) and
potassium phosphate, tri-basic (166 mg, 0.78 mmol) in DME (4 mL),
methanol (2 mL) and water (1 mL) was thoughroughly degassed. The
mixture was treated with PdCl.sub.2(dppf)-DCM adduct (26.7 mg, 0.03
mmol), degassed again and the atmosphere replaced with nitrogen
before being heated to 90.degree. C. for 4 hours in the microwave.
The reaction mixture was allowed to cool to room temperature and
then evaporated. The crude product was partitioned between EtOAc
(75 mL), and saturated brine (75 mL). The organic layer was dried
over MgSO.sub.4, filtered and evaporated to afford crude product.
The crude product was purified by flash silica chromatography,
elution gradient 0 to 70% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford methyl
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)cyclop-
ropanecarboxylate (141 mg, 49.5%) as a colourless gum.
[0404] .sup.1H NMR (400 MHz, CDCl.sub.3) 1.24-1.27 (2H, m),
1.66-1.69 (2H, m), 2.73 (3H, s), 3.00 (3H, s), 3.69 (3H, s), 5.52
(1H, s), 7.34-7.68 (7H, m), 7.82 (1H, s). m/z (ES+) (M+H)+=436
Intermediate 10-2: Methyl
1-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)cyclopr-
opanecarboxylate
##STR00088##
[0406] Lithium bis(trimethylsilyl)amide (7.08 mL, 7.08 mmol) was
added dropwise to methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)acetate
(1 g, 3.22 mmol) in THF (20 mL) cooled to 0.degree. C. under
nitrogen. The resulting solution was stirred at 0.degree. C. for 30
minutes and then 1,2-dibromoethane (0.305 mL, 3.54 mmol) was added
to the reaction and was stirred at 0.degree. C. for 5 minutes. The
reaction mixture was quenched with saturated NH.sub.4Cl (50 mL) and
was diluted with EtOAc (75 mL). The organic layer was separated and
re-extracted with EtOAc (75 mL). The combined organics were washed
with saturated brine (50 mL), dried (MgSO.sub.4), filtered and
concentrated to afford crude product. The crude product was
purified by flash silica chromatography, elution gradient 0 to 30%
EtOAc in isohexane. Pure fractions were evaporated to dryness to
afford methyl
1-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)cyclopr-
opanecarboxylate (0.182 g, 16.79%) as a colourless gum.
[0407] .sup.1H NMR (400 MHz, CDCl.sub.3) .delta. 1.15-1.18 (2H, m),
1.36 (12H, s), 1.58-1.61 (2H, m), 3.61-3.61 (3H, m), 7.19-7.22 (1H,
m), 7.33 (1H d, J=1.6 Hz), 7.64 (1H d, J=7.7 Hz)
Example 11
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)butanoi-
c acid
##STR00089##
[0409] A solution of 4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenyl
trifluoromethanesulfonate (Intermediate 11-1; 760 mg, 2.03 mmol)
and methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-
butanoate (686 mg, 2.03 mmol) and potassium phosphate, tri-basic
(516 mg, 2.43 mmol) in DME (10 mL), ethanol (5 mL) and water (2.5
mL) was thoughroughly degassed. The mixture was treated with
PdCl.sub.2(dppf)-DCM adduct (83 mg, 0.10 mmol), degassed again and
the atmosphere replaced with nitrogen before being heated to
90.degree. C. for 4 hours. The reaction mixture was allowed to
cool, diluted with EtOAc (40 mL) and water (20 mL). This was passed
through a silica pad washing with EtOAc. The filtrate was separated
and washed with brine (20 mL) then evaporated to afford crude
product. The crude product was purified by flash silica
chromatography, elution gradient 0 to 70% EtOAc in isohexane. Pure
fractions were evaporated to dryness to afford a colourless gum,
powdered potassium hydroxide (597 mg, 10.63 mmol) was added in one
portion to this in tert-butanol (25 mL) at 45.degree. C. under
nitrogen. The resulting solution was stirred at 45.degree. C. for 1
hour. The mixture was treated with acetic acid (0.812 mL, 14.18
mmol) in ethanol (20 mL) and stirred at room temperature for 10
minutes. The mixture was then evaporated under vacuum to give an
off white solid. This was triturated with water (20 mL), filtered
off and washed with water (10 mL), before drying under vacuum to
give crude solid. The crude product was purified by flash silica
chromatography, elution gradient 0 to 10% MeOH in DCM. Fractions
containing the desired compound were evaporated to dryness to
afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)butano-
ic acid (42.0 mg, 5.59%) as a white foam.
[0410] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 0.93 (3H, t),
1.82 (1H, dt), 2.12 (1H, dt), 2.66 (3H, s), 2.92 (3H, s), 3.48 (1H,
t), 6.22 (1H, d), 7.28 (2H, dd), 7.44 (1H, d), 7.51 (2H, dt), 7.58
(2H, dt), 7.79 (1H, d). m/z (ES+) (M+H)+=424.38
Intermediate 11-1: Methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)butanoa-
te
##STR00090##
[0412] Lithium bis(trimethylsilyl)amide (3.86 mL, 3.86 mmol) was
added to methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-
acetate (Intermediate 2-7; 1 g, 3.22 mmol) in THF (10 mL) cooled to
0.degree. C. under nitrogen. The resulting solution was stirred at
0.degree. C. for 30 minutes. Iodoethane, stabilized with silver
(0.258 mL, 3.22 mmol), was added and the reaction stirred for 30
minutes Ammonium chloride (satd) (25 mL) added with vigorous
stirring, ethyl acetate (50 mL) added and the organic phase
separated, washed with water (25 mL) and saturated brine (25 mL).
The organic layer was dried over MgSO.sub.4, filtered and
evaporated to afford crude product. The crude product was purified
by flash silica chromatography, elution gradient 0 to 10% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)butanoa-
te (0.686 g, 62.9%) as a colourless oil.
[0413] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 0.80 (2H, t),
1.29 (12H, s), 1.86-2.06 (2H, m), 3.34 (1H, t), 3.57 (3H, s), 7.04
(1H, d), 7.19 (2H, d), 7.58 (1H, d). m/z (EI+) (M+H)+=338
Example 12
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-methylbiphenyl-4-yl)acetic
acid
##STR00091##
[0415] Powdered potassium hydroxide (65.9 mg, 1.17 mmol) was added
in one portion to ethyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-methylbiphenyl-4-yl)acetat-
e (Intermediate 12-1; 79 mg, 0.20 mmol) in tert-butanol (2 mL) at
45.degree. C. under nitrogen. The resulting solution was stirred at
45.degree. C. for 1 hour. The mixture was treated with acetic acid
(0.090 mL, 1.57 mmol) in ethanol (1 mL) and stirred at room
temperature for 10 minutes. The mixture was then evaporated under
vacuum to give an off white solid. This was triturated with water
(10 mL), filtered off and washed with water (10 mL), before drying
under vacuum to give desired product.
[0416] .sup.1H NMR (400.13 MHz, DMSO-d6) .delta. 2.28 (3H, s), 2.65
(3H, s), 2.76 (3H, s), 3.58 (2H, s), 7.19 (3H, dd), 7.47 (2H, dd),
7.61 (1H, s), 7.82 (2H, dt), 8.03 (1H, s), 12.30 (1H, s). m/z (ES+)
(M+H)+=376.37
Intermediate 12-1: Ethyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-methylbiphenyl-4-yl)acetat-
e
##STR00092##
[0418] A solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenylboronic acid (138 mg,
0.51 mmol), methyl
2-(3-methyl-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(Intermediate 12-2; 159 mg, 0.51 mmol) and tripotassium phosphate
(162 mg, 0.76 mmol) in DME (3 mL), ethanol (1.5 mL) and water (0.5
mL) was degassed before addition of
(1,1'-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) (DCM
adduct) (33.5 mg, 0.04 mmol). The reaction mixture was heated to
80.degree. C., under nitrogen, and left to stir overnight for 16
hrs. The reaction mixture was allowed to cool to room temperature
and then evaporated. The residue was partitioned between water (20
mL) and EtOAc (50 mL). The aqueous was re-extracted with EtOAc
(2.times.10 mL) and the combined organics washed with brine (20
mL), dried (MgSO.sub.4) and evaporated to give crude product. The
crude product was purified by flash silica chromatography, elution
gradient 10 to 100% EtOAc in isohexane on 12 g silicycle column.
Pure fractions were evaporated to dryness to afford ethyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-methylbiphenyl-4-yl)acetat-
e (79 mg, 38.4%) as a colourless oil which crystallised on
standing.
[0419] .sup.1H NMR (400.132 MHz, DMSO) .delta. 1.17 (3H, t), 2.28
(3H, s), 2.65 (3H, s), 2.76 (3H, s), 3.67 (2H, s), 4.08-4.13 (2H,
m), 7.17-7.24 (3H, m), 7.47 (2H, d), 7.61 (1H, s), 7.82 (2H, d),
8.02 (1H, s). m/z (ES+) (M+H)+=404
Intermediate 12-2: Methyl
2-(3-methyl-4-(trifluoromethylsulfonyloxy)phenyl)acetate
##STR00093##
[0421] Trifluoromethane sulfonic anhydride (0.217 mL, 1.32 mmol)
was added dropwise to methyl 2-(4-hydroxy-3-methylphenyl)acetate
(159 mg, 0.88 mmol), in DCM (4 mL) at 0.degree. C. under nitrogen.
The resulting solution was then treated with triethylamine (0.369
mL, 2.65 mmol) and allowed to warm to and stir at 18.degree. C. for
16 hours. The mixture was diluted with DCM (20 mL) and water (20
mL) and the organics separated. The organics were washed with
saturated NaHCO.sub.3 (aq, 50 mL), brine (10 mL) dried (MgSO.sub.4)
and evaporated to crude material. The crude product was purified by
flash silica chromatography, elution gradient 0 to 30% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
methyl 2-(3-methyl-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(169 mg, 61.3%) as a colourless oil.
[0422] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.30 (3H, s), 3.62
(3H, s), 3.72 (2H, s), 7.26-7.29 (1H, m), 7.33 (1H, d), 7.35-7.36
(1H, m). m/z (ES-) (M-H)-=311
Example 13
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)-2-meth-
ylpropanoic acid
##STR00094##
[0424] Lithium bis(trimethylsilyl)amide (9.66 mL, 9.66 mmol) was
added to methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-
acetate (Intermediate 2-7; 2.5 g, 8.05 mmol) in THF (25 mL) cooled
to 0.degree. C. under nitrogen. The resulting solution was stirred
at 0.degree. C. for 30 minutes. Methyl iodide (0.752 mL, 12.07
mmol) was added and the reaction stirred for 30 minutes Ammonium
chloride (satd) (25 mL) added with vigorous stirring, ethyl acetate
(50 mL) added and the organic phase separated, washed with water
(25 mL) and saturated brine (25 mL). The organic layer was dried
over MgSO.sub.4, filtered and evaporated to afford crude product
(5.67 g). The crude product was purified by flash silica
chromatography, elution gradient 0 to 10% EtOAc in isohexane. Pure
fractions were evaporated to dryness to afford a colourless oil. To
this was added a solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenyl
trifluoromethanesulfonate (Intermediate 7-4; 809 mg, 2.16 mmol) and
potassium phosphate, tri-basic (549 mg, 2.59 mmol) in DME (10 mL),
methanol (5.00 mL) and water (2.500 mL) was thoughroughly degassed.
The mixture was treated with PdCl.sub.2(dppf)-DCM adduct (88 mg,
0.11 mmol), degassed again and the atmosphere replaced with
nitrogen before being heated to 90.degree. C. for 4 hours. The
reaction mixture was allowed to cool, diluted with EtOAc (40 mL)
and water (20 mL). This was passed through a silica pad washing
with EtOAc. The filtrate was separated and washed with brine (20
mL) then evaporated to afford crude product. The crude product was
purified by flash silica chromatography, elution gradient 0 to 70%
EtOAc in isohexane. Pure fractions were evaporated to dryness to
afford a cream solid, powdered potassium hydroxide (476 mg, 8.49
mmol) was added in one portion to this in tert-butanol (25 mL) at
45.degree. C. under nitrogen. The resulting solution was stirred at
100.degree. C. for 16 hours. The mixture was treated with acetic
acid (0.648 mL, 11.32 mmol) in ethanol (20 mL) and stirred at room
temperature for 10 minutes. The mixture was then evaporated under
vacuum to give an off white solid. This was triturated with water
(20 mL), filtered off and washed with water (10 mL), before drying
under vacuum to give crude solid. The crude product was purified by
preparative HPLC (Waters XBridge Prep C18 OBD column, 5.mu. silica,
50 mm diameter, 150 mm length), using decreasingly polar mixtures
of water (containing 0.1% formic acid) and MeCN as eluents.
Fractions containing the desired compound were evaporated to
dryness to afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl-
)-2-methylpropanoic acid (53.0 mg, 8.83%) as a white foam.
[0425] .sup.1H NMR (400.13 MHz, DMSO-d6) .delta. 1.53 (6H, s), 2.65
(3H, s), 2.76 (3H, s), 7.43 (2H, dd), 7.50 (1H, d), 7.58 (2H, dt),
7.61 (1H, s), 7.85 (2H, dt), 8.04 (1H, s), 12.57 (1H, s). m/z (ES+)
(M+H)+=424.37
Example 14
2-(2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acet-
amido)-2-methylpropanoic acid
##STR00095##
[0427] Potassium hydroxide (109 mg, 1.94 mmol) was added in one
portion to methyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-
-yl)acetamido)-2-methylpropanoate (Intermediate 14-1; 319.5 mg,
0.65 mmol) in t-BuOH (4164 .mu.L) at room temperature. The
resulting solution was stirred at 45.degree. C. for 5 hours and a
precipitate formed. The reaction mixture was quenched with 2M HCl
(5 mL), The reaction mixture was evaporated to dryness and
redissolved in water (10 mL), and filtered through nylon, washed
with water and dried under vacuum. The crude product was purified
by preparative HPLC (Waters XBridge Prep C18 OBD column, 5.mu.
silica, 50 mm diameter, 150 mm length), using decreasingly polar
mixtures of water (containing 0.1% formic acid) and MeCN as
eluents. Fractions containing the desired compound were evaporated
to dryness to afford
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)-2-methylpropanoic acid (18.20 mg, 5.86%) as a white
solid.
[0428] .sup.1H NMR (400.132 MHz, MeOD) .delta. 1.50 (6H, s),2.69
(3H, s),2.87 (3H, s),3.57 (2H, s),7.37 (2H, d), 7.49 (1H, s),7.57
(2H, d), 7.75 (2H, d). m/z (ES+), (M+H)+=481
Intermediate 14-1: Methyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)-2-methylpropanoate
##STR00096##
[0430] A mixture of methyl 2-amino-2-methylpropanoate hydrochloride
(88 mg, 0.57 mmol) and N-ethyl-N-isopropylpropan-2-amine (99 .mu.L,
0.57 mmol) in DMF (342 .mu.L) were treated with a solution of
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetic
acid (Example 1; 205 mg, 0.52 mmol),
1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (124
mg, 0.65 mmol), 1H-benzo[d][1,2,3]triazol-1-ol (70.0 mg, 0.52 mmol)
and N-ethyl-N-isopropylpropan-2-amine (99 .mu.L, 0.57 mmol) in DMF
(2049 .mu.L) at RT. The resulting solution was stirred at RT for 20
hours. The reaction mixture was evaporated to dryness and
redissolved in DCM (5 mL), and washed with water (5 mL). The
organic layer was evaporated to afford methyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-
-yl)acetamido)-2-methylpropanoate (320 mg, 125%) which was used
without further purification.
[0431] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 1.25-1.27 (3H,
m), 1.51 (4H, s), 2.59 (1H, s), 2.66 (3H, s), 2.81 (14H, s),
2.89-2.93 (16H, m), 2.92 (1H, s), 3.50 (1H, s), 3.69 (2H, s), 5.23
(21H, s), 7.19 (4H, s), 7.30 (1H, s), 7.51 (2H, d), 7.59 (2H, d),
7.95 (5H, s) m/z (ES+), (M+H)+=495
Example 15
(S)-2-(2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)-
acetamido)-4-methylpentanoic acid
##STR00097##
[0433] Potassium hydroxide (70.3 mg, 1.25 mmol) was added in one
portion to (S)-ethyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)-4-methylpentanoate (Intermediate 15-1; 224.4 mg, 0.42 mmol)
in t-BuOH (2696 .mu.L) at RT. The resulting solution was stirred at
45.degree. C. for 5 hours a precipitate formed. The reaction
mixture was quenched with 2M HCl (5 mL), The reaction mixture was
evaporated to dryness and redissolved in water (10 mL), and
filtered through nylon, washed with water and dried under vacuum.
The crude product was purified by preparative HPLC (Waters XBridge
Prep C18 OBD column, 5.mu. silica, 50 mm diameter, 150 mm length),
using decreasingly polar mixtures of water (containing 0.1% formic
acid) and MeCN as eluents. Fractions containing the desired
compound were evaporated to dryness to afford
(S)-2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl-
)acetamido)-4-methylpentanoic acid (20.40 mg, 9.59%) as a white
solid.
[0434] .sup.1H NMR (400.132 MHz, MeOD) d0.92 (3H, d), 0.97 (3H, d),
1.44 (1H, s),1.60-1.77 (3H, m), 2.69 (3H, s),2.87 (3H, s),3.63 (2H,
s),4.43-4.50 (1H, m),7.33-7.40 (2H, m),7.52 (2H, s), 7.56 (1H,
s),7.57 (2H, d), 7.76 (2H, d). m/z (ES+), (M+H)+=509
Intermediate 15-1: (S)-Ethyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)-4-methylpentanoate
##STR00098##
[0436] A mixture of (S)-ethyl 2-amino-4-methylpentanoate
hydrochloride (111 mg, 0.57 mmol) and
N-ethyl-N-isopropylpropan-2-amine (99 .mu.L, 0.57 mmol) in DMF (342
.mu.L) were treated with a solution of
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetic
acid (Example 1; 205 mg, 0.52 mmol),
1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (124
mg, 0.65 mmol), 1H-benzo[d][1,2,3]triazol-1-ol (70.0 mg, 0.52 mmol)
and N-ethyl-N-isopropylpropan-2-amine (99 .mu.L, 0.57 mmol) in DMF
(2049 .mu.L) at RT. The resulting solution was stirred at RT for 20
hours. The reaction was incomplete so the temperature was increased
to 50.degree. C. and the reaction mixture was stirred for a further
3 hours. The reaction mixture was diluted with EtOAc (20 mL), and
washed sequentially with water (50 mL), saturated brine (50 mL),
and water (100 mL). The organic layer was dried over MgSO.sub.4,
filtered and evaporated to afford (S)-ethyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobipheny-
l-4-yl)acetamido)-4-methylpentanoate (224 mg, 81%) which was used
without further purification. m/z (ES+), (M+H)+=537
Example 16
3-(2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acet-
amido)propanoic acid
##STR00099##
[0438] Potassium hydroxide (131 mg, 2.34 mmol) was added in one
portion to ethyl
3-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4--
yl)acetamido)propanoate (Intermediate 16-1; 386.5 mg, 0.78 mmol) in
t-BuOH (5038 .mu.L) at RT. The resulting solution was stirred at
45.degree. C. for 5 hours a precipitate formed. The reaction
mixture was quenched with 2M HCl (5 mL), The reaction mixture was
evaporated to dryness and redissolved in water (10 mL), and
filtered through nylon, washed with water and dried under vacuum.
The crude product was purified by preparative HPLC (Waters XBridge
Prep C18 OBD column, 5.mu. silica, 50 mm diameter, 150 mm length),
using decreasingly polar mixtures of water (containing 0.1% formic
acid) and MeCN as eluents. Fractions containing the desired
compound were evaporated to dryness to afford
3-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)propanoic acid (56.4 mg, 15.47%) as a white solid.
[0439] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.47 (2H, t), 2.71
(3H, s), 2.83 (3H, s), 3.35 (2H, s), 3.55 (2H, s), 7.38 (1H, d),
7.48 (1H, d), 7.54 (1H, d), 7.63 (2H, d), 7.68 (1H, s), 7.91 (2H,
d), 8.11 (1H, s), 8.26 (1H, t), 1 2.27 (1H, s). m/z (ES+),
(M+H)+=467
Intermediate 16-1: Ethyl
3-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)propanoate
##STR00100##
[0441] A mixture of ethyl 3-aminopropanoate hydrochloride (88 mg,
0.57 mmol) and N-ethyl-N-isopropylpropan-2-amine (99 .mu.L, 0.57
mmol) in DMF (342 .mu.L) were treated with a solution of
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetic
acid (Example 1; 205 mg, 0.52 mmol),
1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (124
mg, 0.65 mmol), 1H-benzo[d][1,2,3]triazol-1-ol (70.0 mg, 0.52 mmol)
and N-ethyl-N-isopropylpropan-2-amine (99 .mu.L, 0.57 mmol) in DMF
(2049 .mu.L) at RT. The resulting solution was stirred at RT for 20
hours. The reaction mixture was evaporated to dryness and
redissolved in DCM (5 mL), and washed with water (5 mL). The
organic layer was evaporated to afford ethyl
3-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4--
yl)acetamido)propanoate (387 mg, 151%) which was used without
further purification.
[0442] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 1.18 (3H, t),
1.28 (3H, d), 2.48 (2H, t), 2.66 (3H, s), 2.81 (7H, s), 2.89-2.93
(10H, m), 3.48 (3H, t), 4.07 (2H, t), 5.23 (5H, s), 7.19 (4H, s),
7.20 (1H, s), 7.29-7.31 (1H, m), 7.35 (1H, d), 7.49-7.51 (2H, m),
7.58-7.61 (2H, m), 7.95 (2H, s). m/z (ES+), (M+H)+=495
Example 17
(S)-2-(2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)-
acetamido)-3-methylbutanoic acid
##STR00101##
[0444] Potassium hydroxide (108 mg, 1.93 mmol) was added in one
portion to (S)-methyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)-3-methylbutanoate (Intermediate 17-1; 327.4 mg, 0.64 mmol)
in t-BuOH (4150 .mu.L) at RT. The resulting solution was stirred at
45.degree. C. for 5 hours a precipitate formed. The reaction
mixture was quenched with 2M HCl (5 mL), The reaction mixture was
evaporated to dryness and redissolved in water (10 mL), and
filtered through nylon, washed with water and dried under vacuum.
The crude product was purified by preparative HPLC (Waters XBridge
Prep C18 OBD column, 5.mu. silica, 50 mm diameter, 150 mm length),
using decreasingly polar mixtures of water (containing 0.1% formic
acid) and MeCN as eluents. Fractions containing the desired
compound were evaporated to dryness to afford
(S)-2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl-
)acetamido)-3-methylbutanoic acid (93 mg, 29.1%) as a white
solid.
[0445] .sup.1H NMR (400.132 MHz, MeOD) .delta. 0.98 (3H, d), 0.99
(3H, d), 2.15-2.26 (1H, m),2.69 (3H, s), 2.88 (3H, s),3.67 (2H,
s),4.33-4.39 (1H, m),7.52 (1H, s),7.57 (2H, d), 7.63 (1H, d), 7.76
(2H, d), 7.80 (1H, d). m/z (ES+), (M+H)+=495
Intermediate 17-1: (S)-Methyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)-3-methylbutanoate
##STR00102##
[0447] A mixture of (S)-methyl 2-amino-3-methylbutanoate
hydrochloride (95 mg, 0.57 mmol) and
N-ethyl-N-isopropylpropan-2-amine (99 .mu.L, 0.57 mmol) in DMF (342
.mu.L) were treated with a solution of
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetic
acid (Example 1; 205 mg, 0.52 mmol),
1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (124
mg, 0.65 mmol), 1H-benzo[d][1,2,3]triazol-1-ol (70.0 mg, 0.52 mmol)
and N-ethyl-N-isopropylpropan-2-amine (99 .mu.L, 0.57 mmol) in DMF
(2049 .mu.L) at RT. The resulting solution was stirred at RT for 20
hours. The reaction mixture was evaporated to dryness and
redissolved in DCM (5 mL), and washed with water (5 mL). The
organic layer was evaporated to afford (S)-methyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)-3-methylbutanoate (327 mg, 124%) which was used without
further purification.
[0448] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. -0.07 (2H, s),
0.81 (3H, d), 0.86-0.87 (3H, m), 1.26 (2H, d), 2.59 (1H, s), 2.66
(3H, s), 2.81 (9H, s), 2.88-2.93 (12H, m), 3.57 (2H, s), 3.68 (3H,
s), 4.51-4.54 (1H, m), 5.23 (10H, s), 7.19-7.24 (4H, m), 7.32 (2H,
d), 7.39 (1H, d), 7.50-7.52 (2H, m), 7.58-7.60 (2H, m), 7.95 (3H,
s). m/z (ES+), (M+H)+=509
Example 18
2-(2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)-N-m-
ethylacetamido)-2-methylpropanoic acid
##STR00103##
[0450] A solution of benzyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-1;
chlorobiphenyl-4-yl)-N-methylacetamido)-2-methylpropanoate
(Intermediate 18-1 2.46 g, 0.78 mmol) in EtOAc (13.3 mL) and MeOH
(2.2 mL) were hydrogenated in the H-Cube hydrogenation cell using a
55 mm 10% palladium on carbon cartridge, at RT and 50 bar at a flow
rate of 1 mL/minute. The resulting solution was evaporated to give
crude product. The crude product was purified by preparative HPLC
(Waters XBridge Prep C18 OBD column, 5.mu. silica, 50 mm diameter,
150 mm length), using decreasingly polar mixtures of water
(containing 0.1% formic acid) and 3:1 MeOH/MeCN as eluents.
Fractions containing the desired compound were evaporated to
dryness to afford
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)-N--
methylacetamido)-2-methylpropanoic acid (21.60 mg, 5.61%) as a
white solid.
[0451] .sup.1H NMR (400.132 MHz, CDCl.sub.3) d1.18 (1H, s),1.46
(3H, s),2.64 (3H, s),2.92 (3H, s),2.99 (3H, s),3.42 (3H, s),3.71
(2H, s),6.37 (1H, s),7.16 (1H, d), 7.25 (1H, d), 7.34 (1H, s),7.46
(2H, d), 7.55 (2H, d), 7.77 (1H, s). m/z (ES+), (M+H)+=495
Intermediate 18-1: Benzyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)-N--
methylacetamido)-2-methylpropanoate
##STR00104##
[0453] A mixture of benzyl 2-methyl-2-(methylamino)propanoate (118
mg, 0.57 mmol) and N-ethyl-N-isopropylpropan-2-amine (99 .mu.L,
0.57 mmol) in DMF (342 .mu.L) were treated with a solution of
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetic
acid (Example 1; 205 mg, 0.52 mmol),
1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (124
mg, 0.65 mmol), 1H-benzo[d][1,2,3]triazol-1-ol (70.0 mg, 0.52 mmol)
and N-ethyl-N-isopropylpropan-2-amine (99 .mu.L, 0.57 mmol) in DMF
(2049 .mu.L) at RT. The resulting solution was stirred at RT for 20
hours. The reaction mixture was evaporated to dryness and
redissolved in DCM (5 mL), and washed with water (5 mL). The
organic layer was evaporated to afford crude product which was used
without further purification.
[0454] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 1.41 (6H, s),
2.59 (1H, s), 2.66 (3H, s), 2.81 (11H, s), 2.88 (11H, s), 2.93 (3H,
d), 2.94 (3H, s), 3.67 (2H, s), 4.63 (3H, s), 5.08 (2H, s), 7.20
(5H, d), 7.23 (1H, s), 7.24 (1H, s), 7.25-7.26 (2H, m), 7.29 (1H,
s), 7.28-7.30 (8H, m), 7.49 (2H, d), 7.59 (2H, d), 7.94 (4H, s).
m/z (ES+), (M+H)+=585
Example 19
1-(2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acet-
yl)piperidine-4-carboxylic acid
##STR00105##
[0456] Potassium hydroxide (91 mg, 1.63 mmol) was added in one
portion to ethyl
1-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4--
yl)acetyl)piperidine-4-carboxylate (Intermediate 19-1; 290.7 mg,
0.54 mmol) in t-BuOH (3505 .mu.L) at RT. The resulting solution was
stirred at 45.degree. C. for 5 hours a precipitate formed. The
reaction mixture was quenched with 2M HCl (5 mL), The reaction
mixture was evaporated to dryness and redissolved in water (10 mL),
and filtered through nylon, washed with water and dried under
vacuum. The crude product was purified by preparative HPLC (Waters
XBridge Prep C18 OBD column, 5.mu. silica, 50 mm diameter, 150 mm
length), using decreasingly polar mixtures of water (containing
0.1% formic acid) and MeCN as eluents. Fractions containing the
desired compound were evaporated to dryness to afford
1-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tyl)piperidine-4-carboxylic acid (59.8 mg, 21.71%) as a white
solid.
[0457] .sup.1H NMR (400.132 MHz, CDCl.sub.3) d1.55-1.68 (1H,
m),1.82-1.98 (2H, m),2.50-2.59 (1H, m), 2.66 (3H, s),2.89 (1H,
s),2.92 (3H, s),3.14 (1H, t), 3.42 (2H, s),3.70 (2H, s),3.82 (1H,
d), 4.38 (1H, d), 5.90 (1H, s),7.17 (1H, s),7.29 (1H, d), 7.34 (1H,
s),7.51 (2H, d), 7.59 (2H, d), 7.78 (1H, s). m/z (ES+), M+=507
Intermediate 19-1: Ethyl
1-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tyl)piperidine-4-carboxylate
##STR00106##
[0459] A mixture of ethyl piperidine-4-carboxylate (90 mg, 0.57
mmol) and N-ethyl-N-isopropylpropan-2-amine (99 .mu.L, 0.57 mmol)
in DMF (342 .mu.L) were treated with a solution of
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetic
acid (Example 1; 205 mg, 0.52 mmol),
1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (124
mg, 0.65 mmol), 1H-benzo[d][1,2,3]triazol-1-ol (70.0 mg, 0.52 mmol)
and N-ethyl-N-isopropylpropan-2-amine (99 .mu.L, 0.57 mmol) in DMF
(2049 .mu.L) at RT. The resulting solution was stirred at RT for 20
hours. The reaction mixture was evaporated to dryness and
redissolved in DCM (5 mL), and washed with water (5 mL). The
organic layer was evaporated to afford ethyl
1-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4--
yl)acetyl)piperidine-4-carboxylate (291 mg, 105%) which was used
without further purification.
[0460] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 1.19 (3H, t),
2.59 (1H, s), 2.66 (3H, s), 2.81-2.81 (5H, m), 2.88-2.93 (8H, m),
3.68 (2H, s), 4.08 (2H, t), 5.23 (4H, s), 7.18 (1H, s), 7.19 (3H,
s), 7.28 (1H, s), 7.33 (1H, d), 7.50-7.52 (2H, m), 7.58-7.60 (2H,
m), 7.95 (2H, s). m/z (ES+), (M+H)+=535
Example 20
2-(2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acet-
amido)acetic acid
##STR00107##
[0462] Powdered potassium hydroxide (106 mg, 1.89 mmol) was added
in one portion to methyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)acetate (Intermediate 20-1; 294 mg, 0.63 mmol) in
tert-butanol (4062 .mu.L) at 45.degree. C. The resulting solution
was stirred at 45.degree. C. for 150 minutes, a thick white
suspension slowly precipitate formed. 2M HCl (5 mL) was added and
the mixture was evaporated to remove the organic solvent. The
reaction mixture was diluted with EtOAc and water, the organic
layer was collected, dried with MgSO.sub.4 and evaporated to afford
crude product. This was purified by preparative HPLC (Waters
XBridge Prep C18 OBD column, 5.mu. silica, 50 mm diameter, 150 mm
length), using decreasingly polar mixtures of water (containing
0.1% formic acid) and MeCN as eluents. Fractions containing the
desired compound were evaporated to dryness to afford
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)acetic acid (56.8 mg, 19.92%) as a white solid.
[0463] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.72 (3H, s),2.83
(3H, s),3.64 (2H, s),3.85 (2H, d), 7.13 (1H, s),7.41 (1H, d), 7.49
(1H, d), 7.63 (2H, d), 7.68 (1H, s),7.91 (2H, d), 8.10 (1H, s),8.52
(1H, t). m/z (ES-), M-=451
Intermediate 20-1: methyl
2-(2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)acetate
##STR00108##
[0465] A solution of
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetic
acid (Example 1; 250 mg, 0.63 mmol),
1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (151
mg, 0.79 mmol), 1H-benzo[d][1,2,3]triazol-1-ol (85 mg, 0.63 mmol)
and N-ethyl-N-isopropylpropan-2-amine (242 .mu.L, 1.39 mmol) in DMF
(2499 .mu.L) was treated with a solution of methyl 2-aminoacetate
hydrochloride (87 mg, 0.69 mmol) in DMF (417 .mu.L) at 23.degree.
C. The resulting solution was stirred at RT for 4 hours. The
reaction mixture was evaporated to dryness and redissolved in EtOAc
(25 mL), and washed sequentially with saturated brine (50 mL) and
water (50 mL). The organic layer was dried over MgSO.sub.4,
filtered and evaporated to afford methyl
2-(2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)ace-
tamido)acetate (266 mg, 90%) which was used without further
purification.
[0466] .sup.1H NMR (400.13 MHz, DMSO-d6) .delta. 1.18 (2H, t), 2.00
(2H, s), 2.60 (1H, s), 2.67 (4H, d), 2.67-2.67 (1H, m), 2.76 (5H,
t), 3.59 (2H, s), 3.65 (3H, s), 3.89-3.90 (2H, m), 4.04 (1H, d),
7.36 (1H, d), 7.43-7.45 (1H, m), 7.53 (1H, s), 7.57-7.59 (2H, m),
7.72 (1H, d), 7.85-7.87 (2H, m), 7.99 (1H, d). m/z (ES+),
(M+H)+=467
Example 21
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)pro-
panoic acid
##STR00109##
[0468] Potassium hydroxide (0.396 g, 7.05 mmol) was added in one
portion to methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphen-
yl-4-yl)propanoate (Intermediate 21-1; 1 g, 2.35 mmol) in t-BuOH
(15.16 mL) at room temperature. The resulting solution was stirred
at 45.degree. C. for 5 hours, a precipitate formed. The reaction
mixture was quenched with 2M HCl (5 mL), evaporated to dryness and
redissolved in water (10 mL), filtered through nylon, washed with
water and dried under vacuum to afford product as a white solid.
The product was purified by preparative HPLC (Waters XBridge Prep
C18 OBD column, 5.mu. silica, 50 mm diameter, 150 mm length), using
decreasingly polar mixtures of water (containing 0.1% formic acid)
and MeCN/MeOH as eluents. Fractions containing the desired compound
were evaporated to dryness to afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)pr-
opanoic acid (0.530 g, 54.8%) as a white powder.
[0469] .sup.1H NMR (400.132 MHz, DMSO) .delta. 1.50 (3H, d), 2.71
(3H, s),2.83 (3H, s),3.86-3.94 (1H, m), 7.27 (2H, d), 7.66 (2H, d),
7.68 (1H, s),7.95 (2H, d), 8.12 (1H, s),12.65 (1H, s). m/z (ES+),
(M+H)+=412
Intermediate 21-1: methyl
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)pr-
opanoate
##STR00110##
[0471] A solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenylboronic acid (175 mg,
0.65 mmol) and methyl
2-(3,5-difluoro-4-(trifluoromethylsulfonyloxy)phenyl)propanoate
(Intermediate 21-2; 200 mg, 0.57 mmol) and Sodium carbonate (0.467
mL, 0.93 mmol), tetrakis(triphenylphosphine)palladium(0) (41.1 mg,
0.04 mmol) and lithium chloride (42.6 mg, 1.01 mmol) in DME (14.300
mL) was degassed and then stirred at 85.degree. C. for 17 hours.
The reaction mixture was partitioned between EtOAc (10 mL) and
saturated brine (15 mL). The organic layer was dried over
MgSO.sub.4, filtered and evaporated to afford crude product. The
crude product was purified by flash silica chromatography, elution
gradient 0 to 50% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)pr-
opanoate (164 mg, 67.1%) as a white solid.
[0472] .sup.1H NMR (400.132 MHz, CDCl.sub.3) d1.53-1.57 (3H,
m),2.72 (3H, s),3.00 (3H, s),3.73 (3H, s), 3.76 (1H, q), 5.46 (1H,
s),7.00 (2H, d), 7.59 (2H, d), 7.68 (2H, d), 7.80 (1H, s). m/z
(ES+), (M+H)+=426
Intermediate 21-2: Methyl
2-(3,5-difluoro-4-(trifluoromethylsulfonyloxy)phenyl)propanoate
##STR00111##
[0474] Triethylamine (4.82 mL, 34.55 mmol) was added dropwise to
methyl 2-(3,5-difluoro-4-hydroxyphenyl)propanoate (Intermediate
21-3; 2.49 g, 11.52 mmol) and trifluoromethanesulfonic anhydride
(2.91 mL, 17.28 mmol) in DCM (49.9 mL) at 0.degree. C. under
nitrogen. The resulting solution was stirred at 0.degree. C. for 2
hours. The reaction mixture was diluted with water (50 mL), and
washed sequentially with saturated NaHCO.sub.3 (100 mL) and
saturated brine (100 mL). The organic layer was dried over
MgSO.sub.4, filtered and evaporated to afford crude product. The
crude product was purified by flash silica chromatography, elution
gradient 0 to 60% EtOAc in isohexane. Pure fractions were
evaporated to dryness to afford methyl
2-(3,5-difluoro-4-(trifluoromethylsulfonyloxy)phenyl)propanoate
(3.13 g, 78%) as an orange oil.
[0475] .sup.1H NMR (400.132 MHz, CDCl.sub.3) d1.44 (3H, d), 3.64
(3H, s),3.64 (1H, q), 6.98 (2H, d)
Intermediate 21-3: Methyl
2-(3,5-difluoro-4-hydroxyphenyl)propanoate
##STR00112##
[0477] tribromoborane (7.37 mL, 77.99 mmol) was added dropwise to
2-(3,5-difluoro-4-methoxyphenyl)propanoic acid (Intermediate 21-4;
2.81 g, 13.00 mmol) in dichloromethane (96 mL) at 0.degree. C.
under nitrogen. The resulting solution was stirred at 0.degree. C.
for 1 hour. The reaction mixture was added dropwise to methanol
(26.3 mL, 649.92 mmol) (--care reaction is vigorous and
exothermic--MeOH kept in ice bath) and the mixture was stirred for
a further 20 minutes. The reaction mixture was evaporated to
dryness and redissolved in DCM (50 mL), and washed sequentially
with saturated NaHCO.sub.3 (50 mL) and water (50 mL). The organic
layer was dried with MgSO.sub.4 and evaporated to afford desired
product methyl 2-(3,5-difluoro-4-hydroxyphenyl)propanoate (2.490 g,
89%).
[0478] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.46 (3H, d),
3.62 (1H, q), 3.68 (3H, s), 5.10 (1H, s), 6.87 (2H, d). m/z (ES-),
(M-H)-=215
Intermediate 21-4: 2-(3,5-Difluoro-4-methoxyphenyl)propanoic
acid
##STR00113##
[0480] Lithium bis(trimethylsilyl)amide (25.4 mL, 25.35 mmol) was
added to 2-(3,5-difluoro-4-methoxyphenyl)acetic acid (2.5 g, 12.37
mmol) in THF (60.8 mL) cooled to 0.degree. C. under nitrogen. The
resulting solution was stirred at 0.degree. C. for 30 minutes. Next
Methyl iodide (0.925 mL, 14.84 mmol) was added and the reaction
stirred for 30 minutes Ammonium chloride (satd) (50 mL) added with
vigorous stirring, ethyl acetate (100 mL) and water (50 mL) were
added and the organic phase separated, washed with water (50 mL)
and saturated brine (50 mL). The aq layer was acidified with 2M HCl
(50 mL) and extracted with ethyl acetate. The organic layers were
combined and dried over MgSO.sub.4, filtered and evaporated to
afford 2-(3,5-difluoro-4-methoxyphenyl)propanoic acid (2.81 g,
105%) which was used without further purification.
[0481] .sup.1H NMR (400.132 MHz, CDCl.sub.3) d1.33 (3H, d), 3.49
(1H, q), 3.82 (3H, s),6.72 (2H, d). m/z (ES-), (M-H)-=215
Example 22
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2,2'-dichlorobiphenyl-4-yl)ac-
etic acid
##STR00114##
[0483] Powdered potassium hydroxide (0.045 g, 0.81 mmol) was added
in one portion to methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,2'-dichlorobiphenyl-4-yl)a-
cetate (Intermediate 22-1; 0.12 g, 0.27 mmol) in tert-butanol (2.00
mL) at 40.degree. C. under nitrogen. The resulting suspension was
stirred at 40.degree. C. for 20 minutes. A thick precipitate formed
so the reaction was quenched with HCl (1.620 mL, 1.62 mmol) in
ethanol (20.0 mL) and the resulting solution stirred for a further
20 minutes before being evaporated to dryness. The resulting solid
was partitioned between water (5 mL) and EtOAc (15 mL). The aqueous
layer showed a pH=4-5. The organic layer was separated and the
aqueous re-extracted with EtOAc (2.times.5 mL). The combined
organics were washed with brine (15 mL), dried over MgSO.sub.4 and
evaporated in vacuo to give product. This was washed with ether (5
mL) and dried under vacuum at room temperature to give an off white
solid. The crude product was purified by preparative HPLC
(Waters--Xbridge Prep C18 5 .mu.m), using decreasingly polar
mixtures of water (containing 0.1% ammonia) and {MeOH(3):MeCN(1)}
as eluents. Fractions containing the desired compound were
evaporated to dryness to afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,2'-dichlorobiphenyl-
-4-yl)acetic acid (0.063 g, 51.7%) as a colourless solid.
[0484] .sup.1H NMR (400.13 MHz, DMSO-d6) .delta. 0.88-2.53 (1H, m),
2.65 (3H, s), 2.76 (3H, s), 3.55 (2H, s) assumed to be this--masked
by a broad peak which is assumed to be due to water etc, 7.29-7.34
(2H, m), 7.45-7.49 (2H, m), 7.62-7.67 (1H, m), 7.78-7.81 (1H, m),
7.99 (1H, d), 8.12 (1H, s). m/z (ES+) (M+H)+=430.07
Intermediate 22-1: Methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,2'-dichlorobiphenyl-4-yl)a-
cetate
##STR00115##
[0486] A solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorophenylboronic acid
(Intermediate 5-1; 450 mg, 1.47 mmol), methyl
2-(3-chloro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(Intermediate 1-2; 490 mg, 1.47 mmol) and tripotassium phosphate
(469 mg, 2.21 mmol) in DME (6 mL), ethanol (3 mL) and water (1.5
mL) was put under vacuum and refilled with nitrogen before addition
of (1,1'-bis(diphenylphosphino)ferrocene)-dichloropalladium(II)
(DCM adduct) (97 mg, 0.12 mmol). The reaction mixture was heated to
and left to stir overnight for 16 hrs. The reaction mixture was
allowed to cool to room temperature and then evaporated. The
residue was partitioned between water (20 mL) and EtOAc (50 mL).
The aqueous was re-extracted with EtOAc (2.times.10 mL) and the
combined organics washed with brine (20 mL), dried (MgSO.sub.4) and
evaporated to give crude product. The crude product was purified by
flash silica chromatography, elution gradient 0 to 50% EtOAc in
isohexane on 40 g silicycle column (eluted of at 50%). Pure
fractions were evaporated to dryness to afford ethyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,2'-dichlorobiphenyl-4-yl)a-
cetate (130 mg, 19.26%) as a white solid. Trans esterification
occurred during the reaction giving the product as an ethyl rather
than methyl ester.
[0487] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 1.30 (3H, t),
2.73 (3H, s), 3.01 (3H, s), 3.67 (2H, m), 4.21 (2H, q), 5.58 (1H,
s), 7.29 (2H, s), 7.40 (1H, d), 7.46 (1H, t), 7.53-7.56 (1H, m),
7.72 (1H, d), 7.78 (1H, s). m/z (ES+) (M+H)+=458
Example 23
6-(2'-Chloro-4'-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)methyl)biphenyl-4--
yl)-3,5-dimethylpyrazine-2-carboxamide
##STR00116##
[0489] To a degassed solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenylboronic acid
(Intermediate 5-1; 562 mg, 2.07 mmol) in DME (60 mL), methanol (15
mL) and water (15 mL) was added tripotassium phosphate (660 mg,
3.11 mmol), 3-(4-bromo-3-chlorobenzyl)-1,2,4-oxadiazol-5(4H)-one
(Intermediate 23-1; 600 mg, 2.07 mmol) followed by
(1,1'-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) (DCM
adduct) (341 mg, 0.41 mmol). The resulting mixture was stirred at
80.degree. C. under nitrogen for 90 minutes. The reaction mixture
was allowed to cool to ambient temperature evaporated and
partitioned between DCM (100 mL) and 0.5M HCl (100 mL), the
suspension was filtered (difficult as most of the material was a
sticky gum) and the resultant material retained. Organic phase
separated off, dried by passing through a phase separating
cartridge. Removal of the solvent under reduced pressure gave crude
product which was combined with previously filtered material for
chromatography. The crude product was purified by preparative HPLC
(Waters--Xbridge Prep C18 5 .mu.m), using decreasingly polar
mixtures of water (containing 0.1% formic acid) and
{MeOH(3):MeCN(1)} as eluents. Fractions containing the desired
compound were evaporated to dryness to afford
6-(2'-chloro-4'-((5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)methyl)bi-
phenyl-4-yl)-3,5-dimethylpyrazine-2-carboxamide (269 mg, 29.8%) as
a colourless solid.
[0490] .sup.1H NMR (400.13 MHz, DMSO-d6) .delta. 2.65 (3H, s), 2.76
(3H, s), 3.99 (2H, s), 7.38-7.40 (1H, m), 7.48 (1H, d), 7.56-7.62
(5H, m), 7.84-7.87 (2H, m), 8.04 (1H, s) m/z (ES-)
(M-H)-=434.57
Intermediate 23-1:
3-(4-Bromo-3-chlorobenzyl)-1,2,4-oxadiazol-5(4H)-one
##STR00117##
[0492] (Z)-Phenyl
2-(4-bromo-3-chlorophenyl)-1-(hydroxyimino)ethylcarbamate
(Intermediate 23-2; 2 g, 5.21 mmol) was dissolved in anhydrous
toluene (65.2 mL). The resulting solution was stirred at reflux for
16 hours. The cooled reaction mixture was evaporated to dryness and
redissolved in DCM (50 mL) and extracted with saturated NaHCO.sub.3
(50 mL). The aqueous layer was acidified with 2M HCl and extracted
with EtOAc (3.times.50 mL). The organic layers were combined and
dried over MgSO.sub.4, filtered and evaporated to afford crude
product. The crude product was purified by flash silica
chromatography {CombiFlash Companion--Presearch Ltd}, column
size=120 g, flow rate=85 mL/min, elution gradient 0 to 10% MeOH in
DCM}. Pure fractions were evaporated to dryness to afford
3-(4-bromo-3-chlorobenzyl)-1,2,4-oxadiazol-5(4H)-one (1.240 g, 82%)
as a colourless solid.
[0493] .sup.1H NMR (400.132 MHz, DMSO) .delta. 3.91 (2H, s),
7.20-7.24 (1H, m), 7.61 (1H, d), 7.74 (1H, d), 12.00-12.50 (1H,
broad singlet). m/z (ES-) (M-H)-=287.36
Intermediate 23-2: (Z)-Phenyl
2-(4-bromo-3-chlorophenyl)-1-(hydroxylamino)ethylcarbamate
##STR00118##
[0495] Triethylamine (0.889 mL, 6.38 mmol) was added to
(Z)-2-(4-bromo-3-chlorophenyl)-N-hydroxyacetimidamide (Intermediate
23-3; 1.4 g, 5.31 mmol) in dry dichloromethane (131 mL) at
0.degree. C. The resulting yellow solution was stirred at 0.degree.
C. for 1 hour. Phenyl chloroformate (0.815 mL, 6.38 mmol) was added
and the reaction mixture stirred at 0.degree. C. for a further 1
hour. The solution was washed sequentially with saturated
Na.sub.2CO.sub.3 (50 mL) and water (50 mL.times.2). The organic
layer was dried over MgSO.sub.4, filtered and evaporated to afford
crude product .about.(Z)-phenyl
2-(4-bromo-3-chlorophenyl)-1-(hydroxyimino)ethylcarbamate (2.70 g,
132%). Used without further purification
Intermediate 23-3:
(Z)-2-(4-Bromo-3-chlorophenyl)-N'-hydroxyacetimidamide
##STR00119##
[0497] 2-(4-Bromo-3-chlorophenyl)acetonitrile (Intermediate 23-4;
2.4 g, 10.41 mmol) in ethanol (15 mL) was added dropwise to
potassium carbonate (8.92 g, 64.56 mmol) and hydroxylamine
hydrochloride (0.724 g, 10.41 mmol) in ethanol (15 mL) at reflux
over a period of 5 minutes. The resulting suspension was stirred at
reflux for 8 hours. The reaction mixture was allowed to cool
overnight and the salts were filtered and washed with DCM
(2.times.50 mL). The filtrate was evaporated to give crude product.
The crude product was purified by flash Silica chromatography
{CombiFlash Companion--Presearch Ltd}, column size=120 g, flow
rate=85 mL/min, elution gradient 0 to 10% MeOH in DCM}. Pure
fractions were evaporated to dryness to afford
(Z)-2-(4-bromo-3-chlorophenyl)-N-hydroxyacetimidamide (1.4 g,
51.0%) as a pale brown oil which slowly crystalised.
[0498] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 3.39 (2H, s),
4.48 (2H, s), 5.30 (0.5H, s), 7.03-7.06 (1H, m), 7.39 (1H, d),
7.55-7.61 (1H, m)
Intermediate 23-4: 2-(4-Bromo-3-chlorophenyl)acetonitrile
##STR00120##
[0500] Sodium cyanide (10.91 g, 222.52 mmol) in water (10 mL) was
added to a solution of chloroform (20 mL) of
N-benzyl-N,N-diethylethanaminium chloride (25.3 g, 111.26 mmol).
1-Bromo-4-(bromomethyl)-2-chlorobenzene (31.64 g, 111.26 mmol) in
chloroform (5 mL) was added dropwisely at room temperature. The
mixture was stirred at room temperature for 1 h then heated to
45.degree. C. for additional 2 h. The reaction mixture was cooled,
separated into two layers and the organic layer was washed with 0.5
N NaOH then brine. The chloroform layer was dried over sodium
sulfate, filtered and concentrated. The crude product was purified
by flash Silica chromatography {CombiFlash Companion--Presearch
Ltd}, column size=330 g, flow rate=100 mL/min, elution gradient 0
to 100% EtOAc in isohexane over 40 minutes. Pure fractions were
evaporated to dryness to afford
2-(4-bromo-3-chlorophenyl)acetonitrile (2.430 g, 9.48%) as a
orange/yellow oil which solidified on standing.
[0501] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 3.70 (2H, s),
7.09-7.12 (1H, m), 7.45 (1H, d), 7.62-7.64 (1H, m). m/z (ES-)
(M-H)-=228.31; 230.35 & 232.34
Intermediate 23-5: 1-Bromo-4-(bromomethyl)-2-chlorobenzene
##STR00121##
[0503] Benzoic peroxyanhydride (3.73 g, 15.41 mmol) was added to a
degassed mixture of 1-bromo-2-chloro-4-methylbenzene (24.35 g,
118.50 mmol) and 1-bromopyrrolidine-2,5-dione (23.20 g, 130.35
mmol) in CCl.sub.4 (100 mL) at room temperature under nitrogen. The
resulting mixture was stirred at reflux for 18 hrs. The reaction
was cooled and washed with water (equal volume); satd sodium
thiosulfite (equal volume) and water (equal volume). Mixture dried
by passing through a phase separating cartridge. Solvent removed to
give crude 1-bromo-4-(bromomethyl)-2-chlorobenzene (31.7 g, 94%) as
pale brown oil which was progressed without further
purification.
Example 24
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)ace-
tic acid
##STR00122##
[0505] Powdered potassium hydroxide (0.039 g, 0.70 mmol) was added
in one portion to methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)ac-
etate (Intermediate 24-1; 0.096 g, 0.23 mmol) in tert-butanol (2.00
mL) at 40.degree. C. under nitrogen. The resulting suspension was
stirred at 40.degree. C. for 20 minutes. A thick precipitate formed
so the reaction was quenched with aq 1M HCl (1.4 mL, 1.40 mmol) and
the resulting solution stirred for a further 20 minutes before
being evaporated to dryness. The resulting solid was partitioned
between water (5 mL) and EtOAc (15 mL). The organic layer was
separated and the aqueous re-extracted with EtOAc (2.times.5 mL).
The combined organics were washed with brine (15 mL), dried over
MgSO.sub.4 and evaporated in vacuo to give product. The crude
product was purified by preparative HPLC (Waters--Xbridge Prep C18
5 .mu.m), using decreasingly polar mixtures of water (containing
0.1% formic acid) and {MeOH(3):MeCN(1)} as eluents. Fractions
containing the desired compound were evaporated to dryness to
afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl--
4-yl)acetic acid (0.052 g, 56.0%) as a colourless solid.
[0506] .sup.1H NMR (400.13 MHz, DMSO-d6) .delta. 2.65 (3H, s), 2.76
(3H, s), 3.71 (2H, s), 7.16-7.21 (2H, m), 7.59 (3H, d), 7.87-7.89
(2H, m), 8.05 (1H, s). m/z (ES+) (M+H)+=398.22
Intermediate 24-1: Methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)ac-
etate
##STR00123##
[0508] A solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenylboronic acid (243 mg,
0.90 mmol), methyl
2-(3,5-difluoro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(Intermediate 24-2; 300 mg, 0.90 mmol) and tripotassium phosphate
(286 mg, 1.35 mmol) in butyronitrile (2 mL) was put under vacuum
and refilled with nitrogen before addition of
(1,1'-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) (DCM
adduct) (59.1 mg, 0.07 mmol). The reaction mixture was heated in
the microwave at 150.degree. C. for 6 hours.
[0509] The reaction mixture was concentrated and diluted with DCM
(25 mL), and washed with water (2.times.25 mL). The organic layer
was dried by passing through a phase seperating cartridge and
evaporated to afford crude product. The crude product was purified
by flash Silica chromatography {CombiFlash Companion--Presearch
Ltd}, column size=12 g, flow rate=30 mL/min, elution gradient 0 to
50% EtOAc in isohexane. Pure fractions were evaporated to dryness
to afford methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)ac-
etate (96 mg, 26.0%) as a slightly coloured (purple tinge)
solid.
[0510] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 2.72 (3H, s),
3.00 (3H, s), 3.67 (2H, s), 3.76 (3H, s), 5.47 (1H, s), 6.96-7.01
(2H, m), 7.59-7.61 (2H, m), 7.67-7.70 (2H, m), 7.81 (1H, s). m/z
(ES+) M+=412.37
Intermediate 24-2: Methyl
2-(3,5-difluoro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
##STR00124##
[0512] Trifluoromethanesulphonic anhydride (0.854 mL, 5.21 mmol)
was added dropwise to a stirred solution of methyl
2-(3,5-difluoro-4-hydroxyphenyl)acetate (Intermediate 24-3; 0.702
g, 3.47 mmol) in DCM (15.06 mL) cooled to 0.degree. C., over a
period of 5 minutes under nitrogen. Triethylamine (1.452 mL, 10.42
mmol) was added dropwise over 5 minutes (keeping internal
temperature between 5-10.degree. C.) and the resulting solution
stirred at room temperature for 4 hours under nitrogen. The
reaction mixture was diluted with DCM (100 mL), and washed
sequentially with water (100 mL), saturated NaHCO.sub.3 (100 mL),
and water (100 mL). The organic layer was dried by passing through
a phase seperating cartridge and evaporated to afford crude
product. The crude product was purified by flash silica
chromatography, elution gradient 0 to 20% EtOAc in isohexane. Pure
fractions were evaporated to dryness to afford methyl
2-(3,5-difluoro-4-(trifluoromethylsulfonyloxy)phenyl)acetate (0.930
g, 80%) as a straw yellow oil.
[0513] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 3.63 (2H, s),
3.74 (3H, s), 7.02-7.06 (2H, m)
Intermediate 24-3: Methyl
2-(3,5-difluoro-4-hydroxyphenyl)acetate
##STR00125##
[0515] Tribromoborane (2.357 mL, 24.93 mmol) was added dropwise to
2-(3,5-difluoro-4-methoxyphenyl)acetic acid (0.84 g, 4.16 mmol) in
dichloromethane (5 mL) at ambient temperature under nitrogen. The
resulting solution was stirred at ambient temperature for 16 hours.
Methanol (8.41 mL, 207.76 mmol) was added dropwise (--care reaction
is vigorous and exothermic--mixture maintained a reflux during the
addition) and the mixture was stirred for a further 20 minutes. The
reaction mixture was evaporated to dryness and redissolved in DCM
(50 mL), and washed sequentially with saturated NaHCO3 (50 mL) and
water (50 mL). The organic layer was dried by passing through a
phase seperating cartridge and evaporated to afford desired product
methyl 2-(3,5-difluoro-4-hydroxyphenyl)acetate (0.660 g, 79%).
[0516] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 3.52 (2H, s),
3.71 (3H, s), 5.32 (1H, s), 6.81-6.86 (2H, m). m/z (ES-)
(M-H)-=201.27; HPLC tR=1.78 min
Example 25
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorobiphenyl-4-yl)acetic
acid
##STR00126##
[0518] Powdered potassium hydroxide (72.7 mg, 1.30 mmol) was added
in one portion to methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorobiphenyl-4-yl)acetat-
e (Intermediate 25-1; 170 mg, 0.43 mmol) in tert-butanol (2.0 mL)
at 40.degree. C. under nitrogen. The resulting suspension was
stirred at 40.degree. C. for 20 minutes. A thick precipitate formed
so the reaction was quenched with acetic acid (0.124 mL, 2.16 mmol)
in ethanol (20.0 mL) and the resulting solution stirred for a
further 20 minutes before being evaporated to dryness. The
resulting solid was partitioned between water (5 mL) and EtOAc (15
mL). The aqueous layer showed a pH=4-5. The organic layer was
separated and the aqueous re-extracted with EtOAc (2.times.5 mL).
The combined organics were washed with brine (15 mL), dried over
MgSO.sub.4 and evaporated in vacuo to give product. This was washed
with Ether (5 mL) and dried under vacuum at room temperature to
give an off white solid. The crude product was purified by
preparative HPLC (Waters--Xbridge Prep C18 5 .mu.m), using
decreasingly polar mixtures of water (containing 0.1% formic acid)
and {MeOH(3):MeCN(1)} as eluents. Fractions containing the desired
compound were evaporated to dryness to afford
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorobiphenyl-4-yl-
)acetic acid (80 mg, 48.8%) as a colourless
[0519] .sup.1H NMR (400.13 MHz, DMSO-d6) .delta. 2.64 (3H, s), 2.76
(3H, s), 3.67 (2H, s), 7.21-7.27 (2H, m), 7.56 (2H, t), 7.67-7.69
(2H, m), 7.85-7.87 (2H, m), 8.03 (1H, s) m/z (ES+)
(M+H)+=380.22
Intermediate 25-1: Methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorobiphenyl-4-yl)acetat-
e
##STR00127##
[0521] A solution of
3,5-dimethyl-6-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pyr-
azine-2-carboxamide (353 mg, 1 mmol), methyl
2-(3-fluoro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(Intermediate 25-2; 411 mg, 1.30 mmol) and tripotassium phosphate
(318 mg, 1.50 mmol) in DME (6 mL), ethanol (3.00 mL) and water
(1.500 mL) was put under vacuum and refilled with nitrogen before
addition of
(1,1'-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) (DCM
adduct) (65.8 mg, 0.08 mmol). The reaction mixture was heated to
and left to stir overnight for 16 hrs. The reaction mixture was
allowed to cool to room temperature and then evaporated. The
residue was partitioned between water (20 mL) and EtOAc (50 mL).
The aqueous was re-extracted with EtOAc (2.times.10 mL) and the
combined organics washed with brine (20 mL), dried (MgSO.sub.4) and
evaporated to give crude product. The crude product was purified by
flash silica chromatography, elution gradient 0 to 50% EtOAc in
isohexane on 40 g silicycle column. Pure fractions were evaporated
to dryness to afford methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorobiphenyl-4-yl)acetat-
e (180 mg, 45.8%) as a white solid.
[0522] .sup.1H NMR (400.13 MHz, DMSO-d6) .delta. 2.64 (3H, s), 2.79
(3H, s), 3.68 (3H, s), 3.77 (2H, s), 7.23-7.25 (2H, m), 7.55 (1H,
t), 7.67-7.70 (2H, m), 7.80-7.82 (2H, m). m/z (ES+)
(M+H)+=394.37
Intermediate 25-2: Methyl
2-(3-fluoro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
##STR00128##
[0524] Trifluoromethanesulphonic anhydride (2.67 mL, 16.29 mmol)
was added dropwise to a stirred solution of methyl
2-(3-fluoro-4-hydroxyphenyl)acetate (85% by LCMS) (2 g, 10.86 mmol)
in DCM (47.1 mL) cooled to 0.degree. C., over a period of 5 minutes
under nitrogen. Triethylamine (4.54 mL, 32.58 mmol) was added
dropwise over 5 minutes (keeping internal temperature between
5-10.degree. C.) and the resulting solution stirred at room
temperature for 4 hours under nitrogen. The reaction mixture was
diluted with DCM (100 mL), and washed sequentially with water (100
mL), saturated NaHCO.sub.3 (100 mL), and water (100 mL). The
organic layer was dried by passing through a phase seperating
cartridge and evaporated to afford crude product. The crude product
was purified by flash silica chromatography, elution gradient 0 to
20% EtOAc in isohexane. Pure fractions were evaporated to dryness
to afford methyl
2-(3-fluoro-4-(trifluoromethylsulfonyloxy)phenyl)acetate (2.250 g,
65.5%) as a straw yellow oil.
[0525] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 3.64 (2H, s),
3.73 (3H, s), 7.11-7.14 (1H, m), 7.22-7.31 (2H, m). m/z (ES-)
(M-H)-=315.19
Example 26 and Example 27
2-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2'-fluorobiphenyl-4--
yl)propanoic acid enantiomers 1 and 2
##STR00129##
[0527] Powdered potassium hydroxide (432 mg, 7.69 mmol) was added
in one portion to methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2'-fluorobiphenyl-4-
-yl)propanoate (Intermediate 26-1; 680 mg, 1.54 mmol) in
tert-butanol (10 mL). The resulting yellow cloudy suspension was
stirred at 40.degree. C. for 1 hour. The reaction mixture was
quenched with acetic acid (0.705 mL, 12.31 mmol) in ethanol (2 mL)
and the resulting solution stirred for a further 10 minutes before
being evaporated to dryness. The resulting solid was partitioned
between water (20 mL) and DCM (20 mL). The organic layer was
separated and the aqueous re-extracted with DCM (20 mL). The
combined organics were evaporated in vacuo to give crude product as
an off white solid (578 mg). This crude product was purified by
preparative HPLC (Waters XBridge Prep C18 OBD column, 5.mu. silica,
50 mm diameter, 150 mm length), using decreasingly polar mixtures
of water (containing 0.1% formic acid) and MeOH as eluents.
Fractions containing the desired compound were evaporated to
dryness to afford racemic
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2'-fluorobiphenyl-4-
-yl)propanoic acid (359 mg, 54.5%) as a white solid.
[0528] .sup.1H NMR (400.132 MHz, DMSO) .delta. 1.43 (3H, d), 2.67
(3H, s), 2.76 (3H, s), 3.81 (1H, q), 7.42 (2H, m), 7.51 (2H, m),
7.62 (1H, s), 7.70 (1H, m), 7.80 (1H, m), 8.11 (1H, s), 12.51 (1H,
s). m/z (ES+) (M+H)+=428
[0529] Chiral separation of racemic
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2'-fluorobiphenyl-4-
-yl)propanoic acid. The crude product was purified by preparative
chiral-HPLC on a Merck 50 mm 20 .mu.m Chiralpak AD column, eluting
isocratically with 30% EtOH in 70% isohexane (acidified with AcOH
0.2%) as eluent. The fractions containing the desired compounds
were evaporated to dryness and dried under high vacuum overnight to
afford:
(i)
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2'-fluorobiphen-
yl-4-yl)propanoic acid (enantiomer 1) (161 mg, 46.0%) as a white
solid
[0530] .sup.1H NMR (400.132 MHz, DMSO) .delta. 1.44 (3H, d), 2.69
(3H, s), 2.78 (3H, s), 3.83 (1H, q), 7.40 (1H, m), 7.46 (1H, d),
7.53 (2H, m), 7.64 (1H, s), 7.71 (1H, m), 7.81 (1H, m), 8.12 (1H,
s), 12.49 (1H, s).m/z (ES+) (M+H)+=428.10. This enantiomer proved
to be the more potent DGAT1 inhibitor and has been assigned the
S-configuration by analogy to Examples 8 and 9. This was
subsequently confirmed by single crystal diffraction at 200K.
and
(ii)
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2'-fluorobiphe-
nyl-4-yl)propanoic acid (enantiomer 2) (146 mg, 41.7%) as a white
solid.
[0531] .sup.1H NMR (400.132 MHz, DMSO) .delta. 1.44 (3H, d), 2.68
(3H, s), 2.78 (3H, s), 3.82 (1H, q), 7.40 (1H, m), 7.46 (1H, d),
7.53 (2H, m), 7.64 (1H, s), 7.71 (1H, m), 7.81 (1H, m), 8.12 (1H,
s), 12.40 (1H, s). m/z (ES+) (M+H)+=428.17.
[0532] This enantiomer proved to be the less potent DGAT1 inhibitor
and has been assigned the R-configuration by analogy to Examples 8
and 9.
Intermediate 26-1: Methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2'-fluorobiphenyl-4-
-yl)propanoate
##STR00130##
[0534] A solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl
trifluoromethanesulfonate (Intermediate 6-4; 703 mg, 1.79 mmol) and
methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-
propanoate (Intermediate 8-2; 580 mg, 1.79 mmol), lithium chloride
(133 mg, 3.13 mmol) and potassium phosphate, tri-basic (455 mg,
2.14 mmol) in DME (20 mL), methanol (10 mL) and water (5 mL) was
thoughroughly degassed. The mixture was treated with
PdCl.sub.2(dppf)-DCM adduct (73.0 mg, 0.09 mmol), degassed again
and the atmosphere replaced with nitrogen before being heated to
85.degree. C. for 17 hours. The reaction mixture was allowed to
cool and evaporated, the residue was partitioned between EtOAc (100
mL), and water (75 mL) and the aqueous layer was further extracted
with EtOAc (100 mL). The organic layers were combined and washed
with saturated brine (100 mL), dried over MgSO.sub.4, filtered and
evaporated to afford crude product. The crude product was purified
by flash silica chromatography, elution gradient 0 to 60% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2'-fluorobiphenyl-4-
-yl)propanoate (681 mg, 86%) as a cream solid.
[0535] .sup.1H NMR (400.132 MHz, DMSO) .delta. 1.46 (3H, d), 2.66
(3H, s), 2.77 (3H, s), 3.64 (3H, s), 3.95 (1H, q), 7.37-7.40 (1H,
m), 7.45 (1H, d), 7.51 (1H, t), 7.55-7.55 (1H, m), 7.63 (1H, s),
7.69-7.71 (1H, m), 7.78-7.81 (1H, m), 8.11 (1H, s). m/z (ES+)
(M+H)+=442
Example 28
1-(4'-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)cyc-
lopropanecarboxylic acid
##STR00131##
[0537] Powdered potassium hydroxide (91 mg, 1.62 mmol) was added in
one portion to methyl
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)cy-
clopropanecarboxylate (Intermediate 28-1; 142 mg, 0.32 mmol) in
tert-butanol (10 mL). The resulting yellow cloudy suspension was
stirred at 40.degree. C. for 1 hour. The reaction mixture was
quenched with acetic acid (0.149 mL, 2.60 mmol) in ethanol (2 mL)
and the resulting solution stirred for a further 10 minutes before
being evaporated to dryness. The resulting solid was partitioned
between water (20 mL) and ethyl acetate (20 mL). An insoluble solid
was filtered off. The organic layer was separated and the aqueous
re-extracted with ethyl acetate (20 mL). The combined organics were
evaporated in vacuo to give crude product as an off white solid.
The crude solid was triturated with mixture of DCM (3 mL) and
methanol (3 mL) to give a solid which was collected by filtration
and dried under vacuum to give
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)cy-
clopropanecarboxylic acid (52.0 mg, 37.8%) as a white solid.
[0538] .sup.1H NMR (400.132 MHz, DMSO) .delta. 1.30 (2H, m), 1.51
(2H, m), 2.66 (3H, s), 2.79 (3H, s), 7.25 (2H, d), 7.60 (3H, d),
7.89 (2H, d), 8.06 (1H, s), 12.58 (1H, s). m/z (ES+) (M+H)+=424
Intermediate 28-1: Methyl
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)cy-
clopropanecarboxylate
##STR00132##
[0540] A solution of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenylboronic acid (226 mg,
0.83 mmol), methyl
1-(3,5-difluoro-4-(trifluoromethylsulfonyloxy)phenyl)cyclopropanecarboxyl-
ate (Intermediate 28-2; 300 mg, 0.83 mmol), lithium chloride (70.6
mg, 1.67 mmol) and tripotassium phosphate (265 mg, 1.25 mmol) in
butyronitrile (2 mL) was degassed for 10 minutes then put under
vacuum and refilled with nitrogen before addition of
(1,1'-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) (DCM
adduct) (137 mg, 0.17 mmol). The reaction mixture was heated in the
microwave at 150.degree. C. for 1 hours. The crude product was
purified by flash silica chromatography, elution gradient 0 to 90%
EtOAc in isohexane. Pure fractions were evaporated to dryness to
afford methyl
1-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2,6-difluorobiphenyl-4-yl)cy-
clopropanecarboxylate (160 mg, 43.9%)
[0541] .sup.1H NMR (400.132 MHz, DMSO) .delta. 1.34 (2H, q), 1.53
(2H, q), 2.65 (3H, s), 2.76 (3H, s), 3.62 (3H, s), 7.27 (2H, d),
7.59 (3H, d), 7.88 (2H, d), 8.05 (1H, s). m/z (ES+) (M+H)+=438
Intermediate 28-2: Methyl
1-(3,5-difluoro-4-(trifluoromethylsulfonyloxy)phenyl)cyclopropanecarboxyl-
ate
##STR00133##
[0543] Methyl
1-(3,5-difluoro-4-hydroxyphenyl)cyclopropanecarboxylate
(Intermediate 28-3; 635 mg, 2.78 mmol),
1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide
(994 mg, 2.78 mmol) and potassium carbonate (1154 mg, 8.35 mmol)
were suspended in THF (15 mL) and sealed into a microwave tube. The
reaction was heated to 120.degree. C. for 8 minutes in the
microwave reactor and cooled to RT. The suspension was filtered,
the solid was washed with EtOAc (20 mL) and the filtrate was
evaporated to afford crude product. The crude product was purified
by flash silica chromatography, elution gradient 10 to 20% EtOAc in
isohexane. Pure fractions were evaporated to dryness to afford
methyl
1-(3,5-difluoro-4-(trifluoromethylsulfonyloxy)phenyl)cyclopropanecarboxyl-
ate (968 mg, 97%) as a colourless oil.
[0544] .sup.1H NMR (400.132 MHz, DMSO) .delta. 1.35 (2H, m), 1.52
(2H, m), 3.58 (3H, s), 7.55 (2H, m)
Intermediate 28-3: Methyl
1-(3,5-difluoro-4-hydroxyphenyl)cyclopropanecarboxylate
##STR00134##
[0546] Tribromoborane (0.666 ml, 7.04 mmol) was added dropwise to
methyl 1-(3,5-difluoro-4-methoxyphenyl)cyclopropanecarboxylate
(Intermediate 28-4; 1.4216 g, 5.87 mmol) in dichloromethane (46.2
mL) at 0.degree. C. under nitrogen. The resulting solution was
stirred at 0.degree. C. for 1 hour. The reaction mixture was added
dropwise to methanol (11.87 mL, 293.45 mmol) (care reaction is
vigorous and exothermic--MeOH kept in ice bath) and the mixture was
stirred for a further 20 minutes. The reaction mixture was
evaporated to dryness and redissolved in DCM (50 mL), and washed
sequentially with saturated NaHCO.sub.3 (50 mL) and water (50 mL).
The organic layer was dried with MgSO.sub.4 and evaporated to
afford crude product. The crude product was purified by flash
silica chromatography, eluted at 25% EtOAc in isohexane. Pure
fractions were evaporated to dryness to afford methyl
1-(3,5-difluoro-4-hydroxyphenyl)cyclopropanecarboxylate (0.657 g,
49.1%) as a white solid.
[0547] .sup.1H NMR (400.132 MHz, CDCl.sub.3) d1.08 (2H, q), 1.52
(2H, q), 3.57 (3H, s),5.08 (1H, s),6.78-6.86 (2H, m)m/z (ES-),
(M-H)-=227
Intermediate 28-4: Methyl
1-(3,5-difluoro-4-methoxyphenyl)cyclopropanecarboxylate
##STR00135##
[0549] Sodium hydride (0.326 g, 8.14 mmol) was added in one portion
to methyl 2-(3,5-difluoro-4-methoxyphenyl)acetate (1.76 g, 8.14
mmol) in DMF (46.3 mL) at 0.degree. C. under nitrogen. The
resulting suspension was stirred at 0.degree. C. for 10 minutes.
Following this 1,2-dibromoethane (0.772 mL, 8.96 mmol) was added to
the reaction mixture and the solution was stirred for 5 minutes.
Additional sodium hydride (0.326 g, 8.14 mmol) was then added and
the reaction allowed to stir for 2 hours. The reaction mixture was
quenched with saturated NH.sub.4Cl (50 mL). The reaction mixture
was diluted with EtOAc (75 mL), and washed sequentially with water
(4.times.50 mL) and saturated brine (50 mL). The organic layer was
evaporated to afford crude product. The crude product was purified
by flash silica chromatography, elution at 10% EtOAc in isohexane.
Pure fractions were evaporated to dryness to afford methyl
1-(3,5-difluoro-4-methoxyphenyl)cyclopropanecarboxylate (1.540 g,
78%) as a colourless gum.
[0550] .sup.1H NMR (400.132 MHz, CDCl.sub.3) d1.15 (2H, q), 1.60
(2H, q), 3.64 (3H, s),3.98 (3H, s),6.85-6.91 (2H, m)
Example 29
3,5-Dimethyl-6-(2'-methyl-4'-((5-oxo-2,5-dihydro-1,2,4-oxadiazol-3-yl)meth-
yl)biphenyl-4-yl)pyrazine-2-carboxamide
##STR00136##
[0552] 3-(4-Iodo-3-methylbenzyl)-1,2,4-oxadiazol-5(2H)-one
(Intermediate 29-1; 200 mg, 0.63 mmol) and 2M sodium carbonate (aq)
(0.633 mL, 1.27 mmol), tetrakis(triphenylphosphine)palladium(0)
(45.3 mg, 0.04 mmol) in DME (4 mL) was degassed and then stirred at
85.degree. C. for 17 hours under nitrogen. The reaction mixture was
evaporated and partitioned between EtOAc (75 mL) and saturated
brine (15 mL). The organic layer was dried over MgSO.sub.4,
filtered and evaporated to afford crude product. The crude product
was purified by flash silica chromatography, elution gradient 0 to
100% EtOAc in isohexane. Fractions were evaporated to dryness to
afford a cream solid (117 mg). The product was purified by
preparative HPLC (Waters XBridge Prep C18 OBD column, 5.mu. silica,
50 mm diameter, 150 mm length), using decreasingly polar mixtures
of water (containing 0.1% formic acid) and MeOH as eluents.
Fractions containing the desired compound were evaporated to
dryness to afford
3,5-dimethyl-6-(2'-methyl-4'-((5-oxo-2,5-dihydro-1,2,4-oxadiazol-3-yl)met-
hyl)biphenyl-4-yl)pyrazine-2-carboxamide (13 mg, 0.031 mmol,
4.95%)
[0553] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.23 (3H, s), 2.60
(3H, s), 2.70 (3H, s), 3.84 (2H, s), 7.19 (3H, m), 7.41 (2H, d),
7.49 (1H, m), 7.77 (2H, d), 7.98 (1H, s), 12.26 (1H, s). m/z (ES-)
(M-H)-=414
Intermediate 29-1:
3-(4-iodo-3-methylbenzyl)-1,2,4-oxadiazol-5(4H)-one
##STR00137##
[0555] (Z)-Phenyl
1-(hydroxyimino)-2-(4-iodo-3-methylphenyl)ethylcarbamate
(Intermediate 29-2; 1.67 g, 4.07 mmol) was dissolved in anhydrous
toluene (30 mL). The resulting solution was stirred at reflux for
16 hours. The cooled reaction mixture was evaporated to dryness and
redissolved in DCM (50 mL) and extracted with saturated NaHCO.sub.3
(50 mL). The aqueous layer was acidified with 2M HCl and extracted
with EtOAc (3.times.50 mL). The organic layers were combined and
dried over MgSO.sub.4, filtered and evaporated to afford desired
product. 3-(4-iodo-3-methylbenzyl)-1,2,4-oxadiazol-5(4H)-one (0.787
g, 61.2%) as a yellow solid.
[0556] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.34 (3H, s), 3.81
(2H, s), 6.87 (1H, d), 7.27 (1H, s), 7.78 (1H, d), 12.25 (1H, s).
m/z (ES-) (M-H)-=315
Intermediate 29-2: (Z)-Phenyl
1-(hydroxyimino)-2-(4-iodo-3-methylphenyl)ethylcarbamate
##STR00138##
[0558] Triethylamine (0.651 mL, 4.67 mmol) was added to
(Z)-N'-hydroxy-2-(4-iodo-3-methylphenyl)acetimidamide (Intermediate
29-3; 1.13 g, 3.90 mmol) in dry dichloromethane (30 mL) at
0.degree. C. The resulting yellow solution was stirred at 0.degree.
C. for 1 hour. Phenyl chloroformate (0.598 mL, 4.67 mmol) was added
and the reaction mixture stirred at 0.degree. C. for a further 1
hour. The solution was washed sequentially with saturated
Na.sub.2CO.sub.3 (50 mL) and water (50 mL.times.2). The organic
layer was dried over MgSO.sub.4, filtered and evaporated to afford
(Z)-phenyl 1-(hydroxyimino)-2-(4-iodo-3-methylphenyl)ethylcarbamate
(1.675 g, 105%) as crude product.
[0559] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.41 (3H, s), 3.38
(2H, s), 6.69 (1H, s), 6.99 (1H, d), 7.42 (7H, m), 7.82 (1H, d).
m/z (ES+) (M+H)+=411
Intermediate 29-3:
(Z)-N'-hydroxy-2-(4-iodo-3-methylphenyl)acetimidamide
##STR00139##
[0561] 2-(4-Iodo-3-methylphenyl)acetonitrile (2 g, 7.78 mmol) in
ethanol (30 mL) was added dropwise to potassium carbonate (6.67 g,
48.24 mmol) and hydroxylamine hydrochloride (0.541 g, 7.78 mmol) in
ethanol (30 mL) at reflux over a period of 5 minutes. The resulting
suspension was stirred at reflux for 8 hours. The reaction mixture
was allowed to cool overnight and the salts were filtered and
washed with DCM (2.times.50 mL). The filtrate was evaporated to
give crude product. The crude product was purified by flash silica
chromatography on a combi flash companion 40 g cartridge, elution
gradient 0 to 30% MeOH in DCM. Pure fractions were evaporated to
dryness to afford
(Z)-N'-hydroxy-2-(4-iodo-3-methylphenyl)acetimidamide (1.135 g,
50.3%) as a yellow gum.
[0562] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.32 (3H, s), 3.18
(2H, s), 5.35 (2H, s), 6.84 (1H, d), 7.22 (1H, s), 7.70 (1H, d),
8.86 (1H, s). m/z (ES+) (M+H)+=291
Example 30
6-(4'-(2-Amino-2-oxoethyl)-2'-chlorobiphenyl-4-yl)-3,5-dimethylpyrazine-2--
carboxamide
##STR00140##
[0564] Methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chlorobiphenyl-4-yl)acetat-
e (Intermediate 1-1; 60 mg, 0.15 mmol) and ammonia (7M in methanol)
(2091 .mu.L, 14.64 mmol) were sealed into a microwave tube. The
reaction was heated to 140.degree. C. for 1 hour in the microwave
reactor and cooled to RT. Removal of the solvent under reduced
pressure gave crude product. The crude product was purified by
preparative HPLC (Waters--Xbridge Prep C18 5 .mu.m), using
decreasingly polar mixtures of water (containing 0.1% formic acid)
and {MeOH(3):MeCN(1)} as eluents. Fractions containing the desired
compound were evaporated to dryness to afford
6-(4'-(2-amino-2-oxoethyl)-2'-chlorobiphenyl-4-yl)-3,5-dimethylpyrazine-2-
-carboxamide (16.20 mg, 28.0%) as a colourless solid.
[0565] .sup.1H NMR (400.13 MHz, CDCl.sub.3) .delta. 2.73 (3H, s),
3.00 (3H, s), 3.63 (2H, s), 5.49 (3H, s), 7.30 (1H, d), 7.40 (1H,
d), 7.46 (1H, s), 7.57-7.61 (2H, m), 7.67 (2H, d), 7.82 (1H, s) m/z
(ES+) (M+H)+=395.28
Example 31
(2S)-2-[4-[4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-chlo-
rophenyl]propanoic acid
##STR00141##
[0567]
2-[4-[4-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-ch-
lorophenyl]prop-2-enoic acid (Intermediate 31-10; 142 g, 283.44
mmol), bis(1,5-cyclooctadiene)rhodium(I) tetrafluoroborate (1.381
g, 3.40 mmol),
(R)-1-[(Sp)-2-(di-tert-butylphosphino)ferrocenyl]ethylbis(2-methylphenyl)-
phosphine (2.102 g, 3.68 mmol) in degassed methanol (2.5 L) and
degassed toluene (836 mL) were stirred under an atmosphere of
hydrogen at 5 bar and 45.degree. C. for 4 hours. Chiral HPLC
analysis (chiralpak AD 5 .mu.m, 250 mm.times.4.6 mm column, eluted
with 60% isohexane/40% ethanol/0.2% acetic acid, retention time for
required enantiomer 14.5 minutes) indicated the ratio of desired to
undesired enantiomer was 87:13. The solvent was removed in vacuo.
The crude product was dissolved in 5% methanol/dichloromethane and
then chromatographed on silica (5 Kg of Merck lichro prep silica
15-25 .mu.m, 200 mm diameter column), eluting with a solvent
mixture of 5% methanol/dichloromethane. Pure fractions were
evaporated to dryness to afford the mixture of the enantiomers,
chiral prep HPLC chromatography (5 Kg of chiralpak AD 20 .mu.m, 200
mm diameter column, eluted with 70% isohexane/30% ethanol/0.2%
acetic acid, retention time for required enantiomer 17 minutes)
then gave
(2S)-2-[4-[4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-chl-
orophenyl]propanoic acid (58 g, 40%, 99% ee) as a white solid.
[0568] .sup.1H NMR (400 MHz, DMSO-d6) .delta.1.43 (3H d, J=7.2 Hz),
2.66 (3H, s), 2.77 (3H, s), 3.81 (1H q, J=7.1 Hz), 7.38-7.45 (2H,
m), 7.51 (1H t, J=7.8 Hz), 7.54 (1H d, J=1.9 Hz), 7.63 (1H, s),
7.69-7.71 (1H, m), 7.78-7.81 (1H, m), 8.11 (1H, s), 12.51 (1H, s)
m/z (ES+) (M+H)+=428
Intermediate 31-1: Methyl 2-(3-chloro-4-hydroxyphenyl)acetate
##STR00142##
[0570] A solution of 2-(3-chloro-4-hydroxyphenyl)acetic acid (1000
g, 5359 mmol) and sulfuric acid (0.029 L, 535 mmol) in methanol (10
L) was stirred at reflux for 3 hours. The reaction mixture was
cooled to 25.degree. C. The solvent was then removed in vacuo.
Ethyl acetate (5.0 L) was added and the solution was washed with
water (4.0 L), brine (2.0 L), dried (magnesium sulphate), filtered
and the solvent was removed in vacuo. Gave methyl
2-(3-chloro-4-hydroxyphenyl)acetate (1078 g, 99%) as an orange
oil.
[0571] .sup.1H NMR (400 MHz, CDCl.sub.3) .delta. 3.53 (2H, s), 3.70
(3H, s), 5.53 (1H, s), 6.96 (1H, d), 7.08 (1H, dd), 7.25 (1H+CHCl3,
m). m/z (ES-) (M-H)-=199
Intermediate 31-2: Methyl
2-[3-chloro-4-(trifluoromethylsulfonyloxy)phenyl]acetate
##STR00143##
[0573] Pyridine (0.068 L, 841 mmol) was added to a stirred solution
of methyl 2-(3-chloro-4-hydroxyphenyl)acetate (Intermediate 31-1;
150 g, 672 mmol) in toluene (1.0 L) at 25.degree. C. The reaction
was cooled to -5.degree. C. Trifluoromethanesulfonic anhydride (130
mL, 773 mmol) was then added over a period of 45 minutes, keeping
the temperature below 0.degree. C. The reaction was then warmed to
room temperature and the resulting suspension left to stand over
night. The reaction was quenched with sodium phosphate (50 g in 500
mL water). Ethyl acetate (1.0 L) was added. The organic layer was
separated and the aqueous layer extracted with ethyl acetate (1.0
L). The organics were combined and washed with 50% brine/water (500
mL), dried (magnesium sulphate), filtered and the solvent removed
in vacuo. The crude product was then azeoptroped with toluene (1.0
L). Gave 2-[3-chloro-4-(trifluoromethylsulfonyloxy)phenyl]acetate
(209 g, 93%) as a pale orange oil that solidified on standing.
[0574] .sup.1H NMR (400 MHz, DMSO-d6) .delta. 3.64 (3H, s), 3.81
(2H, s), 7.43-7.46 (1H, m), 7.60 (1H d, J=8.5 Hz), 7.71 (1H d,
J=2.1 Hz) m/z (ES-) (M-H)-=331
Intermediate 31-3: Methyl
2-[3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]acetate
##STR00144##
[0576] To a degassed solution of methyl
2-(3-chloro-4-(trifluoromethylsulfonyloxy)phenyl)acetate
(Intermediate 31-2; 865 g, 2600 mmol) in 1,4-dioxane (8.6 L) was
added potassium acetate (766 g, 7800 mmol), bis(pinacolato)diboron
(806 g, 3172 mmol) and PdCl.sub.2(dppf)-CH.sub.2Cl.sub.2 adduct
(37.2 g, 45.5 mmol). The suspension was stirred at 25.degree. C.
for 30 minutes and then heated to reflux for 27 hours, monitoring
by LCMS (230 nm). The reaction was cooled to 25.degree. C., then
filtered through a glass sinter. The solid obtained was washed with
1,4-dioxane (5.0 L) and discarded. The solvent was then removed in
vacuo from the combined filtrates to give the crude product. Gave
methyl
2-[3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]acetate
(1168 g) as a brown sludge, proton NMR strength indicated 52% pure
(therefore 607 g, 75%). The material was used crude in the next
stage.
[0577] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.36 (12H, s),
3.59 (2H, s), 3.68 (3H, s), 7.13-7.16 (1H, m), 7.28-7.28 (1H, m),
7.65 (1H, d)
Intermediate 31-4:
2-Fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol
##STR00145##
[0579] A solution of 4-bromo-2-fluorophenol (143 mL, 1308 mmol) in
dioxane (2.5 L) was degassed with nitrogen for a period of 30
minutes. Potassium acetate (514 g, 5235 mmol),
bis(pinacolato)diboron (399 g, 1570 mmol),
(1,1'-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) (7.54
g, 9.2 mmol) and 1,1'-bis(diphenylphosphino)ferrocene (5.13 g, 9.2
mmol) were then added. The resulting mixture was stirred and heated
to 100.degree. C. under a nitrogen atmosphere. The reaction was
strongly exothermic once the internal temperature had reached
>85.degree. C., after 10 minutes the reaction stopped foaming.
The internal reaction temperature reached reflux
(.about.100.degree. C.) and the reaction was stirred for 20 hours.
The reaction was then cooled to 25.degree. C. Ethyl acetate (2.5 L)
and water (2.5 L) were added then this was filtered through a pad
of celite. The aqueous layer was separated and the organic layer
was washed with 50% brine/water (2.5 L), dried (magnesium
sulphate), filtered and the solvent removed in vacuo. The crude
product was then chromatographed on silica (5 Kg of Merck lichro
prep silica 15-25 .mu.m, 200 mm diameter column), eluting with a
solvent gradient of 0-20% ethylacetate/isohexane. Pure fractions
were evaporated to dryness to afford
2-fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol (348
g) as a yellow solid, proton NMR strength indicated 80% pure
(therefore 278 g, 89%). The material was used crude in the next
stage.
[0580] .sup.1H NMR (400.132 MHz, CDCl.sub.3) .delta. 1.33 (12H, s),
5.38 (1H, s), 6.98 (1H, t), 7.47-7.51 (2H, m) m/z (ES-)
(M-H)-=237
Intermediate 31-5:
6-(3-Fluoro-4-hydroxyphenyl)-3,5-dimethylpyrazine-2-carboxamide
##STR00146##
[0582] A suspension of
2-fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol
(Intermediate 31-4; 348 g, 1169 mmol) (80% strength by proton
NMR),6-chloro-3,5-dimethylpyrazine-2-carboxamide (217 g, 1169 mmol)
and potassium phosphate tribasic (298 g, 1403 mmol) in DME (3.6 L),
ethanol (0.9 L) and water (1.8 L) was stirred. The mixture was
degassed with nitrogen for 30 minutes at 30.degree. C.
Dichloro[1,1'-bis(diphenylphosphino)ferrocene]palladium(II)
dichloromethane adduct (8.60 g, 10.5 mmol) was then added to the
suspension. The reaction was further degassed for 10 minutes before
being heated to 80.degree. C., stirred for 4 hours. The reaction
was cooled to 25.degree. C. The solvents were then removed in vacuo
until a slurry in water remained. A solution of citric acid (640 g)
in water (6.0 L) was then added slowly with stirring. The
suspension was filtered, washed with water (2.times.2.5 L), MTBE
(2.5 L), sucked dry on the sinter and then dried at 65.degree. C.
in a vacuum over for 48 hours. Gave
6-(3-fluoro-4-hydroxyphenyl)-3,5-dimethylpyrazine-2-carboxamide
(295 g, 97%) as a light brown solid.
[0583] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.66 (3H, s), 2.78
(3H, s), 7.11 (1H, t), 7.47 (1H, d), 7.65 (1H, s), 7.70 (1H, d),
8.09 (1H, s), 10.24 (1H, s) m/z (ES+) (M+H)+=262
Intermediate 31-6:
[4-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]trifluoromethane-
sulfonate
##STR00147##
[0585] Potassium carbonate (468 g, 3387 mmol) was added in one go
to a stirred mixture of
6-(3-fluoro-4-hydroxyphenyl)-3,5-dimethylpyrazine-2-carboxamide
(Intermediate 31-5; 295 g, 1129 mmol) and
N-phenylbis(trifluoromethanesulphonimide) (403 g, 1129 mmol) in THF
(3.0 L), under a nitrogen atmosphere, at 25.degree. C. The reaction
was stirred at 25.degree. C. for 20 hours. The reaction was
filtered through a celite pad, washing through with ethyl acetate
(5.0 L). The solvents were removed in vacuo. The crude product was
dissolved in dichloromethane and then chromatographed on silica (5
Kg of Merck lichro prep silica 15-25 .mu.m, 200 mm diameter
column), eluting with a solvent mixture of 40%
ethylacetate/isohexane. Pure fractions were evaporated to dryness
to afford
[4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]trifluoro-
methanesulfonate (406 g, 91%) as a white solid.
[0586] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.62 (3H, s), 2.76
(3H, s), 7.63 (1H, s), 7.77-7.85 (2H, m), 8.09 (1H, d), 8.12 (1H,
s) m/z (ES+) (M+H)+=394
Intermediate 31-7: Methyl
2-[4-[4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-chloroph-
enyl]acetate
##STR00148##
[0588] Dichloro[1,1'-bis(diphenylphosphino)ferrocene]palladium(II)
dichloromethane adduct (68.2 g, 83.5 mmol) was added in one go to a
stirred mixture, which had been degassed for 30 minutes with
nitrogen, of
4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl
trifluoromethanesulfonate (Intermediate 31-6; 730 g, 1856 mmol),
methyl
2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)acetate
(Intermediate 31-3; 1164 g, 1948 mmol) (52% strength by proton
NMR), tripotassium phosphate (690 g, 3248 mmol) and lithium
chloride (138 g, 3248 mmol) in DME (5 L), methanol (2.5 L) and
water (2.5 L) at 20.degree. C. The reaction was heated to reflux
and stirred under a nitrogen atmosphere overnight. The reaction was
cooled to room temperature. The organic layer was filtered through
a glass sinter. Ethyl acetate (10.0 L) and 30% brine/water (5.0 L)
were added. The aqueous layer was separated and extracted with
ethyl acetate (5.0 L), the organic layers were combined, washed
with 50% brine/water (10.0 L), dried (magnesium sulphate), filtered
and the solvents removed in vacuo. The crude product was dissolved
in dichloromethane and then chromatographed on silica (5 Kg of
Merck lichro prep silica 15-25 .mu.m, 200 mm diameter column),
eluting with a solvent gradient of 0-70% ethylacetate/isohexane.
Pure fractions were evaporated to dryness to afford methyl
2-[4-[4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-chloroph-
enyl]acetate (389 g, 49%) as a white solid.
[0589] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.68 (3H, s), 2.79
(3H, s), 3.68 (3H, s), 3.84 (2H, s), 7.39 (1H, d), 7.46 (1H, d),
7.52 (1H, t), 7.58 (1H, s), 7.63 (1H, brs), 7.71 (1H, d), 7.80 (1H,
d), 8.11 (1H, brs)m/z (ES+) (M+H)+=428
Intermediate 31-8: Methyl
2-[4-[4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-chloroph-
enyl]-3-hydroxypropanoate
##STR00149##
[0591] A stirred solution of methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2'-fluorobiphenyl-4-
-yl)acetate (Intermediate 31-7; 615 g, 1437 mmol) in DMF (2.5 L)
was cooled to 15.degree. C., under a nitrogen atmosphere. Potassium
carbonate (214 g, 1545 mmol) was then added followed by
paraformaldehyde (47.5 g, 1581 mmol). The reaction was stirred for
5 hours at 30.degree. C. The reaction was then added to stirred
water (25.0 L) and ethyl acetate (10.0 L). Concentrated
hydrochloric acid (430 ml) was then added slowly with stirring. The
aqueous layer was separated and extracted with ethyl acetate (7.5
L). The organics were combined and washed with, 50% brine/water
(10.0 L), dried (magnesium sulphate), filtered and the solvent was
removed in vacuo. Gave methyl
2-[4-[4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-chlorop-
henyl]-3-hydroxypropanoate (762 g) as a yellow gum, 64% by LCMS
(therefore 488 g, 74% yield). The material was used crude in the
next stage. m/z (ES+) (M+H)+=458, 460
Intermediate 31-9: Methyl
2-[4-[4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-chloroph-
enyl]prop-2-enoate
##STR00150##
[0593] Methanesulfonyl chloride (0.145 L, 1865 mmol) was added over
5 minutes to a stirred solution of methyl
2-(4'-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2'-fluorobiphenyl-4-
-yl)-3-hydroxypropanoate (Intermediate 31-8; 488 g, 1065 mmol) and
triethylamine (0.520 L, 3730 mmol) in tetrahydrofuran (5.0 L) at
10.degree. C. The reaction was heated to 50.degree. C. and left
stirring for 2 hours. The reaction was then cooled to 20.degree. C.
The mixture was diluted with ethyl acetate (10.0 L), then water
(3.0 L) was added. Saturated aqueous ammonium chloride solution
(4.1 L) was added. The organic layer was separated and the aqueous
layer extracted with ethyl acetate (2.5 L). The organics were
combined, washed with 50% brine/water (5.0 L), dried (magnesium
sulphate), filtered and the solvent removed in vacuo. The crude
product was dissolved in dichloromethane and then chromatographed
on silica (5 Kg of Merck lichro prep silica 15-25 .mu.m, 200 mm
diameter column), eluting with a solvent gradient of 0-70%
ethylacetate/isohexane. Pure fractions were evaporated to dryness
to afford methyl
2-[4-[4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-chloroph-
enyl]prop-2-enoate (188 g, 40%) as a white solid.
[0594] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.73 (3H, s), 2.84
(3H, s), 3.86 (3H, s), 6.29 (1H, s), 6.46 (1H, s), 7.55-7.62 (3H,
m), 7.70 (1H, s), 7.76 (1H, d), 7.77-7.80 (1H, m), 7.86-7.90 (1H,
m), 8.18 (1H, s) m/z (ES+) (M+H)+=440, 442
Intermediate 31-10:
2-[4-[4-(6-Carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-chloroph-
enyl]prop-2-enoic acid
##STR00151##
[0596] Potassium hydroxide (flakes) (232 g, 4137 mmol) was added to
a suspension of methyl
2-[4-[4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-chloroph-
enyl]prop-2-enoate (Intermediate 31-9; 364 g, 827 mmol) in
tert-butanol (4.3 L). The reaction was stirred for 4 hours at
30.degree. C. The reaction was poured into stirring saturated
citric acid solution (3.6 L), the resulting suspension (.about.pH
5) was reduced in vacuo until only the aqueous remained. Ethyl
acetate (700 mL) was added and the two phase mixture stirred for 1
hour at 20.degree. C. The white solid was filtered off, washed with
water (2.times.2.5 L) followed by acetonitrile (2.0 L), sucked dry
on the sinter then in a vacuum oven at 65.degree. C. overnight.
Gave
2-[4-[4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-fluorophenyl]-3-chloroph-
enyl]prop-2-enoic acid (265 g, 75%) a yellow solid.
[0597] .sup.1H NMR (400.132 MHz, DMSO) .delta. 2.67 (3H, s), 2.77
(3H, s), 6.12 (1H, s), 6.33 (1H, s), 7.47-7.54 (3H, m), 7.63 (1H,
s), 7.69-7.73 (2H, m), 7.79-7.83 (1H, m), 8.11 (1H, s), COOH not
seen m/z (ES-) (M-H)-=424, 426
* * * * *