U.S. patent application number 13/009773 was filed with the patent office on 2011-05-12 for cysteine protease inhibitors.
This patent application is currently assigned to Medivir AB. Invention is credited to Thierry BONNAUD, Andrew CARR, Bjorn CLASSON, Laia CRESPO, Victor DIAZ, Philip FALLON, Urszula GRABOWSKA, Philip JACKSON, Tony JOHNSON, Jussi KANGASMETSA, Mark LILEY, Magnus NILSSON, Rolf NOREN, Lourdes ODEN, Matt TOZER, Xiao-Xiong ZHOU.
Application Number | 20110112089 13/009773 |
Document ID | / |
Family ID | 34752290 |
Filed Date | 2011-05-12 |
United States Patent
Application |
20110112089 |
Kind Code |
A1 |
NILSSON; Magnus ; et
al. |
May 12, 2011 |
Cysteine Protease Inhibitors
Abstract
A compound of the formula II ##STR00001## wherein one of R.sup.1
and R.sup.2 is halo and the other is H or halo; R.sup.3 is
C.sub.1-C.sub.4 straight or branched chain, optionally fluorinated,
alkyl; R.sup.4 is H; or R.sup.3 together with R.sup.4 and the
adjoining backbone carbon defines: a spiro-C.sub.5-C.sub.7
cycloalkyl, optionally substituted with 1 to 3 substituents
selected from halo, hydroxyl, C.sub.1-C.sub.4 alkyl or
C.sub.1-C.sub.4 haloalkyl; or optionally bridged with a methylene
group; or a C.sub.4-C.sub.6 saturated heterocycle having a hetero
atom selected from O, NRa, S, S(.dbd.O).sub.2; where Ra is H,
C.sub.1-C.sub.4 alkyl or CH.sub.3C(.dbd.O); R.sup.5 is
independently selected from H or methyl; E is --C(.dbd.O)--,
--S(.dbd.O).sub.m--, --NR.sup.5S(.dbd.O).sub.m--,
--NR.sup.5C(.dbd.O)--, --OC(.dbd.O)--, R.sup.6 is a stable,
optionally substituted, monocyclic or bicyclic, carbocycle or
hetorocycle; m is independently 0, 1 or 2; are inhibitors of
cathepsin K and useful in the treatment or prophylaxis of
osteoporosis.
Inventors: |
NILSSON; Magnus; (Huddinge,
SE) ; ZHOU; Xiao-Xiong; (Huddinge, SE) ; ODEN;
Lourdes; (Huddinge, SE) ; CLASSON; Bjorn;
(Huddinge, SE) ; NOREN; Rolf; (Huddinge, SE)
; GRABOWSKA; Urszula; (Essex, GB) ; JACKSON;
Philip; (Little Chesterford, GB) ; FALLON;
Philip; (Little Chesterford, GB) ; CARR; Andrew;
(Little Chesterford, GB) ; LILEY; Mark; (Little
Chesterford, GB) ; TOZER; Matt; (Essex, GB) ;
JOHNSON; Tony; (Essex, GB) ; DIAZ; Victor;
(Essex, GB) ; CRESPO; Laia; (Essex, GB) ;
KANGASMETSA; Jussi; (Essex, GB) ; BONNAUD;
Thierry; (Essex, GB) |
Assignee: |
Medivir AB
Huddinge
SE
|
Family ID: |
34752290 |
Appl. No.: |
13/009773 |
Filed: |
January 19, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10584930 |
Mar 31, 2008 |
7915300 |
|
|
PCT/GB05/50003 |
Jan 6, 2005 |
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13009773 |
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Current U.S.
Class: |
514/233.8 ;
514/254.08; 514/321; 514/338; 514/370; 514/397; 514/412;
514/414 |
Current CPC
Class: |
A61P 25/04 20180101;
A61P 37/00 20180101; A61P 19/08 20180101; A61P 19/10 20180101; A61P
19/02 20180101; A61P 29/00 20180101; C07D 491/04 20130101; A61P
19/00 20180101; A61P 1/02 20180101; A61P 43/00 20180101; A61K
31/407 20130101; A61P 3/14 20180101; A61P 35/00 20180101 |
Class at
Publication: |
514/233.8 ;
514/412; 514/414; 514/370; 514/321; 514/254.08; 514/338;
514/397 |
International
Class: |
A61K 31/5365 20060101
A61K031/5365; A61K 31/407 20060101 A61K031/407; A61K 31/427
20060101 A61K031/427; A61K 31/454 20060101 A61K031/454; A61K 31/497
20060101 A61K031/497; A61K 31/4439 20060101 A61K031/4439; A61K
31/4178 20060101 A61K031/4178; A61P 19/10 20060101 A61P019/10; A61P
35/00 20060101 A61P035/00; A61P 37/00 20060101 A61P037/00; A61P
19/08 20060101 A61P019/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 8, 2004 |
SE |
0400022-0 |
May 26, 2004 |
SE |
0401332-2 |
Claims
1.-28. (canceled)
29. A method of treatment of disorders mediated by cathepsin K
comprising administering to a patient in need of thereof an
effective amount of a compound of formula II ##STR00231## wherein
one of R.sup.1 and R.sup.2 is halo and the other is H or halo;
R.sup.3 is C.sub.1-C.sub.5 straight or branched chain, optionally
fluorinated, alkyl; R.sup.4 is H; or R.sup.3 together with R.sup.4
defines a spiro-C.sub.5-C.sub.7 cycloalkyl, optionally substituted
with 1 to 3 substituents selected from halo, hydroxyl,
C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 haloalkyl; or optionally
bridged with a methylene group: or a C.sub.4-C.sub.6 saturated
heterocycle having a hetero atom selected from O, NRa, S,
S(.dbd.O).sub.2; R.sup.5 is independently selected from H or
methyl; E is --C(.dbd.O)--, --S(.dbd.O).sub.m--,
--NR.sup.5S(.dbd.O).sub.m--, --NR.sup.5C(.dbd.O)--, --OC(.dbd.O)--,
R.sup.6 is a stable, optionally substituted, monocyclic or
bicyclic, carbocycle or hetorocycle wherein the or each ring has 4,
5 or 6 ring atoms and 0 to 3 hetero atoms selected from S, O and N
and wherein the optional substituents comprise 1 to 3 members
selected from R.sub.7; R.sub.7 is independently selected from halo,
oxo, nitrile, nitro, C.sub.1-C.sub.4 alkyl, --XNRaRb,
--XNRbR.sup.9, --NRbC.sub.1-C.sub.4alkylR.sup.9, NH.sub.2CO--,
X--R.sup.9, X--O--R.sup.9, O--X--R.sup.9, X--C(.dbd.O)R.sup.9,
X--(C.dbd.O)NRaR.sup.9, X--NRbC(.dbd.O)R.sup.9,
X--NHSO.sub.mR.sup.9, X--S(.dbd.O).sub.mR.sup.9,
X--C(.dbd.O)OR.sup.9, X--NRbC(.dbd.O)OR.sup.9; R.sub.9 is
independently H, C.sub.1-C.sub.4 alkyl, C.sub.3-C.sub.6 cycloalkyl,
pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl,
piperazinyl, indolinyl, pyranyl, thiopyranyl, furanyl, thienyl,
pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, imidazolyl, pyridinyl,
pyrimidinyl, pyrazinyl, indolyl, phenyl, any of which is optionally
substituted with R.sup.10; R.sub.10 is independently selected from
hydroxy, XR.sup.9, --XNRaRb, --XNRbR.sup.9,
--NRbC.sub.1-C.sub.4alkylR.sup.9, nitro, cyano, carboxy, oxo,
C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4-alkoxy, C.sub.1-C.sub.4
alkanoyl, carbamoyl; X is independently a bond or C.sub.1-C.sub.4
alkyl; Ra is independently H, C.sub.1-C.sub.4 alkyl or
CH.sub.3C(.dbd.O); Rb is independently H, or C.sub.1-C.sub.4 alkyl
m is independently 0, 1 or 2; or a pharmaceutically acceptable salt
or prodrug thereof.
30. The method according to claim 29, wherein the disorder is
selected from the group consisting of: osteoporosis, gingival
diseases such as gingivitis and periodontitis, Paget's disease,
hypercalcaemia of malignancy metabolic bone disease diseases
characterised by excessive cartilege or matrix degradation, such as
osteoarthritis and rheumatoid arthritis. bone cancers including
neoplasia, and pain.
Description
[0001] This application is a Divisional of co-pending application
Ser. No. 10/584,930 filed on Mar. 31, 2008, and for which priority
is claimed under 35 U.S.C. .sctn.120; and this application claims
priority of PCT/GB2005/050003 filed on Jan. 6, 2005 and Swedish
Application Nos.: 0400022-0 filed on Jan. 8, 2004 and 0401332-2
filed on May 26, 2004 under 35 U.S.C. .sctn.119; the entire
contents of each are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] This invention relates to inhibitors of cysteine proteases,
especially those of the papain superfamily. The invention provides
novel compounds useful in the prophylaxis or treatment of disorders
stemming from misbalance of physiological proteases such as
cathepsin K.
DESCRIPTION OF THE RELATED ART
[0003] The papain superfamily of cysteine proteases is widely
distributed in diverse species including mammals, invertebrates,
protozoa, plants and bacteria. A number of mammalian cathepsin
enzymes, including cathepsins B, F, H, K, L, O and S, have been
ascribed to this superfamily, and inappropriate regulation of their
activity has been implicated in a number of metabolic disorders
including arthritis, muscular dystrophy, inflammation,
glomerulonephritis and tumour invasion. Pathogenic cathepsin like
enzymes include the bacterial gingipains, the malarial falcipains
I, II, Ill et seq and cysteine proteases from Pneumocystis carinii,
Trypanosoma cruzei and brucei, Crithidia fusiculata, Schistosoma
spp.
[0004] The inappropriate regulation of cathepsin K has been
implicated in a number of disorders including osteoporosis,
gingival diseases such as gingivitis and periodontitis, Paget's
disease, hypercalcaemia of malignancy and metabolic bone disease.
In view of its elevated levels in chondroclasts of osteoarthritic
synovium, cathepsin K is implicated in diseases characterised by
excessive cartilege or matrix degradation, such as osteoarthritis
and rheumatoid arthritis. Metastatic neoplastic cells typically
express high levels of proteolytic enzymes that degrade the
surrounding matrix and inhibition of cathepsin K may thus assist in
treating neoplasias.
[0005] International patent application no WO02057270 discloses
compounds of the formula I
##STR00002##
where UVWXY broadly corresponds to the P3 and P2 of dipeptide
cysteine protease inhibitors, Z is inter alia O, S, methylene or
--NR--, R.sup.1 is alkyl, alkylaryl etc and P1 and Q1 are each
methylene, optionally substituted with various carbon chains and
cyclic groups. The compounds are alleged to be useful for the
treatment of protozoal infections such as trypanosomes.
[0006] We have now discovered that introduction of a halogen atom
at a particular ring position produces an order of magnitude
increase in potency against cathepsin K.
BRIEF DESCRIPTION OF THE INVENTION
[0007] In accordance with the invention, there is provided
compounds of the formula II:
##STR00003##
wherein one of R.sup.1 and R.sup.2 is halo and the other is H or
halo; R.sup.3 is C.sub.1-C.sub.5 straight or branched chain,
optionally fluorinated, alkyl;
R.sup.4 is H; or
[0008] R.sup.3 together with R.sup.4 and the adjacent backbone
carbon atom defines [0009] a spiro-C.sub.5-C.sub.7 cycloalkyl,
optionally substituted with 1 to 3 substituents selected from halo,
hydroxyl, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 haloalkyl; or
optionally bridged with a methylene group; or [0010] a
C.sub.4-C.sub.6 saturated heterocycle having a hetero atom selected
from O, NRa, S, S(.dbd.O).sub.2; where Ra is H, C.sub.1-C.sub.4
alkyl or CH.sub.3C(.dbd.O)--; R.sup.5 is independently selected
from H or methyl;
E is --C(.dbd.O)--, --S(.dbd.O).sub.m--,
--NR.sup.5S(.dbd.O).sub.m--, --NR.sup.5C(.dbd.O)--,
--OC(.dbd.O)--;
[0011] R.sup.6 is a stable, optionally substituted, monocyclic or
bicyclic, carbocycle or hetorocycle wherein the or each ring has 4,
5 or 6 ring atoms and 0 to 3 hetero atoms selected from S, O and N
and wherein the optional substituents comprise 1 to 3 members
selected from R.sub.7; R.sup.7 is independently selected from halo,
oxo, nitrile, nitro, C.sub.1-C.sub.4 alkyl, --NRa Rb,
--XNRbR.sup.9, --NRbC.sub.1-C.sub.4alkylR.sup.9, NH2CO--,
X--R.sup.9, X--O--R.sup.9, O--X--R.sup.9, X--C(.dbd.O)R.sup.9,
X--(C.dbd.O)NRa R.sup.9, X--NRbC(.dbd.O)R.sup.9,
X--NHSO.sub.mR.sup.9, X--S(.dbd.O).sub.mR.sup.9,
X--C(.dbd.O)OR.sup.9, X--NRbC(.dbd.O)OR.sup.9; R.sup.9 is
independently H, C.sub.1-C.sub.4 alkyl, C.sub.3-C.sub.6 cycloalkyl,
pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl,
piperazinyl, indolinyl, pyranyl, thiopyranyl, furanyl, thienyl,
pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, imidazolyl, pyridinyl,
pyrimidinyl, pyrazinyl, indolyl, phenyl, any of which is optionally
substituted with R.sub.10; R.sub.10 is independently selected from
hydroxy, --X--R.sup.9, --XNRa Rb, --XNRbR.sup.9,
--NRbC.sub.1-C.sub.4alkylR.sup.9, nitro, cyano, carboxy, oxo,
C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4-alkoxy, C.sub.1-C.sub.4
alkanoyl, carbamoyl; X is independently a bond or C.sub.1-C.sub.4
alkyl; Rb is selected from H, C.sub.1-C.sub.4 alkyl m is
independently 0, 1 or 2; and pharmaceutically acceptable salts
thereof.
[0012] Without in any way wishing to be bound by theory, or the
ascription of tentative binding modes for specific variables, P1,
P2 and P3 as used herein are provided for convenience only and have
their conventional meanings and denote those portions of the
inhibitor believed to fill the S1, S2 and S3 subsites respectively
of the enzyme, where S1 is adjacent the cleavage site and S3 remote
from the cleavage site.
[0013] Preferably the stereochemistry of the P1 group is as
depicted in the partial structure below:
##STR00004##
[0014] Preferably the halogen of R.sup.1 and/or R.sup.2 is chlorine
and most preferably fluorine. It is currently preferred that
R.sup.2 is halo, especially fluorine and R.sup.1 is H, but the
invention extends to compounds wherein R.sup.1 is halo, especially
F and R.sup.2 is H or R.sup.1 and R.sup.2 are each F.
[0015] It will be appreciated that the P1 group may exist in
alternative forms, such as
##STR00005##
and the invention extends to all such alternative forms.
[0016] Preferably the stereochemistry of the P2 group corresponds
to an L-amino acid as depicted in the partial structure below:
##STR00006##
but the invention also extends to D-isomers.
[0017] The invention also includes all isomers and enantiomers at
other chiral centres.
[0018] Currently preferred P2 groups include those wherein R.sup.4
is H and wherein R.sup.3 is iso-butyl. A further preferred P2 group
is homo-t-butyl, that is --CH.sub.2C(CH.sub.3).sub.3
[0019] Alternative preferred P2 groups included those wherein
R.sup.3 and R.sup.4 together define spirocycloalkyl, such as
cyclopentyl, cycloheptyl and especially cyclohexyl.
[0020] If a P2 cycloalkyl is substituted, the substitution is
typically para to the linkage to the backbone. Representative
substituents include monofluoro, difluoro, monohydroxy, geminal
hydroxyl & methyl substituents, monomethyl or geminal
methyl.
[0021] Alternative P2 groups include those wherein R.sup.3 and
R.sup.4 together
define a 6 membered, saturated heterocycle, wherein a hetero atom
selected from O, S, S(.dbd.O).sub.2 or NRx where X is H or methyl,
situated at the position corresponding to para or meta to the point
of attachment to the backbone.
[0022] Representative P2 groups in accordance with the two
paragraphs immendiately above include
##STR00007##
[0023] Currently preferred P2 groups include
##STR00008##
[0024] It is currently preferred that R.sup.5 is H.
[0025] Preferred E groups include --S(.dbd.O).sub.m--, especially
--S(.dbd.O).sub.2--, and most preferably --C(.dbd.O)--.
[0026] Typically R.sup.6 is a monocyclic ring with 5 or especially
6 ring atoms, or a bicyclic ring structure comprising a 6 membered
ring fused to a 4, 5 or 6 membered ring.
[0027] Typical R.sup.6 groups include saturated or unsaturated
heterocycles or saturated or unsaturated carbocycles, any of which
are optionally substituted as described above. Illustrative
variants include C.sub.3-8 cycloalkyl, phenyl, benzyl,
tetrahydronaphthyl, indenyl, indanyl, heterocyclyl such as from
azepanyl, azocanyl, pyrrolidinyl, piperidinyl, morpholinyl,
thiomorpholinyl, piperazinyl, indolinyl, pyranyl,
tetrahydropyranyl, tetrahydrothiopyranyl, thiopyranyl, furanyl,
tetrahydrofuranyl, thienyl, pyrrolyl, oxazolyl, isoxazolyl,
thiazolyl, imidazolyl, pyridinyl, pyrimidinyl, pyrazinyl,
pyridazinyl, tetrazolyl, pyrazolyl, indolyl, benzofuranyl,
benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl,
benzisoxazolyl, quinolinyl, tetrahydroquinolinyl, isoquinolinyl,
tetrahydroisoquinolinyl, quinazolinyl, tetrahydroquinazolinyl and
quinoxalinyl, any of which may be substituted as described
above.
[0028] The saturated heterocycle thus includes radicals such as
pyrrolinyl, pyrrolidinyl, pyrazolinyl, pyrazolidinyl, piperidinyl,
morpholinyl, thiomorpholinyl, pyranyl, thiopyranyl, piperazinyl,
indolinyl, azetidinyl, tetrahydropyranyl, tetrahydrothiopyranyl,
tetrahydrofuranyl, hexahydropyrimidinyl, hexahydropyridazinyl,
1,4,5,6-tetrahydropyrimidinylamine, dihydro-oxazolyl,
1,2-thiazinanyl-1,1-dioxide, 1,2,6-thiadiazinanyl-1,1-dioxide,
isothiazolidinyl-1,1-dioxide and imidazolidinyl-2,4-dione, whereas
the unsaturated heterocycle include radicals such as furanyl,
thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl,
isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl,
thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl,
indolizinyl, indolyl, isoindolyl. In each case the heterocycle may
be condensed with a phenyl ring to form a bicyclic ring system.
[0029] Preferred monocyclic R.sup.6 groups include substituted
pyridyl, substituted pyrimidyl, substituted phenyl, particularly
phenyl substituted with a cyclic group such as pyrrolidine-1-yl,
piperidine-1-yl, 4-methylpiperidin-1-yl,
4-(piperidin-3-ylmethyl)-piperidin-1-yl, morpholin-4-yl,
4-methylpiperazin-1-yl, 2-morpholin-4-yl-ethylamino,
2-morpholin-4-yl-ethyloxy, 1-pyrid-2-ylmethylamino, piperazin-1-yl,
piperid-4-yl or N-piperazinyl, N-substituted with Ra or
piperidin-1-yl which is 4--substituted with --NRaRb. A phenyl
R.sup.6 is conveniently substituted at the 3 or 4 position (para or
meta), for example with such a cyclic group.
[0030] Alternative cyclic substituents to a monocyclic R.sup.6
(such as phenyl) include aryl groups such as phenyl or a 5 or 6
membered heteroaryl group such as thiophene, furyl, triazole,
thiazole, diazole, pyrazole or pyrrolidine. Favoured cyclic
substituents in this context include thiazol-2-yl, pyrid-3-yl and
especially pyrid-2-yl, thien-2-yl or thiazol-5-yl. This cyclic
substituent (ie R.sup.7) is typically bonded direct to such R.sup.6
species (ie X is a bond), but may also for example comprise an
amine spacer such as --NH--, --N(Me), --CH.sub.2NH,
--CH.sub.2N(Me)--, a C.sub.1-C.sub.3alkyl spacer such as
--CH.sub.2-- or a C.sub.1-C.sub.3-alkyloxy spacer such as
ethyloxy
[0031] Any of the cyclic substituents to R.sup.6 in the immediately
preceding paragraph may be substituted as described above with
R.sup.10. For example a heterocycle R.sup.7 group such as thiazolyl
can be substituted with C.sub.1-C.sub.4 alkyl such as methyl.
[0032] Preferably, any of the cyclic substituents to R.sup.6 in the
two immediately preceding paragraphs may itself be substituted with
a cyclic group (that is R.sup.7 comprises an R.sup.9 moiety)
typically a saturated heterocyclic group such as piperidine,
piperazine or morpholine, which saturated cyclic group is
optionally substituted, for example with C.sub.1-C.sub.3 alkyl,
fluoro, difluoro, C.sub.1-C.sub.3alkyloxy or
C.sub.1-C.sub.3alkyloxyC.sub.1-C.sub.3alkyl. As provided in the
definition of R.sup.7, this saturated cyclic group (ie R.sup.9) may
be spaced from the R.sup.6 group by X (eg C.sub.1-C.sub.3alkyl),
amine (eg --NH--), amide, sulphonamide etc, but is typically bonded
directly or via methylene.
[0033] Representative R.sup.9 groups in accordance with the
immediately preceding paragraph include heterocycles such as
pyrrolidine-1-yl, piperidine-1-yl, 4-methylpiperidin-1-yl,
4-(piperidin-3-ylmethyl)-piperidin-1-yl, morpholin-4-yl,
4-methylpiperazin-1-yl, 2-morpholin-4-yl-ethylamino,
2-morpholin-4-yl-ethyloxy, 1-pyrid-2-ylmethylamino, piperazin-1-yl,
piperid-4-yl or N-piperazinyl, N-substituted with Ra or
piperidin-1-yl which is 4-substituted with --NRaRb,
[0034] Currently preferred R.sup.9 substituents include
4-substituted piperazin-4-yl, such as 4-methyl-piperazin-4-yl or
4-methyloxyethyl-piperazin-4-yl, piperid-1-ylmethyl which is
optionally 4-substituted with fluoro or difluoro or
morpholinylmethyl.
[0035] Alternative preferred substituents to a monocyclic R.sup.6
(such as phenyl) include --NRaRb, --CH.sub.2NRa Rb, C.sub.1-C.sub.4
straight or branched alkyl or --O--R.sup.9.
[0036] Representative R.sup.6 groups thus include:
##STR00009##
[0037] Further representative R.sup.6 groups include
##STR00010##
especially
##STR00011##
where Rq and Rq' are independently selected from H, C.sub.1-C.sub.4
alkyl or C.sub.1-C.sub.4alkanoyl or together define an unsaturated
5-7 membered ring, such as piperidine, piperazine or morpholine,
which may in turn be substituted with groups corresponding to
R.sup.10, particularly C.sub.1-C.sub.4 alkyl, fluoro or
difluoro.
[0038] Currently preferred R.sup.6 groups include
##STR00012##
[0039] Representative bicyclic groups for R.sup.6 include
naphthylenyl, especially naphthylen-2-yl; benzo[1,3]dioxolyl,
especially benzo[1,3]dioxol-5-yl, benzofuranyl, especially
benzofuran-2-yl, and especially C.sub.1-C.sub.6 alkoxy substituted
benzofuranyl, more especially 5-(2-piperazin-4-carboxylic acid
tert-butyl ester-ethoxy)benzofuran-2-yl,
5-(2-morpholino-4-yl-ethoxy)-benzofuran-2-yl,
5-(2-piperazin-1-yl-ethoxy)benzofuran-2-yl,
5-(2-cyclohexyl-ethoxy)-benzofuran-2-yl; 7-methoxy-benzofuran-2-yl,
5-methoxy-benzofuran-2-yl, 5,6-dimethoxy-benzofuran-2-yl,
especially halogen substituted benzofuranyl, more especially
5-fluoro-benzofuran-2-yl, 5,6-difluoro-benzofuran-2-yl, especially
C.sub.1-C.sub.6alkyl substituted benzofuranyl, most especially
3-methyl-benzofuran-2-yl; benzo[b]thiophenyl, especially
benzo[blthiophen-2-yl; especially C.sub.1-C.sub.6alkoxy substituted
benzo[b]thiopheny], more especially
5,6-dimethoxy-benzo[b]thiophen-2-yl, quinolinyl, especially
quinolin-2-yl, quinolin-3-yl, quinolin-4-yl, quinolin-6-yl, and
quinolin-5-yl; quinoxalinyl, especially quinoxalin-2-yl;
1,8-naphthyridinyl, especially 1,8-naphthyridin-2-yl; indolyl,
especially indol-2-yl, especially indol-6-yl, indol-5-yl,
especially C.sub.1-C.sub.6alkyl substituted indolyl, more
especially N-methylindol-2-yl; furo[3,2-b]pyridinyl, especially
furo[3,2-b]pyridin-2-yl, and C.sub.1-C.sub.6-alkyl substituted
furo[3,2-b]pyridinyl, especially 3-methyl-furo[3,2-blpyridin-2-yl;
thieno[3,2-b]thiophene, especially thieno[3,2-b]thiophene-2-yl,
more especially C.sub.1-C.sub.6alkyl substituted
thieno[3,2-b]thiophene-2-yl, more especially
5-tert-buty]-3-methylthieno[3,2-b]thiophene-2-yl.
[0040] Favoured R.sup.6 groups include bicyclic rings such as
napthyl, quinoloyl, benzofuranyl, benzothienyl, indolyl and
indolinyl, particularly where the linkage is to the 2 position of
the ring. Favoured substituents to a bicyclic R.sup.6 group include
pyrrolidine-1-yl, piperidine-1-yl, 4-methylpiperidin-1-yl,
4-(piperidin-3-ylmethyl)-piperidin-1-yl, morpholin-4-yl,
4-methylpiperazin-1-yl, 2-morpholin-4-yl-ethylamino,
2-morpholin-4-yl-ethyloxy, 1-pyrid-2-ylmethylamino, piperazin-1-yl,
piperid-4-yl or N-piperazinyl, N-substituted with Ra or
piperidin-1-yl which is 4-substituted with --NRaRb. Especially
preferred substituents, particularly in conjunction with
benzofuranyl include 2-morpholin-4-yl-ethyloxy and
N-methyl-piperidin-4-yloxy and those defined below.
[0041] A currently favoured bicyclic R.sup.6 group is optionally
substituted benzothiazol or benzofuryl or benzoxazolyl, including
those wherein the substituent is --OR.sup.9 or --NRbR.sup.9. For
example, favoured R.sup.6 groups include benzofur-2-yl,
unsubstituted or substituted in the 5 position with a saturated
heterocycle such as piperidine, piperazine or morpholine, which is
optionally substituted with C.sub.1-C.sub.3 alkyl and/or spaced
from the benzofuryl by oxy, methyloxy or ethyloxy. Particularly
favoured benzofuryl R.sup.6 groups thus include:
##STR00013##
[0042] Returning to formula II in general:
[0043] X is typically methylene or especially a bond.
[0044] C.sub.1-C.sub.n alkyl, where n is 4, on its own or within
compound expressions such as C.sub.1-C.sub.4 alkoxy, includes
methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl,
t-butyl, cyclopropyl, methylcyclopropyl and the like, extended in a
likewise fashion for other values of n. For example C.sub.5 alkyl
includes homo-t-butyl (--CH.sub.2C(CH.sub.2C(CH.sub.3).sub.3)
[0045] Halogen or halo includes bromo, chloro and especially
fluoro.
[0046] Haloalkyl means an alkyl group as defined above where at
least one carbon atom bears 1 to 3 halogen atoms, preferably
fluorine atoms. Representative haloalkyl group includes
fluoromethyl, difluoromethyl, trifluoromethyl, 2, fluoroethyl,
2,2-difluorethyl, 2,2,2 trifluorethyl and the like.
[0047] The P1 building block employed in the present invention
represent novel compounds and forms an additional aspect of the
invention. Accordingly, this further aspect of the invention
provides compounds of the formula
##STR00014##
where R1 and R2 are as defined above and PG is a nitrogen
protecting group as defined below, especially formyl, acetyl,
benzoyl, pivaloyl, t-butylacetyl, phenylsulfonyl, benzyl, Fmoc,
t-butoxycarbonyl (BOC) and benzyloxycarbonyl (Cbz). This aspect of
the invention further includes the corresponding unprotected amines
(ie PG=H).
[0048] The preferred embodiment of this aspect of the invention
comprises compounds of the formula
##STR00015##
[0049] where PG is as described above.
[0050] The invention further embraces various novel P3 building
blocks as illustrated in the examples below, as the acid or
protected with a carboxy protecting group.
[0051] Favoured compounds of the invention include those
permutations formed by independent selection of a P3, P2 and P1
member from each of Tables A, B and C:
TABLE-US-00001 TABLE A P1 groups ##STR00016## ##STR00017##
##STR00018##
TABLE-US-00002 TABLE B P2 groups ##STR00019## ##STR00020##
##STR00021## ##STR00022##
TABLE-US-00003 TABLE C P3 groups ##STR00023## ##STR00024##
##STR00025## ##STR00026## ##STR00027## ##STR00028## ##STR00029##
##STR00030## ##STR00031## ##STR00032## ##STR00033## ##STR00034##
##STR00035## ##STR00036## ##STR00037## ##STR00038## ##STR00039##
##STR00040## ##STR00041## ##STR00042## ##STR00043## ##STR00044##
##STR00045## ##STR00046## ##STR00047## ##STR00048## ##STR00049##
##STR00050## ##STR00051## ##STR00052## ##STR00053## ##STR00054##
##STR00055## ##STR00056##
[0052] Additional aspects of the invention include a pharmaceutical
composition comprising a compound as defined above and a
pharmaceutically acceptable carrier or diluent therefor.
[0053] A further aspect of the invention is the use of a compound
as defined above in the manufacture of a medicament for the
treatment of disorders mediated by cathepsin K, such as: [0054]
osteoporosis, [0055] gingival diseases such as gingivitis and
periodontitis, [0056] Paget's disease, [0057] hypercalcaemia of
malignancy [0058] metabolic bone disease [0059] diseases
characterised by excessive cartilege or matrix degradation, such as
osteoarthritis and rheumatoid arthritis, [0060] bone cancers
including neoplasia, [0061] pain.
[0062] The compounds of the invention can form salts which form an
additional aspect of the invention. Appropriate pharmaceutically
acceptable salts of the compounds of Formula II include salts of
organic acids, especially carboxylic acids, including but not
limited to acetate, trifluoroacetate, lactate, gluconate, citrate,
tartrate, maleate, malate, pantothenate, isethionate, adipate,
alginate, aspartate, benzoate, butyrate, digluconate,
cyclopentanate, glucoheptanate, glycerophosphate, oxalate,
heptanoate, hexanoate, fumarate, nicotinate, palmoate, pectinate,
3-phenylpropionate, picrate, pivalate, proprionate, tartrate,
lactobionate, pivolate, camphorate, undecanoate and succinate,
organic sulphonic acids such as methanesulphonate,
ethanesulphonate, 2-hydroxyethane sulphonate, camphorsulphonate,
2-napthalenesulphonate, benzenesulphonate,
p-chlorobenzenesulphonate and p-toluenesulphonate; and inorganic
acids such as hydrochloride, hydrobromide, hydroiodide, sulphate,
bisulphate, hemisulphate, thiocyanate, persulphate, phosphoric and
sulphonic acids. The compounds of Formula II may in some cases be
isolated as the hydrate.
[0063] It will be appreciated that the invention extends to
prodrugs, solvates, complexes and other forms releasing a compound
of formula II in vivo.
[0064] While it is possible for the active agent to be administered
alone, it is preferable to present it as part of a pharmaceutical
formulation. Such a formulation will comprise the above defined
active agent together with one or more acceptable
carriers/excipients and optionally other therapeutic ingredients.
The carrier(s) must be acceptable in the sense of being compatible
with the other ingredients of the formulation and not deleterious
to the recipient.
[0065] The formulations include those suitable for rectal, nasal,
topical (including buccal and sublingual), vaginal or parenteral
(including subcutaneous, intramuscular, intravenous and
intradermal) administration, but preferably the formulation is an
orally administered formulation. The formulations may conveniently
be presented in unit dosage form, e.g. tablets and sustained
release capsules, and may be prepared by any methods well known in
the art of pharmacy.
[0066] Such methods include the step of bringing into association
the above defined active agent with the carrier. In general, the
formulations are prepared by uniformly and intimately bringing into
association the active agent with liquid carriers or finely divided
solid carriers or both, and then if necessary shaping the product.
The invention extends to methods for preparing a pharmaceutical
composition comprising bringing a compound of Formula II or its
pharmaceutically acceptable salt in conjunction or association with
a pharmaceutically acceptable carrier or vehicle. If the
manufacture of pharmaceutical formulations involves intimate mixing
of pharmaceutical excipients and the active ingredient in salt
form, then it is often preferred to use excipients which are
non-basic in nature, i.e. either acidic or neutral.
[0067] Formulations for oral administration in the present
invention may be presented as discrete units such as capsules,
cachets or tablets each containing a predetermined amount of the
active agent; as a powder or granules; as a solution or a
suspension of the active agent in an aqueous liquid or a
non-aqueous liquid; or as an oil-in-water liquid emulsion or a
water in oil liquid emulsion and as a bolus etc.
[0068] With regard to compositions for oral administration (e.g.
tablets and capsules), the term suitable carrier includes vehicles
such as common excipients e.g. binding agents, for example syrup,
acacia, gelatin, sorbitol, tragacanth, polyvinylpyrrolidone
(Povidone), methylcellulose, ethylcellulose, sodium
carboxymethylcellulose, hydroxypropylmethylcellulose, sucrose and
starch; fillers and carriers, for example corn starch, gelatin,
lactose, sucrose, microcrystalline cellulose, kaolin, mannitol,
dicalcium phosphate, sodium chloride and alginic acid; and
lubricants such as magnesium stearate, sodium stearate and other
metallic stearates, glycerol stearate stearic acid, silicone fluid,
talc waxes, oils and colloidal silica. Flavouring agents such as
peppermint, oil of wintergreen, cherry flavouring or the like can
also be used. It may be desirable to add a colouring agent to make
the dosage form readily identifiable. Tablets may also be coated by
methods well known in the art.
[0069] A tablet may be made by compression or moulding, optionally
with one or more accessory ingredients. Compressed tablets may be
prepared by compressing in a suitable machine the active agent in a
free flowing form such as a powder or granules, optionally mixed
with a binder, lubricant, inert diluent, preservative,
surface-active or dispersing agent. Moulded tablets may be made by
moulding in a suitable machine a mixture of the powdered compound
moistened with an inert liquid diluent. The tablets may be
optionally be coated or scored and may be formulated so as to
provide slow or controlled release of the active agent.
[0070] Other formulations suitable for oral administration include
lozenges comprising the active agent in a flavoured base, usually
sucrose and acacia or tragacanth; pastilles comprising the active
agent in an inert base such as gelatin and glycerin, or sucrose and
acacia; and mouthwashes comprising the active agent in a suitable
liquid carrier.
[0071] The appropriate dosage for the compounds or formulations of
the invention will depend upon the indication and the patient and
is readily determined by conventional animal trials. Dosages
providing intracellular (for inhibition of physiological proteases
of the papain superamily) concentrations of the order 0.01-100
.mu.M, more preferably 0.01-10 .mu.M, such as 0.1-25 .mu.M are
typically desirable and achievable.
[0072] Compounds of the invention are prepared by a variety of
solution and solid phase chemistries.
[0073] The compounds are typically prepared as building blocks
reflecting the P1, P2 and P3 moieties of the end product inhibitor.
Without in any way wishing to be bound by theory, or the ascription
of tentative binding modes for specific variables, the notional
concepts P1, P2 and P3 as used herein are provided for convenience
only and have substantially their conventional Schlecter &
Berger meanings and denote those portions of the inhibitor believed
to fill the S1, S2, and S3 subsites respectively of the enzyme,
where S1 is adjacent the cleavage site and S3 remote from the
cleavage site. Compounds defined by Formula I are intended to be
within the scope of the invention, regardless of binding mode.
[0074] Broadly speaking the P1 building block will be an
N-protected-6-fluoro-3-oxo-hexahydro-furo[3,2-b]pyrrole, P2 will be
an N-protected amino acid, whereas P3 typically comprises a capping
group such as a substituted, heteroaroyl or aroyl moiety.
[0075] The suitably protected individual building blocks can first
be prepared and subsequently coupled together i.e.
P2+P1.fwdarw.P2-P1. Alternatively, precursors of the building
blocks can be coupled together and modified at a later stage of the
synthesis of the inhibitor sequence. Further building blocks,
precursors of building blocks or prefabricated bigger fragments of
the desired structure, can then be coupled to the growing chain,
e.g. R.sup.3-E-P2*+P1.fwdarw.R.sup.3-E-P2-P1 or
R.sup.3-E*+P2-P1.fwdarw.R.sup.3-E-P2-P1, where * denotes an
activated form.
[0076] Coupling between two amino acids, an amino acid and a
peptide, or two peptide fragments can be carried out using standard
coupling procedures such as the azide method, mixed
carbonic-carboxylic acid anhydride (isobutyl chloroformate) method,
carbodiimide (dicyclohexylcarbodiimide, diisopropylcarbodiimide, or
water-soluble carbodiimide) method, active ester (p-nitrophenyl
ester, N-hydroxysuccinic imido ester) method, Woodward reagent
K-method, carbonyldiimidazole method, phosphorus reagents or
oxidation-reduction methods. Some of these methods (especially the
carbodiimide method) can be enhanced by adding
1-hydroxybenzotriazole or 4-DMAP. These coupling reactions can be
performed in either solution (liquid phase) or solid phase.
[0077] More explicitly, the coupling step involves the dehydrative
coupling of a free carboxyl of one reactant with the free amino
group of the other reactant in the present of a coupling agent to
form a linking amide bond. Descriptions of such coupling agents are
found in general textbooks on peptide chemistry, for example, M.
Bodanszky, "Peptide Chemistry", 2nd rev ed., Springer-Verlag,
Berlin, Germany, (1993) hereafter simply referred to as Bodanszky,
the contents of which are hereby incorporated by reference.
Examples of suitable coupling agents are
N,N'-dicyclohexylcarbodiimide, 1-hydroxybenzotriazole in the
presence of N,N'-dicyclohexylcarbodiimide or N-ethyl-N'-[(3
dimethylamino) propyl]carbodiimide. A practical and useful coupling
agent is the commercially available (benzotriazol-1-yloxy)
tris-(dimethylamino) phosphonium hexafluorophosphate, either by
itself or in the present of 1-hydroxybenzotriazole or 4-DMAP.
Another practical and useful coupling agent is commercially
available 2-(1H-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium
tetrafluoroborate. Still another practical and useful coupling
agent is commercially available 0-(7-azabenzotrizol-1-yl)-N,N,N',
N'-tetramethyluronium hexafluorophosphate.
[0078] The coupling reaction is conducted in an inert solvent, e.g.
dichloromethane, acetonitrile or dimethylformamide. An excess of a
tertiary amine, e.g. diisopropylethylamine, N-methylmorpholine,
N-methylpyrrolidine or 4-DMAP is added to maintain the reaction
mixture at a pH of about 8. The reaction temperature usually ranges
between 0.degree. C. and 50.degree. C. and the reaction time
usually ranges between 15 min and 24 h.
[0079] The functional groups of the constituent non-natural amino
acids generally must be protected during the coupling reactions to
avoid formation of undesired bonds. The protecting groups that can
be used are listed in Greene, "Protective Groups in Organic
Chemistry", John Wiley & Sons, New York (1981) and "The
Peptides: Analysis, Synthesis, Biology", Vol. 3, Academic Press,
New York (1981), hereafter referred to simply as Greene, the
disclosures of which are hereby incorporated by reference.
[0080] The alpha-carboxyl group of the C-terminal residue is
usually protected as an ester that can be cleaved to give the
carboxylic acid. Protecting groups that can be used include 1)
alkyl esters such as methyl, trimethylsilyl and t.butyl, 2) aralkyl
esters such as benzyl and substituted benzyl, or 3) esters that can
be cleaved by mild base or mild reductive means such as
trichloroethyl and phenacyl esters.
[0081] The alpha-amino group of each amino acid to be coupled is
typically N-- protected. Any protecting group known in the art can
be used. Examples of such groups include: 1) acyl groups such as
formyl, trifluoroacetyl, phthalyl, and p-toluenesulfonyl; 2)
aromatic carbamate groups such as benzyloxycarbonyl (Cbz or Z) and
substituted bensyloxycarbonyls, and 9-fluorenylmethyloxycarbonyl
(Fmoc); 3) aliphatic carbamate groups such as tertbutyloxycarbonyl
(Boc), ethoxycarbonyl, diisopropylmethoxycarbonyl, and
allyloxycarbonyl; 4) cyclic alkyl carbamate groups such as
cyclopentyloxycarbonyl and adamantyloxycarbonyl; 5) alkyl groups
such as triphenylmethyl and benzyl; 6) trialkylsilyl such as
trimethylsilyl; and 7) thiol containing groups such
asphenylthiocarbonyl and dithiasuccinoyl. The preferred alpha-amino
protecting group is either Boc or Fmoc. Many amino acid derivatives
suitably protected for peptide synthesis are commercially
available.
[0082] The alpha-amino protecting group is typically cleaved prior
to the next coupling step. When the Boc group is used, the methods
of choice are trifluoroacetic acid, neat or in dichloromethane, or
HCl in dioxane or in ethyl acetate. The resulting ammonium salt is
then neutralized either prior to the coupling or in situ with basic
solutions such as aqueous buffers, or tertiary amines in
dichloromethane or acetonitrile or dimethylformamide. When the Fmoc
group is used, the reagents of choice are piperidine or substituted
piperidine in dimethylformamide, but any secondary amine can be
used. The deprotection is carried out at a temperature between
0.degree. C. and room temperature usually 20-22.degree. C.
[0083] Any of the natural or non-natural amino acids having side
chain functionalities will typically be protected during the
preparation of the peptide using any of the above described groups.
Those skilled in the art will appreciate that the selection and use
of appropriate protecting groups for these side chain
functionalities depend upon the amino acid and presence of other
protecting groups in the peptide. In the selection of such
protecting groups it is desirable that the group is not removed
during the deprotection and coupling of the alpha-amino group.
[0084] For example, when Boc is used as the alpha-amino protecting
group, the following side chain protecting groups are suitable:
p-toluenesulfonyl (tosyl) moieties can be used to protect the amino
side chain of amino acids such as Lys and Arg; acetamidomethyl,
benzyl (Bn), or tert-butylsulfonyl moities can be used to protect
the sulfide containing side chain of cysteine; benzyl (Bn) ethers
can be used to protect the hydroxy containing side chains of
serine, threonine or hydroxyproline; and benzyl esters can be used
to protect the carboxy containing side chains of aspartic acid and
glutamic acid.
[0085] When Fmoc is chosen for the alpha-amine protection, usually
tert. butyl based protecting groups are acceptable. For instance,
Boc can be used for lysine and arginine, tert.butyl ether for
serine, threonine and hydroxyproline, and tert-butyl ester for
aspartic acid and glutamic acid. Triphenylmethyl (Trityl) moiety
can be used to protect the sulfide containing side chain of
cysteine.
[0086] Once the inhibitor sequence is completed any protecting
groups are removed in whatever manner is dictated by the choice of
protecting groups. These procedures are well known to those skilled
in the art.
[0087] The first stage in a synthesis of compounds of the general
formula II is typically the preparation in solution of a
functionalized P1 building block. Different nomenclature of
compounds according to the present invention can be used. For
convenience the carbohydrate nomenclature will generally be used
herein. A typical scheme towards a bicyclic P1 group starts with
the ring closure of a suitably protected intermediate which is
available in 4 steps from
1,2:5,6-di-O-isopropylidene-D-allofuranose, described by Mayer zum
Reckendorf, Chem. Ber. 101 (1968), 3802-3807, giving a precursor of
3S, 4R stereochemistry.
##STR00057##
[0088] In Scheme 1 the azide group of derivative 1 is reduced for
example by catalytic hydrogenation using palladium on charcoal or
other catalysts suitable, in a suitable solvent such as an alcohol,
like ethanol or methanol into the free amine. The obtained
nucleophilic nitrogen reacts spontaneously, or optionally in the
presence of a suitable base like such as triethyl amine or sodium
acetate, with the C-6 position forming a 5,5-bicycle. The leaving
group at C-6 is not limited to sulfonate esters, but also other
leaving groups such as halogen could be used throughout the
synthesis of compounds according to the present invention. The
reduction of the azide residue into an amine could also be
performed by other methods known from literature, such as treating
the azide derivative with a trialkyl- or triarylphosphine followed
by hydrolysis of the formed imine derivative. After the ring
closure the amine may be N-protected with a suitable protecting
group such as a carbamate, like benzyl carbamate of compound 3 or
any other similar protecting group which is normally not cleaved
with acid. Suitable protecting groups which can be found in:
Protective groups in organic chemistry, 3rd edition, 1999, Theodora
W. Greene and Peter G. M. Wuts (Wiley&sons).
[0089] For a 3R, 4S bicycle a similar approach could be used
starting from
3-azido-3-deoxy-1,2:5,6-di-O-isopropylidene-D-gulofuranose which
can be prepared as described in Tetrahedron Asymmetry, 10 (1999)
1855-1859. This intermediate can then be treated as described in
Scheme 2.
##STR00058##
[0090] Compound 4 can be treated with a mild acid, such as diluted
acetic acid or similar, which can selectively hydrolyze the
5,6-acetal of compound 4, to obtain a diol. The primary alcohol can
be selectively reacted with an alkyl- or arylsulfonyl chloride like
p-toluenesulfonyl chloride to give compound 5. The azide group of
derivative 5 is reduced for example by catalytic hydrogenation
using palladium on charcoal or other catalysts suitable, in a
suitable solvent such as an alcohol, like ethanol or methanol into
the free amine. The obtained nucleophilic nitrogen reacts
spontaneously, or optionally in the presence of a suitable base
like such as triethyl amine or sodium acetate, with the C-6
position forming a 5,5-bicycle which can be N-protected with a
suitable protecting group such as its benzyl carbamate (Cbz) to
give compound 6.
[0091] Alternatively
3-azido-3-deoxy-1,2:5,6-di-O-isopropylidene-D-idofuranose (Bull.
Chem. Soc. Japan, 57, 1 (1984), 237-241) could be a suitable
starting material for the 3R, 4S bicycle according to Scheme 3.
##STR00059##
[0092] Compound 6 can be treated with a mild acid, such as diluted
acetic acid or similar, which can selectively hydrolyze the
5,6-acetal of compound 6, to obtain a diol. The primary alcohol can
be selectively reacted with an alkyl- or arylsulfonyl chloride like
p-toluenesulfonyl chloride to give compound 7. The azide group of
derivative 7 is reduced for example by catalytic hydrogenation
using palladium on charcoal or other catalysts suitable, in a
suitable solvent such as an alcohol, like ethanol or methanol into
the free amine. The obtained nucleophilic nitrogen reacts
spontaneously, or optionally in the presence of a suitable base
like such as triethyl amine or sodium acetate, with the C-6
position forming a 5,5-bicycle which can be N-protected with a
suitable protecting group such as its benzyl carbamate (Cbz) to
give compound 8.
[0093] The ring closure is not limited to the substrates shown
above but could also be applied to derivatives as depicted in
Scheme 4.
##STR00060##
[0094] Rx in Scheme 4 may be chosen from methyl, trifluoromethyl,
p-methylphenyl or similar residues present in readily available
alkylsulfonylhalides, preferably a bulky Rx suitable for
regioselective reaction on the primary alcohol of a diol as
described in Chem. Ber. 101 (1968), 3802-3807. R.sup.1' and
R.sup.2' are R.sup.1 and R.sup.2 as defined. Pg could be a suitable
protecting group such as a carbamate, like benzyl carbamate or any
similar protecting group which is not normally cleaved with
acid.
[0095] Further substrates for the ring closure reaction could be
compounds depicted in Scheme 5.
##STR00061##
[0096] Rx in Scheme 5 can be chosen from methyl, trifluoromethyl,
p-methylphenyl or similar residues present in readily available
alkylsulfonylhalides, preferably a bulky Rx suitable for
regioselective reaction on the primary alcohol of a diol as
described in Chem. Ber. 101 (1968), 3802-3807. R.sup.1' and
R.sup.2' are R.sup.1 and R.sup.2 as defined above. Ry can be
hydrogen or a hydroxyl protective group, preferably an ether type
protective group. Preferably Ry is hydrogen. PG could be a suitable
N-protecting group such as a carbamate, for derivatives in Scheme
5, Ry is typically hydrogen.
[0097] Other methodologies to obtain a 5,5-bicycle is disclosed by
G. Lin and Z. Shi, Tetrahedron, 53, 4, 1369-1382, 1997.
[0098] Further modification of the 5,5-bicyclic compound obtained
in scheme 1 is outlined in Scheme 6.
##STR00062##
[0099] Compound 9 is protected with a suitable acid stable
protecting group such as substituted methyl ether, in particular a
benzyl ether, by treating the mono-ol 9 with a base such as sodium
hydride or sodium hydroxide in an aprotic solvent such as
N,N-dimethylformamide (DMF) in the presence of the desired
alkylating agent such as the benzyl halide, in particular benzyl
bromide. The obtained material can then be reduced into compound 10
according to methods described by G. J. Ewing and M. J. Robins,
Org. Lett. 1, 4, 1999, 635-636, or by references therein.
Preferably the reduction is performed with excess boron trifluoride
etherate in the presence of a reducing agent such as
trialkylsilane, in particular with excess triethylsilane in a
suitable non-protic solvent such as dichloromethane. Catalytic
hydrogenation of compound 10 using for example
palladium-on-charcoal in a suitable solvent or solvent mixture such
as ethyl acetate-ethanol in a hydrogen atmosphere, in the presence
of di-tert-butyl dicarbonate followed by treatment of the product
with acetic anhydride in pyridine gives intermediate 11. By
repeated catalytic hydrogenation, as described above, the mono-ol
12 is obtained.
[0100] A fluorine can be introduced on compound 12, and the
bicyclic compound then N-deprotected according to Scheme 7.
##STR00063##
[0101] Compound 13 can be treated with a fluorinating agent such as
[bis-(2-methoxyethyl)aminosulfur trifluoride] (Deoxo-Fluor.RTM.) or
with similar fluorinating agents such as diethylaminosulfur
trifluoride (DAST) which gives the product 14 with inversion of
configuration at C-5. Compound 14 is then deacetylated by treatment
for example with methanolic sodium methoxide, or any similar
alkaline solutions with an inorganic base such as sodium hydroxide
or sodium carbonate, followed by N-deprotection using acidic
conditions such as dichloromethane-trifluoroacetic acid solutions
or other methods which could be found in: Protective Groups in
Organic Chemistry, 3.sup.rd edition, 1999, Theodora W. Greene and
Peter G. M. Wuts (Wiley & Sons).
[0102] Alternatively the epimeric fluorine can be obtained by
treating derivative 9 above according to Scheme 8.
##STR00064##
[0103] Inversion of configuration at C-5 can be accomplished by
reacting compound 16 under Mitsunobo conditions which gives a
benzoate ester. Ester hydrolysis with methanolic sodium methoxide
followed by treatment of the mono-ol with benzyl bromide provides
benzyl protected epimer 17. Reaction steps d-j in Scheme 8 are as
described for Schemes 6 and 7.
[0104] A further route to a "difluoro derivative" wherein R.sup.1
and R.sup.2 are fluoro is shown in Scheme 9.
##STR00065## ##STR00066##
[0105] The synthesis of the P1 building block can be started from
compound 21 (3-azido-3-deoxy-1,2-O-isopropylidene-D-allofuranose)
which is described by Mayer zum Reckendorf, Chem. Ber. 101 (1968),
3802-3807. Treatment of compound 21 with a benzylating agent like
benzyl bromide or benzyl chloride in the presence of a base, such
as sodium hydride or sodium hydroxide in a aprotic polar solvent,
such as N,N-dimethylformamide gives derivative 22. Compound 22 is
then treated with a trialkyl silane, such as triethyl silane, with
an excess of a Lewis acid such as boron trifluoride etherate or
trimethylsilyl trifluoromethanesulfonate, in a aprotic solvent such
as dichloromethane. The resulting azide can then be selectively
reduced by catalytic hydrogenation using for example Palladium on
charcoal in the presence of di-tert-butyl carbonate to obtain
compound 23. Alternatively the azide could be reduced with other
methods known from literature such as triphenylphosphine-water,
followed by protection giving a suitable carbamate. In order to
avoid problems with regioselectivity in the following steps,
compound 23 could be treated with an acylating agent such as an
acyl chloride or acid anhydride, such as benzoyl chloride, in neat
organic base such as pyridine or triethyl amine, or in a mixture of
an aprotic solvent such as dichloromethane and a base to give
compound 24. Catalytic hydrogenation of compound 24 as described
above gives diol 25. Selective benzylation at the primary alcohol
of compound 25 can be accomplished by several methods known from
the literature. In Scheme 9 the diol is refluxed with dibutyl tin
oxide in a suitable solvent such as toluene to form a tin acetal.
The tin acetal can then be reacted with a small excess of benzyl
bromide and cesium fluoride in DMF giving the desired compound 26.
Oxidation of 26 with a suitable oxidizing agent such as Dess-Martin
periodinane in dichloromethane converts the secondary alcohol into
the keto compound 27 suitable to convert into the difluoride 28.
This can be accomplished by treating compound 27 with an excess
fluorinating agent such as Deoxo-Fluor.RTM., or with
diethylaminosulfur trifluoride (DAST), in an aprotic solvent such
as dichloromethane or 1,2-dichloroethane. The benzoate ester of
compound 28 can be cleaved with alkali such as methanolic sodium
methoxide, followed by debenzylation using catalytic hydrogenation
to obtain diol 29. Selective introduction of a sulfonate ester at
the primary alcohol can be accomplished by treating the compound 29
with a small excess of alkyl- or arylsulfonyl chloride in the
presence of a base such as pyridine in suitable solvent such as
dichloromethane, adding the sulfonylating agent at reduced
temperature and slowly increase up to room temperature, which gives
mono-ol 30. Treatment of compound 30 under acidic conditions such
as mixtures of dichlormethane-trifluoroacetic acid liberates the
amine, and treating the product with a base such as triethyl amine
promotes the internal ring closure which gives building block
31.
[0106] Alternative routes to 5,5-bicycles are shown in Schemes 10
and 11.
##STR00067##
[0107] In Scheme 10 a derivative such as compound 32 (available as
described above or with methods well known in the art) with the
substituents at C-3 and C-4 in cis relationship, Lg being a leaving
group such as halogen or a sulfonate ester, and with R equal to an
azide or a nitrogen protected with a suitable N-protecting group,
can be treated with a fluorinating agent such as mentioned above,
producing compound 33. Upon liberating the masked amine with either
reduction of the azide or by a suitable deprotection method, the
amine could perform an intramolecular attack at C-6 producing a
5,5-bicycle with structure 34, which could optionally be
N-protected (Pg=protecting group or hydrogen). Reduction of C-1
with a suitable reducing agent such as described above or with a
similar reducing agent would give building block 35.
[0108] In Scheme 11 an alternative route to a difluoro-5,5-bicycle
is depicted.
##STR00068##
[0109] In Scheme 11 compound 36 (available as described above or
with methods well known in the art) with the substituents at C-3
and C-4 in cis relationship, Lg being a leaving group such as
halogen or a sulfonate ester, and with R equal to an azide or a
nitrogen protected with a suitable protecting group, can be
oxidized with a Swern-type reaction or other suitable methods which
can give compound 37. Treatment of compound 37 according to Scheme
11 with an excess of fluorinating agent such as mentioned above,
gives compound 38. Upon liberating the masked amine of 38 with
either reduction of the azide or by a suitable deprotection method,
the amine could perform an intramolecular attack at C-6 producing a
5,5-bicycle with structure 39, which could optionally be
N-protected (Pg=protecting group or hydrogen). Reduction of C-1
with a suitable reducing agent such as described above or with a
similar reducing agent gives building block 40.
[0110] A convenient route to compounds wherein R1 or R2 is a
halogen such as chloro is depicted in Scheme 12
##STR00069##
[0111] The P1 building block is then elongated with the natural or
non natural P2 amino acid and the P3 group by conventional solution
or solid phase chemistries, such as those outlined or exemplified
below, or disclosed in WO00/69855 or WO02/057270. P2 and P3 groups
are either commercially available as enantiomers or resolvable from
the racemate or obtainable using simple chemical transformations
known to one skilled in the art. For example,
4-(methyl-piperazine-1-yl)-benzoic acid can be obtained using
Buchwald chemistry (S. L. Buchwald & J. P. Wolfe, Journal of
Organic Chemistry, 2000, 65, 1144) and subsequently elaborated.
Other P3 cores such as 4-(1-piperidin-4-yl)-benzoic acid are
prepared from 1-(4-phenyl-piperidine-1-yl)-ethanone using a
Friedel-Crafts acylation reaction and subsequently elaborated using
standard chemical transformations known to one skilled in the art.
Alternatively, other P3 moieties, such as
5-[2-(4-morpholinyl)ethoxy]-2-benzofuran-2-carboxylic acid, are
prepared using Mitsunobu reactions on solid phase as detailed by L.
S. Richter & T. R. Gadek in Tetrahedron Lett., 1994, 35,
4705.
##STR00070##
[0112] Urethane compounds i.e. E is --OC(.dbd.O)-- can be formed
for example by reaction of an R.sub.6 alcohol with the isocyanate
of the P2 amino acid. The isocyanate, or equivalent reactive
intermediate, can be formed by reaction of the amino group of the
P2-amino acid with phosgene, or with dinitrophenylcarbonate in the
presence of a suitable base, e.g. triethylamine. Alternatively they
can be formed by reaction of the amino group of the P2 amino acid
with a suitable chloroformate, e.g. benzylchloroformate.
[0113] Sulphonamide derivatives i.e. E=S(.dbd.O).sub.2-- can be
prepared by reaction of the amino group of the P2 amino acid with a
suitable sulfonyl chloride in a solvent such as dichloromethane in
the presence of a suitable base such as triethylamine or
dimethylaminopyridine.
[0114] Sulphamide derivatives i.e. E=NRaS(.dbd.O).sub.2-- can be
prepared by reacting a suitable R.sub.6 amine in a sulphonyl
chloride solvent followed by reaction of the formed sulfamoyl
chloride derivative with the amino group of the above mentioned
R.sub.4 amino acid in a solvent such as dichloromethane in the
presence of a suitable base such as triethylamine.
[0115] Alternatively the P1 building block as the hydroxyl may be
elongated and subsequently oxidised as shown in Scheme 14 and the
Examples.
##STR00071##
[0116] The term "N-protecting group" or "N-protected" as used
herein refers to those groups intended to protect the N-terminus of
an amino acid or peptide or to protect an amino group against
undesirable reactions during synthetic procedures. Commonly used
N-protecting groups are disclosed in Greene, "Protective Groups in
Organic Synthesis" (John Wiley & Sons, New York, 1981), which
is hereby incorporated by reference. N-protecting groups include
acyl groups such as formyl, acetyl, propionyl, pivaloyl,
t-butylacetyl, 2-chloroacetyl, 2-bromoacetyl, trifluoracetyl,
trichloroacetyl, phthalyl, o-nitrophenoxyacetyl, a-chlorobutyryl,
benzoyl, 4-chlorobenzoyl, 4-bromobenzoyl, 4-nitrobenzoyl, and the
like; sulfonyl groups such as benzenesulfonyl, p-toluenesulfonyl,
and the like, carbamate forming groups such as benzyloxycarbonyl,
p-chlorobenzyloxycarbonyl, p-methoxybenzyloxycarbonyl,
p-nitrobenzyloxycarbonyl, 2-nitrobenzyloxycarbonyl,
p-bromobenzyloxycarbonyl, 3,4-dimethoxybenzyloxycarbonyl,
4-methoxybenzyloxycarbonyl, 2-nitro-4,5-dimethoxybenzyloxycarbonyl,
3,4,5-trimethoxybenzyloxycarbonyl,
1-(p-biphenylyl)-1-methylethoxycarbonyl,
.alpha.,.alpha.-dimethyl-3,5-dimethoxybenzyloxycarbonyl,
benzhydryloxycarbonyl, t-butoxycarbonyl,
diisopropylmethoxycarbonyl, isopropyloxycarbonyl, ethoxycarbonyl,
methoxycarbonyl, allyloxycarbonyl, 2,2,2-trichloroethoxycarbonyl,
phenoxycarbonyl, 4-nitrophenoxycarbonyl,
fluorenyl-9-methoxycarbonyl, cyclopentyloxycarbonyl,
adamantyloxycarbonyl, cyclohexyloxycarbonyl, phenylthiocarbonyl,
and the like; alkyl groups such as benzyl, triphenylmethyl,
benzyloxymethyl and the like; and silyl groups such as
trimethylsilyl and the like. Favoured N-protecting groups include
formyl, acetyl, benzoyl, pivaloyl, t-butylacetyl, phenylsulfonyl,
benzyl, t-butoxycarbonyl (BOC) and benzyloxycarbonyl (Cbz).
[0117] Hydroxy and/or carboxy protecting groups are also
extensively reviewed in Greene ibid and include ethers such as
methyl, substituted methyl ethers such as methoxymethyl,
methylthiomethyl, benzyloxymethyl, t-butoxymethyl,
2-methoxyethoxymethyl and the like, silyl ethers such as
trimethylsilyl (TMS), t-butyldimethylsilyl (TBDMS) tribenzylsilyl,
triphenylsilyl, t-butyldiphenylsilyl triisopropyl silyl and the
like, substituted ethyl ethers such as 1-ethoxymethyl,
1-methyl-1-methoxyethyl, t-butyl, allyl, benzyl, p-methoxybenzyl,
dipehenylmethyl, triphenylmethyl and the like, aralkyl groups such
as trityl, and pixyl (9-hydroxy-9-phenylxanthene derivatives,
especially the chloride). Ester hydroxy protecting groups include
esters such as formate, benzylformate, chloroacetate,
methoxyacetate, phenoxyacetate, pivaloate, adamantoate, mesitoate,
benzoate and the like. Carbonate hydroxy protecting groups include
methyl vinyl, allyl, cinnamyl, benzyl and the like.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0118] Various embodiments of the invention will now be described
by way of illustration only with reference to the following
Examples.
Example 1
Construction of P1 Building Block
Step a)
##STR00072##
[0120] A mixture of 54 (5.2 g, 13.0 mmol), palladium-on-carbon
(10%, Acros, 0.66 g) in methanol was hydrogenated at slight
positive pressure. The hydrogen was changed 3 times over a period
of 1 h, after TLC (petroleum ether-ethyl acetate 7:3 and
dichloromethane-methanol 9:1, staining with ammonium
molybdate-cerium sulfate) indicated complete conversion of the
starting material into a major non-UV active spot which colours
AMC, and some weaker higher moving spots (dichloromethane-methanol
9:1). The reaction mixture was then filtered through Celite and
concentrated which gave crude compound 55.
[0121] To a suspension of the residue in dichloromethane (60 ml)
and pyridine (3.2 ml, 40 mmol) at 0.degree. C. was added
benzylchloroformate (0.93 ml, 6.5 mmol). The reaction mixture was
stirred at room temperature for 2 h after which additional pyridine
(3 ml) and benzylchloroformate (0.8 ml) was added at 0.degree. C.
The reaction mixture was then stirred at room temperature
overnight, then diluted with dichloromethane (100 ml), washed
successively with 1M aq. sulfuric acid (2.times.50 ml) and 1M aq.
sodium hydrogen carbonate (1.times.50 ml), then dried (sodium
sulfate), filtered and concentrated onto silica. Flash
chromatography (diameter: 4 cm, YMC-gel: 50 g, packing eluent:
ethyl acetate in petroleum ether 1:4) of the residue using ethyl
acetate in petroleum ether 1:4 (350 ml), 2:3 (250 ml), 1:1 (250
ml), 3:2 (250 ml) and 3:1 (150 ml) gave compound 56 as a foamy
syrup (2.71 g, 8.1 mmol, 62% over 2 steps) after drying in vacuum
overnight.
[0122] NMR data (400 MHz, CDCl.sub.3): .sup.1H, 1.33, 1.52 (2 s,
6H, C(CH.sub.3).sub.2), 2.34 (2 d, 1H, --OH), 3.04 (m, 1H, H-6a),
3.97 (m, 1H, H-6b), 4.19 (m, 1H, H-5), 4.33 (m, 1H, H-3), 4.68,
4.84 (2 d, 1H, H-2), 4.79 (t, 1H, H-4), 5.08-5.24 (m, 2H,
CH.sub.2Ph), 5.86 (br s, 1H, H-1), 7.30-7.42 (m, 5H, Ar--H).
Step b)
##STR00073##
[0124] To a stirred suspension of sodium hydride (60% in mineral
oil, Aldrich, 0.34 g, 8.4 mmol) and compound 56 (2.17 g, 6.47 mmol)
in dimethylformamide (30 ml) was added benzyl bromide (0.81 mmol,
6.8 mmol) during 5 minutes. After stirring 1 h (TLC: ethyl acetate
in petroleum ether 2:3), methanol (approx 2 ml) was added to
destroy excess reagent, then immediately partitioned between ethyl
acetate (180 ml) and water (150 ml). The organic layer was washed
with water (3.times.100 ml), then dried (sodium sulfate), filtered
and concentrated onto silica. Flash chromatography (diameter: 4 cm,
YMC-gel: 40 g, packing eluent: ethyl acetate in petroleum ether
1:4) of the residue using ethyl acetate in petroleum ether 1:4 (100
ml), 3:7 (250 ml) and 2:3 (250 ml) gave a colourless syrup (2.7 g,
6.35 mmol, 98%) after drying in vacuum overnight.
[0125] NMR data (400 MHz, CDCl.sub.3): .sup.1H, 1.31 (s, 3H,
C(CH.sub.3)(CH.sub.3)), 1.51 (d, 3H, C(CH.sub.3)(CH.sub.3)), 3.29
(m, 1H, H-6a), 3.78-3.96 (m, 2H, H-5 and H-6b), 4.22 (dd, 1H, H-3),
4.64, 4.84 (2 M, 4H, H-2, H-4 and CH.sub.2Ph), 5.07-5.22 (m, 1H,
CH.sub.2Ph), 5.94 (m, 1H, H-1), 7.28-7.39 (m, 10H, Ar--H).
Step c)
##STR00074##
[0127] To a stirred solution of compound 7 (2.635 g, 6.19 mmol) in
dichloromethane (28 ml) and triethyl silane (9.9 ml, 61.9 mmol) at
0.degree. C. was added borontrifluoride etherate (7.9 ml, 61.9
mmol) in one portion. The reaction mixture was then stirred at rt
for 24 h (TLC: petroleum ether-ethyl acetate 4:1 and ethyl
acetate-toluene 3:2), then 1M aq. sodium hydrogen carbonate (40 ml)
and some solid sodium hydrogen carbonate was carefully added until
bubbling stopped. The resulting mixture was partitioned between
dichloromethane (100 ml) and water (100 ml). The organic layer was
washed with 1M aq. sodium hydrogen carbonate (1.times.100 ml) and
brine (1.times.100 ml), then dried (sodium sulfate), filtered and
concentrated onto silica. Flash chromatography (diameter: 4 cm,
YMC-gel: 48 g, packing eluent: ethyl acetate-toluene 3:2) of the
residue using ethyl acetate in toluene 3:2 (750 ml) gave a
colorless hard syrup (1.38 g, 3.74 mmol, 60%) of about 85-90%
purity according to TLC. LR-MS: Calcd for C.sub.21
H.sub.24NO.sub.5: 370.2. Found: 370.0 [M+H].
Step d)
##STR00075##
[0129] A mixture of compound 58 (1.38 g, 3.74 mmol),
palladium-on-carbon (Acros, 10%, 0.12 g) and
di-tert-butyl-dicarbonate (0.82 g, 3.7 mmol) in ethyl acetate (50
ml) was hydrogenated at slight overpressure. The hydrogen was
changed 2 times over a period of 1 h and the reaction was monitored
by LC-MS. After 1 h, additional palladium-on-carbon (0.1 g) was
added and the reaction mixture was treated with hydrogen for 1 more
hour. The reaction mixture was then filtered through Celite and
concentrated. The residue was treated with 2:1 pyridine-acetic
anhydride (18 ml) overnight, and then concentrated. The residue was
redissolved in dichloromethane (60 ml) and was washed successively
with 1M aq. sulfuric acid (2.times.40 ml) and 1M aq. sodium
hydrogen carbonate (1.times.40 ml), and then dried (sodium sulfate)
filtered and concentrated. Flash chromatography (diameter: 3 cm,
YMC-gel: 20 g, packing eluent: ethyl acetate in toluene 1:4) of the
residue (dissolved in toluene-ethyl acetate 4:1) using ethyl
acetate in toluene 1:4 (200 ml) and 1:3 (150 ml) gave a colourless
syrup (1.13 g, 3.0 mmol, 80%) after drying in vacuum overnight.
[0130] NMR data (400 MHz, CDCl.sub.3): .sup.1H, 1.45 (s, 9H,
C(CH.sub.3).sub.3), 2.08 (s, 3H, COCH.sub.3), 3.10 (m, 1H, H-6a),
3.74-3.99 (m, 3H, H-1a, H-5 and H-6b), 4.11 (m, 1H, H-1b),
4.16-4.74 (m, 4H H-3, H-4 and CH.sub.2Ph), 5.31 (m, 1H, H-2),
7.28-7.40 (m, 5H, Ar--H).
Step e)
##STR00076##
[0132] A mixture of compound 60 (1.08 g, 2.86 mmol) and
palladium-on-carbon (10%, 0.15 g) in ethyl acetate (30 ml) was
hydrogenated at slight over pressure for 2 h (TLC: toluene-ethyl
acetate 4:1 and 1:1), then filtered through Celite and
concentrated. The mixture was concentrated from dichloromethane
(3.times.10 ml), then dissolved in dichloromethane and to the
solution was added bis-(2-methoxyethyl)aminosulphur trifluoride
(50% in THF, 2.12 ml, 2 eq.) at 0.degree. C. After stirring at rt
overnight additional bis(2-methoxyethyl)aminosulphur trifluoride
(50% in THF, 2 ml) was added and the reaction mixture was stirred
at rt for another night (TLC: toluene-ethyl acetate 1:1, ninhydrine
staining), then 1M aq. sodium hydrogen carbonate was added
carefully until bubbling stopped. The resulting mixture was diluted
with dichloromethane (50 ml), and the organic layer was washed once
with 1M aq. sodium hydrogen carbonate (40 ml), then dried (sodium
sulfate), filtered and concentrated. Flash chromatography
(diameter: 3 cm, Silica: 25 g, packing eluent: toluene-ethyl
acetate 4:1) of the residue (dissolved in toluene-ethyl acetate
4:1) using toluene-ethyl acetate 4:1 gave compound 62 (0.49 g, 1.7
mmol, 59%) as a colourless syrup after drying in vacuum overnight.
Some starting material and sulphur intermediate could be recovered
from the reaction mixture.
[0133] LR-MS: Calcd for C.sub.9H.sub.13FNO.sub.5: 234.1. Found:
234.0 [M+2H-t-Butyl].
Example 2
Elongation with a Typical P2
Step a)
##STR00077##
[0135] To a solution of compound 62 (0.49 g, 1.7 mmol) in methanol
(9.5 ml) was added 0.5 M methanolic sodium methoxide (1 ml), then
stirred at rt for 30 min (TLC: Toluene-ethyl acetate 3:2,
ninhydrine staining). Methanol washed Dowex W X 8 (50-100 mesh,
H.sup.+-form) was carefully added (pH was monitored by pH-paper)
was added until neutral, then the mixture was filtered and
concentrated. The residue was dissolved in dichloromethane and
trifluoroacetic acid was added at 0.degree. C. The reaction mixture
was then stirred at rt for 55 min (TLC: dichloromethane-methanol
9:1, ninhydrine staining), then concentrated. Column chromatography
(diameter: 2 cm, silica: 15 g, packing eluent:
dichloromethane-methanol 95:5) of the residue (dissolved in
dichloromethane-methanol 95:5) using methanol in dichloromethane
5:95 (150 ml), 7:93 (100 ml) and 1:9 (200 ml) gave a hard syrup
which crystallized upon standing (0.39 g, 1.50 mmol, 88%).
[0136] NMR data (400 MHz, DMSO-d6): .sup.1H, 3.34, 3.44 (2 dd, 1H,
H-6a), 3.60-3.70 (m, 2H, H-1a and H-6b), 3.89 (dd, 1H, H-1b), 4.15
(d, 1H, H-3), 4.51 (br s, 1H, H-2), 4.76 (dd, 1H, H-4), 5.26 (dd,
.sup.2J.sub.H,F=48.3 Hz, H-5).
Step b)
##STR00078##
[0138] To a stirred solution of compound 64 (0.34 g, 1.30 mmol),
N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide hydrochloride (0.28
g, 1.43 mmol), 1-hydroxybenzotriazole hydrate (0.22 g) and
N-(tert-Butoxycarbonyl)-L-leucine monohydrate (0.34 g, 1.37 mmol)
in DMF (10 ml) was added triethylamine (0.54 ml, 3.9 mmol), then
stirred at rt for 24 h. The reaction mixture was the partitioned
between 10% aq. citric acid (30 ml) and ethyl acetate (10 ml). The
water layer was extracted with ethyl acetate (3.times.10 ml), then
the organic layers were combined, and washed successively with
water (1.times.20 ml) and 1M aq. sodium hydrogen carbonate
(3.times.20 ml), then dried (sodium sulfate), filtered and
concentrated onto silica. Flash chromatography with ethyl acetate
in petroleum ether (40-60%, stepwise gradient elution) of the
residue gave 15 (0.35 g, 0.98 mmol, 75%) as a colourless amorphous
solid.
[0139] LR-MS: Calcd for C.sub.13H.sub.22FN.sub.2O.sub.5: 305.1.
Found: 305.1 [M+2H-t-Butyl].
Example 3
Elongation with a Typical P3
##STR00079##
[0141] To a solution of compound 65 (0.11 g, 0.31 mmol) in
dichloromethane (2 ml) at 0.degree. C. was added trifluoroacetic
acid (2 ml), then stirred at rt for 45 min. The reaction mixture
was then concentrated and co-concentrated with toluene. To a
suspension of the residue,
N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide hydrochloride (0.064
g, 0.34 mmol), 1-Hydroxybenzotriazole hydrate (0.051 g) and
benzo[b]furan-2-carboxylic acid (0.052 g, 0.32 mmol) in DMF (3 ml)
was added triethylamine (0.13 ml, 0.9 mmol), then stirred at rt for
24 h. The reaction mixture was then concentrated. The residue was
then partitioned between 10% aq. citric acid (30 ml) and ethyl
acetate (10 ml). The water layer was extracted with ethyl acetate
(2.times.10 ml), then the organic layers were combined, and washed
successively with water (1.times.10 ml) and 1M aq. sodium hydrogen
carbonate (3.times.10 ml), then dried (sodium sulfate), filtered
and concentrated onto silica. Flash chromatography with ethyl
acetate in petroleum ether (50-60%, stepwise gradient elution) of
the residue gave 66 (0.11 g, 0.27 mmol, 89%) as a colourless glassy
solid.
[0142] LR-MS: Calcd for C.sub.21H.sub.26FN.sub.2O.sub.5: 405.2.
Found: 405.1 [M+H].
Example 4
Oxidation to P1 Ketone
##STR00080##
[0144] To a stirred solution of compound 66 (0.10 g, 0.25 mmol) in
dichloromethane (4 ml) at rt was added Dess-Martin periodinane
(0.12 g, 0.28 mmol). After stirring for 90 minutes the reaction
mixture was diluted with dichloromethane (10 ml), washed with 1:1
1M aq. sodium hydrogen carbonate-10% aq. sodiumthiosulfate
(4.times.10 ml), then dried (sodium sulfate), filtered and
concentrated onto silica. Flash chromatography with ethyl acetate
in petroleum ether (50-60%, stepwise gradient elution) of the
residue gave 67 (0.072 g, 0.18 mmol, 71%) as a colourless foam.
Compound 67 is obtained as a mixture of geometrical isomers
(rotamers) and their hydrates.
[0145] LR-MS: Calcd for C.sub.21H.sub.24FN.sub.2O.sub.5: 403.2.
Found: 403.0 [M+H]. A NMR sample of the ketoforms of 67 was
obtained as follows; 5 mg of compound 67 (mixture of geometrical
isomers and hydrate forms with the ratio: hydrate/keto 6:4) was
dissolved in DMSO-d6, then heated up to 100.degree. C. in the NMR
apparatus and then allowed to reach 50.degree. C. upon which NMR
indicated only trace amounts of the hydrate forms and the ratio of
the rotamers were 2:1.
[0146] NMR data (500 MHz, DMSO-d6, 50.degree. C.): .sup.1H,
0.90-1.04 (m, 4.times.CH.sub.3, major and minor forms), 1.39-1.82
(m, 2.times.CH.sub.2CH(CH.sub.3).sub.2 and
2.times.CH.sub.2CH(CH.sub.3).sub.2, major and minor forms), 3.56
(m, H-6a, minor), 3.82 (m, H-6A, major), 3.97-4.25 (m, 4.times.H-1,
major and minor forms and H-6b, minor), 4.37 (dd, H-6b, major),
4.62 (d, H-3, minor), 4.79 (m, H, major), 4.84 (d, H-3, major),
4.94 (m, H-4, major), 5.12 (m, H-4, minor), 5.15-5.34 (m, H-5 major
and H-5 minor, H minor, J.sub.H,F major=49.1 Hz, J.sub.H,F
minor=49.4 Hz), 7.35 (t, 1H, Ar--H), 7.47 (t, 1H, Ar--H), 7.57-7.70
(m, 2H, Ar--H), 7.78 (d, 1H, Ar--H), 8.18 (d, --NH, minor), 8.70
(d, --NH, major).
Example 5
An Alternative P3
Step a)
##STR00081##
[0148] To a solution of compound 55 (0.11 g, 0.32 mmol) in
dichloromethane (2 ml) at 0.degree. C. was added trifluoroacetic
acid (2 ml). After stirring for 45 min at rt (TLC: petroleum
ether-ethyl acetate 1:1 and ethyl acetate-methanol-acetic
acid-water 40:3:3:2), the reaction mixture was concentrated and
co-concentrated from toluene (3.times.5 ml). To a suspension of the
residue, 4-(dimethylamino)benzoic acid (0.055 g, 0.33 mmol),
N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide hydrochloride (0.067
g, 0.35 mmol) and 1-hydroxybenzotriazole hydrate (0.053 g) in DMF
(3 ml) was added triethylamine (0.13 ml, 0.95 mmol), then stirred
at rt overnight (TLC: petroleum ether-ethyl acetate 2:3 and ethyl
acetate-methanol-acetic acid-water 40:3:3:2). The reaction mixture
was then concentrated, partitioned between 8% aq. KH.sub.2PO.sub.4
(30 ml) and ethyl acetate (10 ml). The water layer was extracted
with ethyl acetate (3.times.10 ml), and the combined organic layers
were washed with water (1.times.10 ml) and 1M aq. sodium hydrogen
carbonate (3.times.10 ml), then dried (sodium sulphate), filtered
and concentrated. The residue was redissolved in dichloromethane
and concentrated onto silica. Flash chromatography (diameter: 2 cm,
Silica: 8 g, packing eluent: petroleum ether-ethyl acetate 1:1) of
the residue (stepwise gradient elution, ethyl acetate in petroleum
ether 50-100%) gave a colourless foam (0.10 g, 0.25 mmol, 80%).
[0149] LR-MS: Calcd for C.sub.21H.sub.31FN.sub.3O.sub.4: 408.2.
Found: 408.1 [M+H].
Step b)
##STR00082##
[0151] To a stirred solution of the mono-ol 68 (0.096 g, 0.24 mol)
in dichloromethane at rt was added Dess-Martin periodinane (0.11 g,
0.26 mmol). The reaction mixture turned red and after stirring for
approximately 35 min (TLC: petroleum ether-ethyl acetate 2:3), the
reaction mixture was diluted with dichloromethane (10 ml), washed
with 1:1 1M aq. sodium hydrogen carbonate-10% aq. sodiumthiosulfate
(4.times.10 ml), then dried (sodium sulfate), filtered and
concentrated onto silica. Flash chromatography (diameter: 2 cm,
Silica: 7 g, Packing eluent: petroleum ether-ethyl acetate 1:1) of
the residue (stepwise gradient elution, ethyl acetate in petroleum
ether 50-100%) gave a colourless foam (0.039 g, 0.10 mmol,
41%).
[0152] LR-MS: Calcd for C.sub.21H.sub.27FN.sub.3O.sub.4: 404.2.
Found: 404.1 [M-H].
Example 6
An Alternative P3
Step a)
##STR00083##
[0154] To a solution of compound 55 (0.12 g, 0.32 mmol) in
dichloromethane (2 ml) at 0.degree. C. was added trifluoroacetic
acid (2 ml), then stirred at rt for 45 min. The reaction mixture
was then concentrated and co-concentrated with toluene (3.times.5
ml). To a suspension of the residue,
N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide hydrochloride
(0.068 g, 0.36 mmol), 1-hydroxybenzotriazole hydrate (0.055 g) and
4-phenoxybenzoic acid (0.073 g, 0.34 mmol) in DMF (3 ml) was added
triethylamine (0.14 ml, 0.97 mmol), then stirred at rt for 24 h.
The reaction mixture was then concentrated. The residue was then
partitioned between 10% aq. citric acid (30 ml) and ethyl acetate
(10 ml). The water layer was extracted with ethyl acetate
(2.times.10 ml), then the organic layers were combined, and washed
successively with water (1.times.10 ml) and 1M aq. sodium hydrogen
carbonate (3.times.10 ml), then dried (sodium sulfate), filtered
and concentrated onto silica. Flash chromatography of the residue
with 1:1 ethyl acetate in petroleum ether gave colourless hard
syrup (0.14 g, 0.30 mmol, 91%).
[0155] LR-MS: Calcd for C.sub.25H.sub.30FN.sub.2O.sub.5: 457.2.
Found: 457.2 [M+H].
Step b)
##STR00084##
[0157] To a stirred solution of the mono-ol (0.128 g, 0.28 mmol) in
dichloromethane (4 ml) at rt was added Dess-Martin periodinane
(0.12 g, 0.28 mmol). After stirring for 90 minutes the reaction
mixture was diluted with dichloromethane (10 ml), washed with 1:1
1M aq. sodium hydrogen carbonate-10% aq. sodiumthiosulfate
(4.times.10 ml), then dried (sodium sulfate), filtered and
concentrated onto silica. Flash chromatography with ethyl acetate
in petroleum ether (50-60%, stepwise gradient elution) of the
residue gave 71 (0.072 g, 0.18 mmol, 71%) as a colourless foam.
[0158] LR-MS: Calcd for C.sub.21H.sub.28FN.sub.2O.sub.5: 455.2.
Found: 455.1 [M+H].
Example 7
An Alternative P1 Epimer
##STR00085##
[0159] Step a)
##STR00086##
[0161] To a stirred solution of compound (60) (1.58 g, 4.19 mmol)
in methanol (20 mL) was added a solution of 0.5 M sodium methoxide
in methanol (5 mL) at room temperature, then stirred for 40 min.
The reaction mixture was then neutralized with Dowex 50 WX 8
(H+-form), filtered, added triethylamine until slight alkaline,
then concentrated and concentrated from toluene (2.times.20 mL). To
a stirred solution of the residue and imidazole (0.43 g, 6.28 mmol)
in DMF (10 mL) at 0.degree. C. was added
tert-Butyldimethylchlorosilane (0.76 g, 5.02 mmol), then stirred at
room temperature overnight. The reaction mixture was then diluted
with ethyl acetate (100 mL), washed successively with 10% aq.
citric acid (3.times.50 mL) and 1M aq. sodium hydrogen carbonate
(3.times.50 mL), dried (sodium sulphate), filtered and concentrated
onto silica. Column chromatography (stepwise gradient elution,
ethyl acetate in toluene, 5-20%) of the residue afforded the fully
protected intermediate as a syrup (1.86 g). A mixture of palladium
on charcoal (Aldrich 10%, 0.28 g) and the intermediate obtained
above (1.80 g, 4.00 mmol) in ethyl acetate (40 mL) was hydrogenated
at slight overpressure for 1 h, then filtered through celite and
concentrated. The material crystallized upon drying in vacuum to
afford 72 as needles (1.34 g, 90%).
[0162] NMR data (400 MHz, CDCl.sub.3): .sup.1H, delta 0.14 (m, 6H,
Si(CH.sub.3).sub.2), 0.90 (m, 9H, SiC(CH.sub.3).sub.3), 1.48 (m,
9H, C(CH.sub.3).sub.3), 2.53 (m, 1H, OH), 2.78 (dd, 1H, --H-6A),
3.67-4.05 (m, 3H, H-1A, H-1B and H-6B), 4.05-4.21 (m, 2H, H-3 and
H-5), 4.35-4.50 (2 brs, 1H, H-2), 4.57 (m, 1H, H-4).
Step b)
##STR00087##
[0164] To a stirred solution of (72) (1.068 g, 2.97 mmol), benzoic
acid (0.50 g, 4.46 mmol) and triphenylphosphine (1.17 g, 4.46 mmol)
in THF (15 mL) at 0.degree. C. was added dropwise a solution of
diisopropyl azodicarboxylate (0.88 mL, 4.46 mmol) in THF (5 mL)
during 20 minutes. The reaction mixture was then stirred at room
temperature overnight, then concentrated onto silica. Flash
chromatography of the residue using petroleum ether-ethyl acetate
9:1 as eluent, gave a colorless syrup (1.34 g, 97%).
[0165] NMR data (400 MHz, CDCl3): 1H, delta 0.08-0.21 (m, 6H,
Si(CH.sub.3).sub.2), 0.90 (s, 9H, SiC(CH.sub.3).sub.3), 1.42-1.56
(m, 9H, C(CH.sub.3).sub.3), 3.48 (m, 1H, H-6A), 3.70-4.01 (m, 3H,
H-1A, H-1B, H-6B minor and major), 4.21, 4.30 (2d, 1H, H-3), 4.44,
4.56 (2 brs, 1H, H-2), 4.72 (m, 1H, H-4), 5.34 (d, 1H, H-5), 7.45
(t, 2H, Ar--H), 7.58 (t, 1H, Ar--H), 8.00 (d, 2H, Ar--H).
Step c)
##STR00088##
[0167] To a stirred solution of (73) (1.34 g, 2.89 mmol) in
methanol (6 mL) was added a solution of 0.5 M sodium methoxide in
methanol (6 mL) at room temperature, then stirred for 15 min. The
reaction mixture was then neutralized with Dowex 50 WX 8
(H.sup.+-form) and filtered. The obtained solution was added a
solution obtained similarly as above starting from (II) (0.187 g,
0.40 mmol), then concentrated. Flash chromatography of the residue
using toluene-ethyl acetate 3:2 as eluent gave 74 as a colorless
syrup which crystallized upon drying in vacuum (1.091 g, 92%).
[0168] NMR data (400 MHz, CDCl3): 1H, delta 0.06-0.20 (m, 6H,
Si(CH.sub.3).sub.2), 0.89 (s, 9H, SiC(CH.sub.3).sub.3), 1.42-1.54
(m, 9H, C(CH.sub.3).sub.3), 2.03 (brs, 1H, OH), 3.28 (dd, 1H,
H-6A), 3.53-3.79 (m, 3H, H-1A, H-1B, H-6B), 4.19 and 4.34-4.56 (2
m, 4H, H-2, H-3, H-4 and H-5).
Step d)
##STR00089##
[0170] To a stirred solution of (74) (0.428 g, 1.19 mmol) in
dichloromethane (10 mL) in a Teflon coated flask was added
Deoxofluor (50% in THF, 0.53 mL) at room temperature resulting in a
slight temperature increase. The reaction mixture was stirred at
room temperature for 72 h, then diluted with dichloromethane (20
mL), washed with 1M aq. sodium hydrogen carbonate (2.times.20 mL),
dried (sodium sulphate), filtered and concentrated onto silica.
Flash chromatography of the residue using petroleum ether-ethyl
acetate 9:1 as eluent gave (IV) as a colorless oil (0.118 g,
27%).
[0171] NMR data (400 MHz, CDCl3): 1H, delta 0.08-0.20 (m, 6H,
Si(CH.sub.3).sub.2), 0.89 (s, 9H, SiC(CH.sub.3).sub.3), 1.42-1.53
(m, 9H, C(CH.sub.3).sub.3), 3.26 and 3.36 (2 dd, 1H, H-6A), 3.64
(m, 1H, H-1A), 3.73-4.04 (m, 3H, H-1B, H-6B), 4.20 (dd, 1H, H-3*),
4.40, 4.51 (2 s, 1H, H-2), 4.69 (m, 1H, H-4*) 4.86, 4.98 (2 brs,
1H, H-5). * Could be interchanged.
Step e)
##STR00090##
[0173] To a stirred solution of (75) (0.229 g, 0.63 mmol) in THF (8
mL) was added 1M tetrabutylammonium fluoride in THF (0.70 mL), then
stirred at room temperature for 40 min. The reaction mixture was
then concentrated onto silica. Column chromatography of the residue
using toluene-ethyl acetate 1:1 as eluent gave 75 as a colorless
hard syrup (0.150 g, 96%).
[0174] NMR data (400 MHz, CDCl3): 1H, delta1.46-1.53 (m, 9H,
C(CH.sub.3).sub.3), 2.70 (d, 0.3H, OH-minor), 3.26-3.46 (m, 1.7H,
H-6A and OH-major), 3.75-4.04 (m, 3H, H-1A, H-1B and H-6B), 4.29,
4.34 (2 d, 1H, H-3* minor and major), 4.43, 4.50 (2 brs, 1H, H-2
minor and major), 4.74 (m, 1H, H-4*), 4.89, 5.02 (2 brs, 1H,
H-5).
Step f)
##STR00091##
[0176] To a solution of (75) (0.099 g, 0.40 mmol) in
dichloromethane (2 mL) at 0.degree. C., was added trifluoroacetic
acid (2 mL), then stirred at room temperature for 35 min, then
concentrated and concentrated from toluene (3.times.5 mL). To a
suspension of the residue, 1-hydroxybenzotrazole hydrate (0.067 g,
0.44 mmol), N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide x HCl
(0.084 g, 0.44 mmol) and N-(tert-Butoxycarbonyl)-L-leucine
monohydrate (0.105 g, 0.42 mmol) in DMF (4 mL) was added
triethylamine (0.17 mL, 1.2 mmol), then stirred at room temperature
overnight. The reaction was then concentrated into half the volume,
diluted with ethyl acetate (25 mL), washed successively with 10%
aq. citric acid (3.times.15 mL), and 1M aq. sodium hydrogen
carbonate (3.times.15 mL), dried (sodium sulphate), filtered and
concentrated. Column chromatography of the residue using ethyl
acetate-toluene 3:2 afforded (76) as a colorless hard syrup (0.137
g, 95%).
[0177] NMR data (400 MHz, CDCl3, selected signals): 1H, delta
0.89-1.01 (m, 6H, C(CH).sub.2), 4.98, 5.07 (2 dd, 1H, H-5 major and
H-5 minor).
[0178] LR-MS: Calcd for C.sub.17H.sub.30FN.sub.2O.sub.5: 361.2.
Found: 361.1 [M+H].
Step g)
##STR00092##
[0180] To a solution of (76) (0.137 g, 0.38 mmol) in
dichloromethane at 0.degree. C. was added TFA, then stirred at room
temperature for 30 min, then concentrated and concentrated from
toluene (3.times.5 mL). To a suspension of the residue,
1-hydroxybenzotrazole hydrate (0.064 g, 0.42 mmol),
N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide.times.HCl (0.080 g,
0.42 mmol) and benzo[b]furan-2-carboxylic acid (0.065 g, 0.40 mmol)
in DMF (3 mL) was added triethylamine (0.16 mL, 1.2 mmol), then
stirred at room temperature overnight. The The reaction was then
concentrated into half the volume, diluted with ethyl acetate (25
mL), washed successively with 10% aq. citric acid (3.times.15 mL),
and 1M aq. sodium hydrogen carbonate (3.times.15 mL), dried (sodium
sulphate), filtered and concentrated. Column chromatography of the
residue using ethyl acetate-toluene 3:2 afforded (77) as a
colorless hard syrup (0.148 g, 96%).
[0181] LR-MS: Calcd for C.sub.21H.sub.26FN.sub.2O.sub.5: 405.2.
Found: 405.1 [M+H].
Step h)
##STR00093##
[0183] To a stirred solution of (77) (0.148 g, 0.37 mmol) in
dichloromethane at room temperature was added Dess-Martin
periodinane (0.171 g, 0.40 mmol). After stirring for 2 h, the
reaction mixture was diluted with dichloromethane (20 mL), then
washed with 1:1 1M aq. sodium hydrogen carbonate/10% aq. sodium
thiosulphate (3.times.12 mL), dried (sodium sulphate), filtered and
concentrated. Column chromatography of the residue (stepwise
gradient elution, ethyl acetate in toluene, 40-50%) afforded (VIII)
as a colorless foam (0.105 g, 71%).
[0184] NMR data (100 MHz, CDCl.sub.3, selected signals): .sup.13C,
delta 206.7 and 206.5 (C.dbd.O major and minor).
[0185] LR-MS: Calcd for C.sub.21H.sub.24FN.sub.2O.sub.5: 403.2.
Found: 403.1 [M+H].
Example 8
Additional Cathepsin K Inhibitors
[0186] Compounds 8.1-8.13 & 8.15-8.20 depicted in the table
below were synthesised by successively coupling the N-protected P2
and P3 acids itemised in the table, to the P1 building block of
Example 1 using the solid phase methodology outlined below.
Compound 8.14 was synthesised in solution phase as outlined below.
The construction of P2 and P3 building blocks not readily
accessible from commercial sources appears below.
TABLE-US-00004 TABLE 1 No. Structure P2 P3 building block MS data
8.1 ##STR00094## A Ac.sub.2O 301 [M + H].sup.+ 8.2 ##STR00095## A
##STR00096## 353 [M + H].sup.+ 8.3 ##STR00097## A ##STR00098## 353
[M + H].sup.+ 8.4 ##STR00099## A ##STR00100## 363 [M + H].sup.+ 8.5
##STR00101## A ##STR00102## 383 [M + H].sup.+ 8.6 ##STR00103## A
##STR00104## 402 [M + H].sup.+ 8.7 ##STR00105## A ##STR00106## 405
[M + H].sup.+ 8.8 ##STR00107## A ##STR00108## 416 [M + H].sup.+ 8.9
##STR00109## A ##STR00110## 419 [M + H].sup.+ 8.10 ##STR00111## A
##STR00112## 420 [M + H].sup.+ 8.11 ##STR00113## A ##STR00114## 433
[M + H].sup.+ 8.12 ##STR00115## A ##STR00116## 435 [M + H].sup.+
453 [M + 18].sup.+ 8.13 ##STR00117## A ##STR00118## 464 [M +
H].sup.+ 8.14 ##STR00119## B -- 393 [M + H].sup.+ 8.15 ##STR00120##
A ##STR00121## 542 [M + H].sup.+ 560 [M + 18].sup.+ 8.16
##STR00122## A ##STR00123## 544 [M + H].sup.+ 562 [M + 18].sup.+
8.17 ##STR00124## A ##STR00125## 566 [M + H].sup.+ 584 [M +
18].sup.+ 8.18 ##STR00126## A ##STR00127## 598 [M + H].sup.+ 616 [M
+ 18].sup.+ 8.19 ##STR00128## A ##STR00129## 545 [M + H].sup.+ 563
[M + 18].sup.+ 8.20 ##STR00130## C ##STR00131## 556 [M + H].sup.+
574 [M + 18].sup.+ 8.21 ##STR00132## A ##STR00133## 588 [M +
H].sup.+ 606 [M + 18].sup.+ 8.22 ##STR00134## A ##STR00135## 489 [M
+ 18 - morpholine].sup.+ 471 [M + H - morpholine].sup.+ 8.23
##STR00136## A ##STR00137## 472 [M + H].sup.+ 490 [M + 18].sup.+
8.24 ##STR00138## A ##STR00139## 446 [M + H].sup.+ 464 [M +
18].sup.+ 8.25 ##STR00140## A ##STR00141## 560 [M + 18].sup.+ 473
[M + H - morpholine].sup.+ 8.26 ##STR00142## A ##STR00143## [M +
H].sup.+ 470 [M + 18].sup.+ 488 8.27 ##STR00144## A ##STR00145## [M
+ H].sup.+ 517 [M + 18].sup.+ 488 8.28 ##STR00146## A ##STR00147##
[M + H].sup.+ 455 [M + 18].sup.+ 473 8.29 ##STR00148## A
##STR00149## [M + H].sup.+ 469 [M + 18].sup.+ 487 8.30 ##STR00150##
A ##STR00151## [M + H].sup.+ 469 [M + 18].sup.+ 487 8.31
##STR00152## A ##STR00153## [M + H].sup.+ 457 [M + 18].sup.+ 475
8.32 ##STR00154## A ##STR00155## [M + H].sup.+ 471 [M + 18].sup.+
489 8.33 ##STR00156## A ##STR00157## [M + H].sup.+ 483 [M +
18].sup.+ 501 8.34 ##STR00158## A ##STR00159## [M + H].sup.+ 517 [M
+ 18].sup.+ 535 8.35 ##STR00160## A ##STR00161## [M - H].sup.- 529
[M + 18].sup.+ 549 8.36 ##STR00162## A ##STR00163## [M + H].sup.+
532 [M + 18].sup.+ 550 8.37 ##STR00164## A ##STR00165## [M +
H].sup.+ 546 [M + 18].sup.+ 564 8.38 ##STR00166## A ##STR00167## [M
+ H].sup.+ 504 [M + 18].sup.+ 521 8.39 ##STR00168## A ##STR00169##
[M + H].sup.+ 445 [M + 18].sup.+ 463 8.40 ##STR00170## A
##STR00171## [M + H].sup.+ 503 [M + 18].sup.+ 521 8.41 ##STR00172##
A ##STR00173## [M + H].sup.+ 533 [M + 18].sup.+ 551 8.42
##STR00174## A ##STR00175## [M + H].sup.+ 547 [M + 18].sup.+ 565
8.43 ##STR00176## A ##STR00177## [M + H].sup.+ 532 [M + 18].sup.+
550 8.44 ##STR00178## A ##STR00179## 489 [M + 18 -
morpholine].sup.+ 471 [M + H - morpholine].sup.+ 8.45 ##STR00180##
A ##STR00181## 560 [M + 18].sup.+ 473 [M + H - morpholine].sup.+
8.46 ##STR00182## A ##STR00183## [M + H].sup.+ 533 [M + 18].sup.+
551 8.47 ##STR00184## A ##STR00185## [M + H].sup.+ 531 [M +
18].sup.+ 549 8.48 ##STR00186## A ##STR00187## [M + H].sup.+ 529 [M
+ 18].sup.+ 547 8.49 ##STR00188## A ##STR00189## [M + H].sup.+ 489
[M + 18].sup.+ 507 8.50 ##STR00190## A ##STR00191## [M + H].sup.+
531 [M + 18].sup.+ 549 8.51 ##STR00192## A ##STR00193## [M +
H].sup.+ 475 [M + 18].sup.+ 493 8.52 ##STR00194## A ##STR00195## [M
+ H].sup.+ 565 [M + 18].sup.+ 583 8.53 ##STR00196## A ##STR00197##
[M + H].sup.+ 503 [M + 18].sup.+ 521 8.54 ##STR00198## A
##STR00199## [M + H].sup.+ 544 [M + 18].sup.+ 562 8.55 ##STR00200##
A ##STR00201## [M + H].sup.+ 503 [M + 18].sup.+ 521 8.56
##STR00202## A ##STR00203## NA 8.57 ##STR00204## A ##STR00205## [M
+ H].sup.+ 543 [M + 18].sup.+ 561 8.58 ##STR00206## A ##STR00207##
NA 8.59 ##STR00208## A ##STR00209## [M + H].sup.+ 538 [M +
18].sup.+ 556 8.60 ##STR00210## A ##STR00211## [M + H].sup.+ 529 [M
+ 18].sup.+ 547 8.61 ##STR00212## A ##STR00213## [M + H].sup.+ 501
[M + 18].sup.+ 519 8.62 ##STR00214## A ##STR00215## [M + H].sup.+
515 [M + 18].sup.+ 533 8.63 ##STR00216## A ##STR00217## NA 8.64
##STR00218## A ##STR00219## [M + H].sup.+ 538 [M + 18].sup.+ 556
8.65 ##STR00220## A ##STR00221## [M + H].sup.+ 525 [M + 18].sup.+
543 8.66 ##STR00222## A ##STR00223## NA 8.67 ##STR00224## A
##STR00225## NA
[0187] P2 building blocks
##STR00226##
[0188] Solid phase synthesis of 8.1-8.13 & 8.15-8.67 was
generally carried out using Murphy's linker methodology using known
chemistries as described in WO02/88106. The ketone function of the
FmocNH bicycle was derivatised as an acid labile semicarbazone
which provided a carboxylic acid for attachment to the aminomethyl
functionalised polymer support resin using HBTU, HOBt and NMM.
After Fmoc removal the corresponding P2 Fmoc acid was coupled on
where the symmetric anhydride was preformed. Coupling was first
carried out for 8 h, and then repeated with fresh reagents
overnight. After Fmoc removal the P3 acids were introduced using
standard coupling conditions. Washing, drying and cleavage from the
resin provided the crude desired material which was purified either
by column chromatography or preparative hplc. Compounds which
required modified procedures are described below.
1H-Indole-2-carboxylic acid
[1-(6-fluoro-3-oxo-hexahydrofuro[3,2-b]pyrrole-4-carbonyl)-3-methyl-butyl-
]-amide (Example 8.6)
[0189] To the resin bound H.sub.2N-L-Leu-P1 (150 mg, 0.03 mmol) was
added a solution of indole-2-carboxylic acid (24.2 mg, 0.15 mmol)
in DMF (1.0 mL). A solution of 1,3-diisopropylcarbodiimide (19 mg,
0.15 mmol) and 1-hydroxybenzotriazole hydrate (23 mg, 0.15 mmol) in
DMF (1 mL) was then added. The reaction was agitated overnight and
then washed with DMF (7.times.10 mL), MeOH (5.times.10 mL) and TBME
(5.times.10 mL). After drying under vacuum for 17 h, the product
was cleaved from the resin by suspension in 10 mL of 95:5 TFA:
water for 45 mins. The filtrate was then concentrated under N.sub.2
stream, purified by semi preparative HPLC and then freeze dried to
give the title compound as a white solid. Compounds were
characterised by HPLC, .sup.1H NMR and MS which showed both the
ketone and hydrate forms to be present.
4-Piperidin-4-yl benzoic acid (Example 8.9)
[0190] 4-Phenylpiperidine (10.0 g, 62 mmol) and pyridine (5.74 mL,
71 mmol) were dissolved in DCM (80 mL) and cooled to 0.degree. C. A
solution of acetyl chloride (4.00 mL, 71 mmol) in DCM (20 mL) was
added drop wise to the above solution. The mixture was then stirred
for 2 h at RT and when deemed to be complete by hplc, extracted
with water, dried and concentrated in vacuo to afford a light
yellow oil (10.6 g, 84%) which solidified on standing and was used
without further purification. The yellow oil (10.6 g, 52.2 mmol)
was dissolved in DCM and cooled to -78.degree. C. and treated with
oxalyl chloride (18.3 mL, 209 mmol) drop wise followed by the
addition of aluminium chloride (20.9 g, 157 mmol) in portions. When
the addition was complete, the flask was placed in an ice-salt
bath, and the mixture stirred at -20.degree. C. for 3 h and then at
RT overnight. The mixture was then poured onto ice-water and
extracted with DCM (100 mL.times.3), dried and concentrated in
vacuo. The residue was dissolved in aq. NaOH (2N) and HCl (6N) was
added at 0.degree. C. to acidify the solution to pH 5. The
precipitate (7.9 g) was filtered off and washed with water (200
mL). The residue was then suspended in 6N HCl and heated at reflux
for 18 h. The solvent was evaporated and the residue was
recrystallised from ethanol. Crystals were filtered off and
provided the title compound (5.05 g, 63%).
4-(5-Piperidin-1-ylmethyl-thiophen-2-yl)benzoic acid (Example
8.15)
[0191] 5-Bromo-2-thiophenecarboxaldehyde (10 mmol) and piperidine
(10 mmol) were mixed in THF (10 mL) and dibutyltin dichloride (0.2
mmol) was added. After stirring at RT for 5 minutes, phenylsilane
(11 mmol) was added and the reaction allowed to stir at room
temperature for a further 17 h. The reaction was then concentrated
in vacuo and the residue purified by flash chromatography (silica
gel, DCM) to give 1-(5-bromo-thiophen-2-ylmethyl)-piperidine:
m/z=260, 262 in MS ES+ as a golden oil which was used directly in
the subsequent step. A reaction tube containing a magnetic stirrer
bar was charged with 4-carboxyphenylboronic acid (0.05 mmol), the
thiophene bromide (0.05 mmol), Pd(PPh.sub.3).sub.4 (0.025 mmol),
acetonitrile (2 mL) and 1M Na.sub.2CO.sub.3 (aq) (2 mL). The
reaction tube was then sealed and heated by microwave irradiation
(100 W, 4 mins) to 150.degree. C. and held at that temperature for
10 mins. After being allowed to cool to room temperature the
reaction were acidified to pH 1 with 1M HCl and the resulting
precipitate filtered off. This crude product was then passed
through a silica plug to remove any inorganic species and
concentrated to give a the title compound as a brown powder m/z=304
in MS ES+, which was characterised by hplc and MS and used in the
next step without any further purification.
4-(5-Morpholin-4-ylmethyl-thiophen-2-yl)benzoic acid (Example
8.16)
[0192] To synthesise
4-(5-morpholin-4-ylmethyl-thiophen-2-yl)benzoic acid, the
piperidine was substituted by morpholine in the previous
experimental.
5-[2-(4,4-Difluoro-piperidin-1-yl)-ethoxy]-benzofuran-2-carboxylic
acid (Example 8.17)
[0193] To a solution of 4,4-difluoropiperidine hydrochloride (1 g,
6.3 mmol) in THF (20 mL) was added methylbromoacetate (0.63 mL, 6.6
mmol) and triethylamine (2.65 mL, 19.0 mmol). The reaction was
heated at reflux for 4 h. The reaction was diluted with water (50
mL) and the product extracted with ethyl acetate (3.times.20 mL).
The combined organic fractions were washed with brine, dried over
magnesium sulphate and concentrated in vacuo to yield
(4,4-difluoropiperidin-1-yl)acetic acid methyl ester as a brown oil
(1.17 g, 96%). MS 194 (M+H).sup.+. To a solution of
(4,4-difluoropiperidin-1-yl)acetic acid methyl ester (1.17 g, 6.1
mmol) in THF (15 mL) at 0.degree. C. was added potion wise lithium
aluminium hydride (0.46 g, 12.2 mmol). Once the effervescence had
ceased the reaction was heated at 60.degree. C. for 1.5 h. The
reaction was quenched with water (10 mL) followed by sodium
hydroxide solution (2N, 10 mL) then water (10 mL). The reaction was
filtered and the filtrate extracted with ethyl acetate (3.times.20
mL). The combined organic fractions were washed with brine, dried
over magnesium sulphate and concentrated in vacuo to yield
2-(4,4-difluoropiperidin-1-yl)-ethanol as a brown oil (0.99 g,
99%). MS 166 (M+H).sup.+. To a solution of
diisopropylazodicarboxylate (0.36 mL, 1.82 mmol) in DCM (20 mL) was
added polymer supported triphenylphosphine (728 mg, 2.18 mmol). The
reaction was stirred at RT for 10 min.
5-Hydroxybenzofuran-2-carboxylic acid ethyl ester (0.25 g, 1.21
mmol) and 2-(4,4-difluoropiperidin-1-yl)-ethanol (210 mg, 1.27
mmol) were added and the reaction stirred at RT for 16 h. The
reaction was filtered and the filtrate concentrated in vacuo. The
product was purified on silica eluting with 50% tert-butyl methyl
ether in n-heptane to yield
5-[2-(4,4-difluoropiperidin-1-yl)ethoxy]benzofuran-2-carboxylic
acid ethyl ester as a yellow solid (375 mg, 88%). MS 354
(M+H).sup.+. To a solution of
5-[2-(4,4-difluoropiperidin-1-yl)ethoxy]benzofuran-2-carboxylic
acid ethyl ester (375 mg, 1.06 mmol) in THF (5 mL) and water (1 mL)
was added lithium hydroxide (34 mg, 2.12 mmol). The reaction was
stirred at RT for 16 h. The THF was removed in vacuo and the
remaining aqueous solution dried overnight in a freeze dryer to
yield the crude title compound as a brown solid. MS 326 (M+H, 5.3
min) and used for coupling onto H.sub.2N-Leu-P1 without any further
purification.
5-[2-(4-Trifluoromethyl-piperidin-1-yl)-ethoxy]-benzofuran-2-carboxylic
acid (Example 8.18)
[0194] To a solution of 4-trifluoromethylpiperidine hydrochloride
(1 g, 5.3 mmol) in THF (20 mL) was added methylbromoacetate (0.52
mL, 5.5 mmol) and triethylamine (2.2 mL, 15.8 mmol). The reaction
was heated at reflux for 4 h and then diluted with water (50 mL)
and the product extracted with ethyl acetate (3.times.20 mL). The
combined organic fractions were washed with brine, dried over
magnesium sulphate and concentrated in vacuo to yield
(4-trifluoromethylpiperidin-1-yl)acetic acid methyl ester as a
brown oil (1.19 g, 98%). MS 226 (M+H).sup.+. To a solution of
(4-trifluoromethylpiperidin-1-yl)acetic acid methyl ester (1.19 g,
5.3 mmol) in THF (15 mL) at 0.degree. C. was added portion wise
lithium aluminium hydride (0.4 g, 10.6 mmol). Once the
effervescence had ceased the reaction was heated at 60.degree. C.
for 1.5 h. The reaction was quenched with water (10 mL) followed by
sodium hydroxide solution (2N, 10 mL) then water (10 mL). The
reaction was filtered and the filtrate extracted with ethyl acetate
(3.times.20 mL). The combined organic fractions were washed with
brine, dried over magnesium sulphate and concentrated in vacuo to
yield 2-(4-trifluoromethylpiperidin-1-yl)-ethanol as a brown oil
(1.0 g, 99%). MS 198 (M+H).sup.+. To a solution of
diisopropylazodicarboxylate (0.58 mL, 2.28 mmol) in DCM (20 mL) was
added polymer supported triphenylphosphine (1.14 g, 3.4 mmol). The
reaction was stirred at RT for 10 mins.
5-Hydroxybenzofuran-2-carboxylic acid ethyl ester (0.47 g, 2.3
mmol) and 2-(4-trifluoromethylpiperidin-1-yl)-ethanol (0.45 g, 2.28
mmol) were added and the reaction stirred at RT for 16 h. The
reaction was filtered and the filtrate concentrated in vacuo. The
product was purified on silica eluting with 50% tert-butyl methyl
ether in n-heptane to yield
5-[2-(4-trifluoromethylpiperidin-1-yl)ethoxy]benzofuran-2-carboxylic
acid ethyl ester as a yellow solid (548 mg, 62%). MS 386
(M+H).sup.+. To a solution of
5-[2-(4-trifluoromethylpiperidin-1-yl)ethoxy]benzofuran-2-carboxylic
acid ethyl ester (548 mg, 1.42 mmol) in THF (5 mL) and water (1 mL)
was added lithium hydroxide (45 mg, 2.84 mmol). The reaction was
stirred at RT for 16 h. The THF was removed in vacuo and the
remaining aqueous solution dried overnight in a freeze dryer to
yield the crude title compound as a brown solid. MS 358 (M+H).sup.+
which was used directly for coupling with H.sub.2N-Leu-P1.
4-[2-(4-Methyl-piperazin-1-yl)-thiazol-4-yl]-benzoic acid (Examples
8.19 & 8.20)
[0195] To thiocarbonyldiimidazole (2 g, 11.5 mmol) in THF (30 mL)
at RT was added N-methylpiperazine (1.00 g, 10 mmol) drop wise. The
reaction was stirred at RT for 2 h and then at 55.degree. C. for 1
h. The reaction was cooled to RT and 20 mL of THF was removed in
vacuo. 2M NH.sub.3 (10 mL) in MeOH was added and the reaction
stirred for 15 h. A further 2M NH.sub.3 (10 mL) in MeOH was added
and the reaction maintained at 55.degree. C. for 8 h. A pale yellow
precipitate (1.00 g) was observed and filterered off, dried and
used directly in the next step. The thiourea (0.84 g, 5.2 mmol) was
dissolved in EtOH (30 mL) and 4-(2-bromo-acetyl)-benzoic acid (1.28
g, 5.2 mmol) was added. The reaction was heated at reflux for 3 h.
The reaction was cooled to RT and the solid filtered off. The solid
was washed with Et.sub.2O and dried thoroughly. This procedure
provided the title compound as a pale yellow solid (1.23 g,
77%).
[1-(6-Fluoro-3-oxo-hexahydro-furo[3,2-b]pyrrole-4-carbonyl)-cyclohexyl]-ca-
rbamic acid 9H-fluoren-9-ylmethyl ester (Example 8.20)
[0196] Fmoc-1-amino-1-cyclohexane carboxylic acid (0.300 mg, 0.82
mmol) was dissolved in DCM (8 mL) and DAST (1 mL, 8.2 mmol) was
added. After 1.5 h the starting material was consumed and H.sub.2O
(5 mL) was added drop wise with care. The organic layer was
removed, dried (Na.sub.2SO.sub.4) and concentrated in vacuo to
afford a pale brown solid (0.287 g, 96%). This material was used
crude in the next step. (1-Fluorocarbonyl-cyclohexyl)-carbamic acid
9H-fluoren-9-ylmethyl ester (0.050 g, 0.135 mmol) was dissolved in
DMF (1 mL) and added to H.sub.2N--P1 in DMF (1 mL). NMM (0.027 g,
0.27 mmol) was added and the reaction left overnight. The resin was
filtered off to remove spent reagents and fresh reagents were added
and the reaction repeated for a further 24 h. After washing with
DMF (10 mL.times.10) and DCM (10 mL.times.10) the title compound
(loading equivalent to 50% yield) was obtained bound to resin.
[1-(6-Fluoro-3-oxo-hexahydro-furo[3,2-b]pyrrole-4-carbonyl)-3-methyl-butyl-
]-carbamic acid benzyl ester (Example 8.14)
##STR00227##
[0198] Example 8.14 was prepared in solution rather than on solid
phase.
[0199] 6-Fluoro-3-hydroxy-hexahydro-furo[3,2-b]pyrrole-4-carboxylic
acid tert-butyl ester (0.200 g, 0.81 mmol) was dissolved in DCM (4
mL) at 0.degree. C. and TFA (4 mL) added. After stirring at
0-4.degree. C. for 1 h, the solvent was evaporated in vacuo and the
residue left under high vacuum for 4 h to afford a brown oil. The
residue was dissolved in DMF (5 mL) and WSC.HCl (171 mg, 0.89
mmol), HOBt (137 mg, 1.01 mmol), Cbz-Leu-OH (226 mg, 0.85 mmol) and
Et.sub.3N (337 .mu.l, 2.43 mmol) added. After stirring at room
temperature overnight, the reaction mixture was concentrated in
vacuo, dissolved in EtOAc (10 mL), washed with H.sub.2O (5 mL) and
saturated NaHCO.sub.3 solution (5 mL), dried (Na.sub.2SO.sub.4) and
evaporated in vacuo to afford a colourless oil (242 mg; [m+H].sup.+
395).
[1-(6-Fluoro-3-hydroxy-hexahydro-furo[3,2-b]pyrrole-4-carbonyl)-3-methyl--
butyl]-carbamic acid benzyl ester (242 mg, 0.62 mmol) was dissolved
in dry DCM (8 mL) and Dess-Martin periodinane (261 mg, 0.62 mmol)
added. The reaction immediately turned light brown. After stirring
at room temperature for 2.5 h, the yellow solution was diluted with
DCM (8 mL) and washed with saturated NaHCO.sub.3 solution (5 mL),
dried (Na.sub.2SO.sub.4) and evaporated in vacuo to afford a yellow
residue. Purification by column chromatography (EtOAc: heptane;
1:2) yielded the title compound as a colourless oil, 147 mg;
[M+H].sup.+ 393.
4-Thiocarbamoyl-piperazine-1-carboxylic acid tert-butyl ester
(Example 8.21)
[0200] To a solution of piperazine-1-carboxylic acid tert-butyl
ester (32.2 mmol) in tetrahydrofuran (60 ml) was added
thiocarbonyldiimidazole (37.0 mmol). The reaction was stirred at RT
for 2 h then heated at 55.degree. C. for 1 h. The reaction was
concentrated in vacuo to approximately half the volume and
methanolic ammonia added (7N, 107.4 mmol). The reaction was heated
at 55.degree. C. for 16 h. The reaction was concentrated in vacuo
to approximately half the volume and cooled to 0.degree. C. at
which point the product precipitated from solution. The product was
collected by filtration to yield the title compound as a white
solid (3.3 g). 1H NMR (400 MHz, d.sub.6-DMSO) 1.40 (9H, s), 3.32
(4H, s), 3.71 (4H, s), 7.42 (1H,$).
4-[4-(4-Carboxy-phenyl)-thiazol-2-yl]-piperazine-1-carboxylic acid
tert-butyl ester
[0201] To a suspension of 4-thiocarbamoyl-piperazine-1-carboxylic
acid tert-butyl ester (13.3 mmol) in ethanol (60 ml) was added
4-(2-bromoacetyl)-benzoic acid (13.3 mmol) and 4-methylmorpholine
(13.9 mmol). The reaction was heated at reflux for 2.5 h. The
reaction was concentrated in vacuo and the solid washed with water
(200 ml) to yield the title compound as a white solid (3.9 g).
.sup.1H NMR (400 MHz, CDCl.sub.3) 1.45 (9H, s), 3.58 (8H, m), 4.86
(1H, s), 6.95 (1H,$), 7.97 (2H, d, J 8 Hz), 8.1 (2H, d, J 8
Hz).
4-{2-[4-(2-Methoxy-ethyl)-piperazin-1-yl]thiazol-4-yl}-benzoic
acid
[0202]
4-[4-(4-Carboxy-phenyl)-thiazol-2-yl]-piperazine-1-carboxylic acid
tert-butyl ester (5.0 mmol) was dissolved in hydrochloric acid in
dioxane (4N, 25 ml) and the reaction stirred at RT for 2 h. The
reaction was concentrated in vacuo to yield
4-(2-piperazin-1-yl-thiazol-4-yl)-benzoic acid. Trimethoxyethane
(6.5 mmol) was dissolved in aqueous hydrochloric acid (1N, 10 ml)
and the reaction heated at 50.degree. C. for 1.5 h. The reaction
was allowed to cool to RT and was then added to a suspension of
4-(2-piperazin-1-yl-thiazol-4-yl)-benzoic acid (5.0 mmol) in
acetonitrile (25 ml) and sodium acetate buffer (1N, pH 5.5, 10 ml).
The reaction was stirred at RT for 1.5 h. Sodium cyanoborohydride
(6.5 mol) was added and the reaction stirred at RT for 16 h. The
reaction was concentrated in vacuo and the product purified by
flash chromatography (silica gel, 10% methanol in dichloromethane)
to give the title product as a colourless oil (0.9 g). m/z=348
(100% M+H) in MS ES.sup.+.
4-[1-(5-Bromo-thiophen-2-yl)-ethyl]-morpholine (Example 8.22)
[0203] To a solution of morpholine (1.20 mmol) in titanium (IV)
isopropoxide (1.95 mmol) was added 2-acetyl-5-bromothiophene (1.20
mmol). The reaction was heated in a microwave at 150.degree. C. for
5 minutes. Sodium borohydride (1.95 mmol) was added and the
reaction stirred at RT for 16 h. The reaction was diluted with
sodium hydroxide solution (2N, 10 ml) and the solids formed removed
by filtration. The filtrate was extracted with ethylacetate
(3.times.20 ml), the combined organics were washed with brine and
dried over magnesium sulphate. The product was purified by flash
chromatography (silica gel, 10-20% ethylacetate in iso-hexane) to
give the title product as a brown oil: m/z=276 (100%, M+H), 278
(100%, M+H) in MS ES+.
4-[5-(1-Morpholin-4-yl-ethyl)-thiophen-2-yl]-benzoic acid
[0204] 4-[1-(5-Bromo-thiophen-2-yl)-ethyl]morpholine (0.36 mmol),
4-methoxycarbonylphenylboronic acid (0.43 mmol) and sodium
carbonate (1.09 mmol) were suspended in dioxane:water (2 ml, 2:1).
Nitrogen gas was bubbled through the reaction for 5 minutes then
tetrakis(triphenylphosphine)palladium(0) (0.04 mmol) added. The
reaction was heated in a microwave at 150.degree. C. for 10 min.
The reaction was concentrated in vacuo and the product was purified
by flash chromatography (silica gel, 10% methanol in
dichloromethane) to give the title product as a brown oil: m/z=318
(50% M+H), 231 (100%, M+H-morpholine) in MS ES+.
4-{[(1-Methylimidazol-2-yl)methyl]amino}benzoic acid (Example
8.23)
[0205] 1-Methyl-2-imidazolecarboxaldehyde (5.0 mmol) and
methyl-4-aminobenzoate (5.0 mmol) were mixed in MeOH (7 mL). Acetic
acid (0.3 mL) was added and the mixture stirred for 30 minutes at
room temperature. The reaction mixture was cooled, sodium
cyanoborohydride (5.0 mmol) was added and the reaction allowed to
stir at room temperature for a further 17 h. The reaction mixture
was then concentrated under vacuum and partitioned between H.sub.2O
and EtOAc. The aqueous layer was extracted with EtOAc, and the
combined organic layers were washed with H.sub.2O, brine, dried
over MgSO.sub.4 and the solvent removed under vacuum. The residue
was purified by flash chromatography (silica gel, 5% MeOH in DCM)
to give methyl 4-{[(1-methylimidazol-2-yl)methyl]amino}benzoate:
m/z=246 in MS ES+ as a pale yellow solid which was used directly in
the subsequent step.
[0206] To a solution of methyl ester (2.5 mmol) in 1,4-dioxane (5
mL) was added 1M aqueous KOH solution (5.5 mmol) and the reaction
mixture stirred for 18 h. The reaction mixture was neutralised to
pH 7 with 1M HCl and concentrated by N.sub.2 stream. The product
was resuspended in water and lyophilised to give
4-{[(1-methylimidazol-2-yl)methyl]amino}benzoic acid: m/z 232 in MS
ES+as a white solid which was used directly in the subsequent
step.
4-[5-(1-Morpholin-4-yl-ethyl)-furan-2-yl]-benzoic acid (Example
8.25)
[0207] 2-Acetylfuran (20 mmol) and morpholine (20 mmol) were added
to neat titanium isopropoxide (32 mmol) and the reaction stirred
under N.sub.2 at room temperature for 3 h. Methanol (90 ml) was
then added followed by the careful portionwise addition of
NaBH.sub.4 (32 mmol). After stirring at room temperature for 10
mins, the reaction was quenched by addition of 0.1M NaOH and the
resultant mixture filtered through a celite pad. The filtrate was
extracted twice with DCM, dried over Na.sub.2SO.sub.4 and
concentrated in-vacuo. Flash chromatography of the residue (silica,
5 to 20% EtOAc in Heptane) yielded pure
4-(1-furan-2-yl-ethyl)-morpholine as a golden oil: m/z in MS
ES+=182 [M+H].sup.+, 2.76 mmol, 14% yield.
[0208] 4-(1-furan-2-yl-ethyl)-morpholine (1.1 mmol) was taken up in
DCM (5 ml) and stirred at 0.degree. C. Nitrogen was passed through
the reaction vessel and bubbled out through a Dreschel bottle
containing a saturated aqueous solution of sodium thiosulphate,
whilst bromine (1.54 mmol in 2 ml DCM) was added dropwise. After
addition the reaction was stirred at room temperature for 2 h, then
diluted with more DCM, washed twice with 2M Na.sub.2CO.sub.3
solution, dried over Na.sub.2SO.sub.4 and concentrated in-vacuo.
After purification by flash chromatography (silica, 5 to 10% EtOAc
in hexane), 4-[1-(5-bromo-furan-2-yl)-ethyl]-morpholine was
obtained as a golden oil: m/z in MS ES+=260, 262 [m+H].sup.+, 0.46
mmol, 42% yield.
[0209] 4-[1-(5-bromo-furan-2-yl)-ethyl]-morpholine (0.54 mmol) was
taken up in 7 ml toluene and 4-carboxymethylphenylboronic acid
(0.54 mmol) was added as a solution in 0.7 ml of EtOH. 12 ml of 2M
aqueous Na.sub.2CO.sub.3 solution was added, followed by
Pd(PPh.sub.3).sub.4 (0.054 mmol). Reaction was stirred at
70.degree. C. for 17 h under a nitrogen atmosphere and then cooled
to room temperature and extracted with DCM (.times.2). Combined
organic layers were washed with brine, concentrated in vacuo and
the residue purified by flash chromatography (silica, 20-50% EtOAc
in hexane). This furnished the pure
4[5-(1-Morpholin-4-yl-ethyl)-furan-2-yl]-benzoic acid methyl ester
as a powdery grey solid: m/z in MS ES+=316 [m+H].sup.+, 0.08 mmol,
15% yield.
[0210] This ester (0.08 mmol) was heated to 70.degree. C. in 18%
HCl for 2 h at which point HPLC showed all the starting material to
have been hydrolysed. The reaction was cooled and the product that
precipitated out of solution was collected by filtration as a white
solid and used directly in the next step.
4-(2-Methyl-pyridin-3-yloxy)-benzoic acid (Example 8.26)
[0211] A reaction tube containing a magnetic stirrer bar was
charged with ethyl-4-fluorobenzoate (1 mmol), 2-methyl-3-pyridol
(1.0 mmol), potassium carbonate (1.08 mmol) and DMF (2 ml). The
reaction tube was then sealed and heated by microwave irradiation
(100 W, 4 mins) to 150.degree. C. and held at that temperature for
80 mins. The solution was filtered to remove the insoluble
potassium carbonate and then concentrated in vacuo. The residue was
purified by preparative HPLC and freeze dried to give
4-(2-Methyl-pyridin-3-yloxy)-benzoic acid ethyl ester as a white
solid which was hydrolysed by 6N aqueous HCl solution heated by
microwave irradiation (200 W) for 3 mins at 150.degree. C. The
solution was freeze dried to give to 63 mg of hydrochloride salt of
the title compound as a white powder m/z=229 in MS ES+, which was
characterised by HPLC and MS.
4-[2-(1-Dimethylamino-ethyl)-thiazol-4-yl]-benzoic acid (Example
8.27)
4-{2-[1-(tert-Butoxycarbonyl-methyl-amino)-ethyl]-thiazol-4-yl}-benzoic
acid methyl ester
[0212] Boc-L-N Me-Alanine-OH (1.0 g, 4.92 mmols) was dissolved in
dioxan (10 mls) and to this was added pyridine (0.25 mls),
di-tert-butyl dicarbonate (1.4 g, 6.4 mmols) and ammonium hydrogen
carbonate (0.49 g, 6.2 mmols). After stirring for 18 hours the
crude reaction mixture was concentrated in vacuo and re-suspended
in ethyl acetate. This was washed with 1M KHSO.sub.4 and the
organic layer dried over magnesium sulphate. After concentration, a
clear oil was obtained (0.79 g). This was dissolved in ethylene
glycol dimethyl ether (10 mls) and to this was added Lawesson's
reagent (4.31 mmols, 1.74 g). After stirring at room temperature
for 3 hours the reaction mixture was concentrated in vacuo and the
residue re-suspended in ethyl acetate. This was washed with 1M
Na.sub.2CO.sub.3 and the organic layer dried over magnesium
sulphate. After concentration a yellow oil was obtained. This was
purified by flash chromatography (heptane/ethyl acetate) to give a
white solid (0.73 g). This was dissolved in ethanol (10 mls) and
4-(2-Bromo-acetyl)-benzoic acid methyl ester (3.34 mmols, 0.86 g)
was added. The reaction was heated to 50.degree. C. for one hour.
The crude product was purified by flash chromatography
[0213] (heptane/ethyl acetate) to give a white solid (0.39 g). ESMS
(M+H=377.23).
4-[2-(1-Dimethylamino-ethyl)-thiazol-4-yl]-benzoic acid
[0214]
4-{2-[1-(tert-Butoxycarbonyl-methyl-amino)-ethyl]-thiazol-4-yl}-ben-
zoic acid methyl ester was deprotected with a solution of 4N HCl in
dioxan for 1 h. The solvent was removed in vacuo and the residue
freeze dried to get a white solid which was methylated as followed.
4-[2-(1-Methylamino-ethyl)-thiazol-4-yl]-benzoic acid methyl ester
(0.44 mmol) was stirred for one hour with formaldehyde (1.1
equivalent) in methanol (2 ml) and sodium acetate buffer (1N, pH
5.5, 1 ml). Sodium cyanoborohydride (0.49 mmol) was added and the
reaction stirred at RT for 2 h. The reaction was concentrated in
vacuo and the residue was extracted in EtOAc and washed with a 1M
aqueous solution of sodium carbonate. The organic layer was
concentrated in vacuo and the residue was hydrolysed by 6N aqueous
HCl solution heated by microwave irradiation (200 W) for 3 mins at
150.degree. C. The solution was freeze dried to give to 134 mg of
hydrochloride salt of the title compound as a white powder m/z=277
in MS ES+, which was characterised by HPLC and MS.
E-4-[2-(1H-Imidazol-4-O-vinyl]-benzoic acid (Example 8.28)
[0215] {4-(methoxycarbonyl)benzyl(triphenyl)} phosphonium bromide
on polymer support. Methyl-4-bromomethyl benzoate (26 mmol) were
added to a suspension of 4.4 g of PS-Triphelphosphine resin (Fluka,
3 mmolg.sup.-1) in 40 ml of DMF. The solution was gently stirred at
65.degree. C. for 48 hours. The phosphonium resin was washed with
DMF (4.times.40 ml), DCM (4.times.40 ml) and TBME (2.times.40 ml)
and dried in vacuo for 18 h.
E-4-[2-(1H-Imidazol-4-yl)-vinyl]-benzoic acid
[0216] A reaction tube containing a magnetic stirrer bar was
charged with 1-Methyl-1H-imidazole-2-carbaldehyde (1.5 mmol),
potassium carbonate (2.1 mmol),
{4-(methoxycarbonyl)benzyl(triphenyl)} phosphonium bromide on
polymer support (1.5 mmol) and methanol (4 ml). The reaction tube
was then sealed and heated by microwave irradiation (100 W, 3 mins)
to 150.degree. C. and held at that temperature for 5 mins. The
solution was filtered to remove the insoluble potassium carbonate
and then concentrated in vacuo. The residue was purified by
preparative HPLC and freeze dried to give
E-4-[2-(1-Methyl-1H-imidazol-2-yl)-vinyl]-benzoic acid methyl ester
as a white solid which was hydrolysed by 6N aqueous HCl solution
heated by microwave irradiation (200 W) for 3 mins at 150.degree.
C. The solution was freeze dried to give to 90 mg of hydrochloride
salt of the title compound as a white powder m/z=215 in MS ES+,
which was characterised by HPLC and MS.
E-4-[2-(1-Methyl-1H-imidazol-2-yl)-vinyl]-benzoic acid (Example
8.29)
[0217] Same as example 8.28. 1-Methyl-1H-imidazole-2-carbaldehyde
was used as the aldehyde. The title compound was obtained as a
white powder m/z=229 in MS ES+, which was characterised by HPLC and
MS.
E-4-[2-(3-Methyl-3H-imidazol-4-yl)-vinyl]-benzoic acid (Example
8.30)
[0218] Same as example 8.28. 3-Methyl-3H-imidazole-4-carbaldehyde
was used as the aldehyde. The title compound was obtained as a
white powder m/z=229 in MS ES+, which was characterised by HPLC and
MS.
4-[2-(1H-Imidazol-4-yl)-ethyl]-benzoic acid (Example 8.31)
[0219] E-4-[2-(1-Methyl-1H-imidazol-2-yl)-vinyl]-benzoic acid
methyl ester was hydrogenated using Pd/C (10% of substrate weight),
ammonium formate (5 equivalents) in isopropanol heated by microwave
irradiation (200 W) for 5 mins at 150.degree. C. The solution was
filtered through celite to remove the insoluble catalyst, diluted
with water and freeze-dried to remove the excess of ammonium
formate. The obtained solid was hydrolysed by 6N aqueous HCl
solution heated by microwave irradiation (200 W) for 3 mins at
150.degree. C. The solution was freeze dried to give to the
hydrochloride salt of the title compound as a white powder m/z=217
in MS ES+, which was characterised by HPLC and MS.
4-[2-(1-Methyl-1H-imidazol-2-yl)-ethyl]-benzoic acid (Example
8.32)
[0220] Same as example 8.31.
4-[2-(1-Methyl-1H-imidazol-2-yl)-vinyl]-benzoic acid methyl ester
(Example 8.29) was used as the methyl ester. The title compound was
obtained as a white powder m/z=231 in MS ES+, which was
characterised by HPLC and MS.
Potassium 4-methyl(pyridin-2-yl)aminomethylbenzoate (Example
8.33)
[0221] 2-Methylaminopyridine (1.0 mmol) and methyl-4-formylbenzoate
(1.0 mmol) were mixed in THF (2 mL) and dibutyltin dichloride (0.1
mmol) was added. After stirring at RT for 10 minutes, phenylsilane
(1.1 mmol) was added and the reaction mixture allowed to stir at
room temperature for a further 17 h. The reaction mixture was then
concentrated by N.sub.2 stream and the residue purified by flash
chromatography (silica gel, heptane:EtOAc) to give methyl
4-[methyl(pyridin-2-yl)amino]methylbenzoate: m/z=257 in MS ES+as a
yellow oil which was used directly in the subsequent step.
[0222] To a solution of methyl ester (0.27 mmol) in 1,4-dioxane
(0.6 mL) was added 1M aqueous KOH solution (0.59 mmol) and the
reaction mixture stirred for 18 h. The reaction mixture was
concentrated by N.sub.2 stream, resuspended in water and the
product lyophilised to give potassium
4-methyl(pyridin-2-yl)aminomethyl benzoate: m/z 243 in MS ES+ as an
off-white solid which was used directly in the subsequent step.
Sodium
4-(2-{1(S)-[1(tert-butoxycarbonyl)(methyl)amino]ethyl}-5-methyl-1,3-
-thiazol-4-yl)benzoate (Example 8.34)
[0223] Ethyl 4-propionylbenzoate (2.0 mmol), pyrrolidinone
hydrotribromide (2.1 mmol) and 2-pyrrolidinone (2.2 mmol) were
heated in THF (20 mL) at 50 C for 2.5 h. The mixture was cooled,
filtered, concentrated under vacuum and the residual oil
partitioned between H.sub.2O and MTBE. The aqueous layer was
extracted with MTBE, and the combined organic layers were washed
with saturated aqueous sodium metabisulfite solution, H.sub.2O,
brine, dried over MgSO.sub.4 and the solvent removed under vacuum.
The residue was purified by flash column chromatography (9:1
.sup.iHexane: MTBE) to afford ethyl-4(2'-bromopropionyl)benzoate as
a clear oil.
[0224] Ethyl 4(2'-bromopropionyl)benzoate (0.5 mmol), BOC(Me)Ala
thioamide (0.5 mmol) and NMM (0.5 mmol) were heated in EtOH (2 mL)
at 80 C for 3 h. The mixture was cooled, concentrated by N.sub.2
stream and the crude product partitioned between H.sub.2O and MTBE.
The aqueous layer was extracted with MTBE, and the combined organic
layers were washed twice with 1M KHSO.sub.4, brine, dried over
MgSO.sub.4 and the solvent removed under vacuum to give a yellow
oil. The residue was purified by flash column chromatography (9:1
.sup.iHexane: EtOAc) to afford an intense yellow fraction. On
standing for several hours, this fraction decolorises and ethyl
4-(2-{1(S)-[(tert-butoxycarbonyl)(methyl)amino]ethyl}-5-methyl--
1,3-thiazol-4-yl)benzoate was isolated by flash column
chromatography (9:1 .sup.iHexane: EtOAc) as a clear oil: m/z=405
(MH+) and 349 (M-BOC+) in MS ES+.
[0225] To a solution of ethyl ester (0.24 mmol) in 1,4-dioxane (5
mL) and water (1 mL) was added 1M NaOH (0.53 mL) and the reaction
mixture stirred for 18 h. The reaction mixture was concentrated
under vacuum, the product resuspended in water and lyophilised to
give sodium
4-(2-{1(S)-[(tert-butoxycarbonyl)(methy)amino]ethyl}-5-methyl-1,3-thiazol-
-4-yl)benzoate
[0226] : m/z 377 (MH+) and 321 (M-BOC+) in MS ES+ as a white solid
which was used directly in the subsequent step.
Lithium
4-{2-[1(S)-(dimethylamino)ethyl]-5-methyl-1,3-thiazol-4-yl}benzoat-
e (Example 8.35)
[0227] Ethyl
4-(2-{1(S)-[(tert-butoxycarbonyl)(methy)amino]ethyl}-5-methyl-1,3-thiazol-
-4-yl)benzoate was prepared as described previously.
[0228] To a solution of BOC-protected amine (0.25 mmol) in
1,4-dioxane (3 mL) was added 4M HCl in dioxane (4 mL) and the
reaction mixture stirred for 2 h. The reaction mixture was
concentrated under vacuum to afford a viscous pale yellow oil. The
oil was dissolved in 1:1 H.sub.2O:MeCN and lyophilised to afford
ethyl
4-{2-[1(S)-(methylamino)ethyl]-5-methyl-1,3-thiazol-4-yl}benzoate
hydrochloride salt. A pH 5.5 buffer was prepared by adding AcOH to
1M NaOAc until pH 5.5 was reached. The amine hydrochloride (0.28
mmol) was dissolved in 1:1 buffer:MeOH (4 mL) and formaldehyde (37
weight % in water; 0.31 mmol) was added. The mixture was stirred
for 1 h and then sodium cyanoborohydride (0.31 mmol) was added
portionwise. After 1 h, the reaction mixture was concentrated by
N.sub.2 stream. The residue was partitioned between saturated
aqueous NaHCO.sub.3 and EtOAc. The aqueous layer was extracted with
EtOAc and the combined organic layers were washed with H.sub.2O,
brine, dried over Na.sub.2SO.sub.4 and the solvent removed under
vacuum. The residue was purified by preparative HPLC (0.1% TFA in
H.sub.2O: MeCN). The combined HPLC fractions were partitioned
between saturated aqueous NaHCO.sub.3 and EtOAc. The aqueous layer
was extracted with EtOAc and the combined organic layers were
washed with brine, dried over Na.sub.2SO.sub.4 and the solvent
removed under vacuum. The absence of EtOAc was confirmed by
1H-NMR.
[0229] The ethyl ester (0.19 mmol) was dissolved in 1:1
H.sub.2O:1,4-dioxane (8 mL) and 1M LiOH (0.42 mL) was added and the
reaction mixture stirred for 17 h. The reaction mixture was
adjusted to pH 8 by addition of 1M HCl. The mixture was
concentrated under vacuum, resuspended in 1:1 H.sub.2O:MeCN and
lyophilised to give lithium
4-(2-{1(S)-[(dimethyl)amino]ethyl}-5-methyl-1,3-thiazol-4-yl)benzoate:
m/z 291 (MH+) in MS ES+ as a white solid and was used directly in
the subsequent step.
5-(4-Methyl-morpholin-2-ylmethoxy)-benzofuran-2-carboxylic acid
(Example 8.36)
[0230] Ethyl 5-methoxybenzofuran carboxylate (22.7 mmol) was
dissolved in dichloromethane (20 ml) and a 1.0 M solution of boron
tribromide methyl sulphide complex in dichloromethane (68.1 mmol)
was added. The mixture was heated at reflux over night. The solvent
was evaporated under vacuo and the residue purified by flash
chromatography to obtain ethyl 5-hydroxybenzofuran carboxylate as a
white solid. Triphenyl phosphine polymer bound (8.96 mmol) was
suspended in anhydrous dichloromethane (20 ml) then diisopropyl
azodicarboxylate (7.76 mmol) was added and the mixture was stirred
for 15 minutes at room temperature. Then ethyl 5-hydroxybenzofuran
carboxylate (5.97 mmol) was added over 5 minutes followed by the
addition of 4-N-boc-3-morpholinecarboxylic acid (5.97 mmol) over 5
minutes too. The mixture was stirred at room temperature over
night. The solvent was evaporated under vacuo and the residue
purified by flash chromatography to obtain ethyl
5-(4-Boc-morpholin-2-ylmethoxy)-benzofuran-2-carboxylate: m/z=406
in MS ES+, as clear oil. Ethyl
5-(4-Boc-morpholin-2-ylmethoxy)-benzofuran-2-carboxylate (2.47
mmol) was dissolved in 30 ml of a 4.0 M solution of hydrochloric
acid in dioxan and stirred at room temperature for 1 hour. After
removing the solvent under vacuo the resulting amine was dissolved
in anhydrous dichloromethane and N-methylmorpholine (5.67 mmol) was
added and stirred at room temperature for 5 minutes. Then
allylchloroformate (2.71 mmol) was added and the mixture was
stirred at room temperature over night under an inert atmosphere.
The mixture was washed with a 1.0 M solution of hydrochloric acid,
water, dried over Na.sub.2SO.sub.4 and the solvent was evaporated
in vacuo. The residue was purified by flash chromatography to yield
ethyl 5-(4-alloc-morpholin-2-ylmethoxy)-benzofuran-2-carboxylate:
m/z=390 in MS ES+, as a white solid.
[0231] Ethyl
5-(4-alloc-morpholin-2-ylmethoxy)-benzofuran-2-carboxylate (2.09
mmol) was dissolved in 3 ml of tetrahydrofuran. Then 3 ml of a 1.0
M solution of lithium hydroxide were added and the mixture stirred
at room temperature over night. After removing the tetrahydrofuran
under vacuo the mixture was acidified with a 1M solution of
hydrochloric acid to Congo red, extracted with dichloromethane,
washed with water, dried over Na.sub.2SO.sub.4 and the solvent was
removed under vacuo to yield
5-(4-alloc-morpholin-2-ylmethoxy)-benzofuran-2-carboxylic acid as a
white solid.
5-(4-Alloc-morpholin-2-ylmethoxy)-benzofuran-2-carboxylic acid (3
equiv) was then incorporated on the peptide as described previously
(600 mg; 0.32 mmol/g) with HBTU (3 equiv), HOBt (3 equiv) and NMM
(6 equiv) in DMF over night at room temperature. The Alloc group
was removed with (1) DCM (4.times.1 min); (2) borane dimethylamine
complex (40 equiv), tetrakis (triphenylphosphine) palladium (0)
(0.1 equiv) in anhydrous DCM (2.times.15 min); (3) DCM (3.times.1
min); (4) DMF (3.times.1 min); (5) dioxan-water (9:1) (3.times.1
min); (6) DMF (3.times.1 min); (7) MeOH (3.times.1 min); (8) DCM
(3.times.1 min) and the peptide resin was treated with dibutyltin
dichloride (5 equiv), phenylsilane (5 equiv) and a 37% solution of
formaldehyde in water (5 equiv) in THF for 2 hours at room
temperature. The reminder of the procedure was carried out as
described in the general protocol.
3-Methyl-5-(4-methyl-morpholin-2-ylmethoxy)-benzofuran-2-carboxylic
acid (Example 8.37)
[0232] 4-Methoxyphenol (0.119 mol) was dissolved in dry toluene and
treated with sodium hydride (0.120 mol) at room temperature for 60
h. The sodium phenolate solution was heated to +100.degree. C. and
a-chloroacetoacetate (0.09 mol) was added. After stirring at
+110.degree. C. for a further 4 hours, the mixture was cool to room
temperature, washed with water and brine, dried over
Na.sub.2SO.sub.4 and the solvent was evaporated in vacuo to yield a
crude .alpha.-(4-methoxyphenoxy)acetoacetate as a dark brown oil.
Phosphoric acid (0.22 mol) was mixed with P.sub.2O.sub.5 (0.35 mol)
at room temperature and stirred at +130.degree. C. for 4 hours. The
mixture was allowed to cool to +100.degree. C., the acetoacetate
was slowly added, and held at that temperature for 2 hours. After
cooling to room temperature, ice was carefully added to the stirred
solution, extracted with toluene, concentrated in vacuo and
purified by flash chromatography on silica to yield ethyl
3-methyl-5-methoxybenzofuran carboxylate: m/z=235 in MS ES+, as a
white solid.
[0233] Ethyl 3-methyl-5-methoxybenzofuran carboxylate (8.53 mmol)
was dissolved in dichloromethane (10 ml) and a 1.0 M solution of
boron tribromide methyl sulphide complex in dichloromethane (25.59
mmol) was added. The mixture was heated at reflux over night. The
solvent was evaporated under vacuo and the residue purified by
flash chromatography to obtain ethyl 3-methyl-5-hydroxybenzofuran
carboxylate as a white solid.
[0234] Triphenyl phosphine polymer bound (1.37 mmol) was suspended
in anhydrous dichloromethane (10 ml) then diisopropyl
azodicarboxylate (1.18 mmol) was added and the mixture was stirred
for 15 minutes at room temperature. Then ethyl
3-methyl-5-hydroxybenzofuran carboxylate (0.91 mmol) was added over
5 minutes followed by the addition of
4-N-boc-3-morpholinecarboxylic acid (0.91 mmol) over 5 minutes too.
The mixture was stirred at room temperature over night. The solvent
was evaporated under vacuo and the residue purified by flash
chromatography to obtain ethyl
3-methyl-5-(4-Boc-morpholin-2-ylmethoxy)-benzofuran-2-carboxylate:
m/z=419 in MS ES+, as clear oil.
[0235] Ethyl
3-methyl-5-(4-Boc-morpholin-2-ylmethoxy)-benzofuran-2-carboxylate
(1.05 mmol) was dissolved in 30 ml of a 4.0 M solution of
hydrochloric acid in dioxan and stirred at room temperature for 1
hour. After removing the solvent under vacuo the resulting amine
was dissolved in 20 ml of a mixture 2 to 1 of methanol and a
buffered solution of acetic acid and sodium acetate at pH=5.3. A
37% solution of formaldehyde in water (1.16 mmol) was added and the
mixture was stirred at room temperature for 1 hour. Then sodium
cyanoborohydride (1.16 mmol) was added and the mixture was stirred
over night at room temperature. The methanol was removed under
vacuo and the water was eliminated by liophylisation. The solid
obtained was purified by flash chromatography to yield ethyl
3-methyl-5-(4-methyl-morpholin-2-ylmethoxy)-benzofuran-2-carboxylate:
m/z=334 in MS ES+, as a white solid. Ethyl
3-methyl-5-(4-methyl-morpholin-2-ylmethoxy)-benzofuran-2-carboxylate
(0.12 mmol) was dissolved in 300 .mu.l of tetrahydrofuran. Then 300
.mu.l of a 1.0 M solution of lithium hydroxide were added and the
mixture stirred at room temperature for 3 hours. The
tetrahydrofuran was removed under vacuo and the water eliminated by
lyophilisation to yield the tilted compound as a white solid:
m/z=304 in MS ES-.
4-[2-(1-Dimethylamino-ethyl)-thiazol-5-yl]-benzoic acid lithium
salt (Example 8.38)
4-(2-Azido-acetyl)-benzoic acid methyl ester
[0236] 4-(2-Bromo-acetyl)-benzoic acid methyl ester (15.5 mmol) was
dissolved in ethanol (120 ml) and acetic acid (4.8 ml). Sodium
azide (31 mmol) was added and the reaction stirred at 4.degree. C.
overnight. The ethanol was removed and the mixture diluted with
ethyl acetate (100 ml). The organic layer was washed with saturated
sodium hydrogen carbonate (2.times.50 ml) and dried (MgSO.sub.4).
The solvent was removed in vacuo to give a yellow solid, which was
re-crystallized from ethanol to give the title compound as a pale
yellow solid (2.6 g). IR 2117 cm.sup.-1
[0237] 4-(2-Amino-acetyl)-benzoic acid methyl ester
hydrochloride.
[0238] 4-(2-Azido-acetyl)-benzoic acid methyl ester_(6.53 mmol) was
suspended in methanol (30 ml) and aqueous hydrochloric acid (6.53
mmol, 1M) was added. A catalytic amount of palladium on carbon (10%
wt) was added and the reaction stirred over an atmosphere of
hydrogen for 3 h. The reaction was filtered and the solvent removed
in vacuo to give the title compound (1.3 g) as a yellow solid
m/z=194 in MS ES+, which was used in the next step without
purification.
4-{2-[2-(S)-(tert-Butoxycarbonyl-methyl-amino)-propionylamino]-acetyl}-ben-
zoic acid methyl ester
[0239] 4-(2-Amino-acetyl)-benzoic acid methyl ester hydrochloride
(2.22 mmol), WSC.HCl (2.44 mmol), Boc-N-methyl-(L)-alanine (2.44
mmol) and HOBt (2.77 mmol) were suspended in dichloromethane (10
ml). NMM (2.44 mmol) was added and the reaction stirred for 2 h.
The reaction was diluted with ethyl acetate (50 ml) and washed with
10% citric acid (2.times.25 ml) and saturated sodium hydrogen
carbonate (2.times.25 ml). The organic layer was dried (MgSO.sub.4)
and the solvent removed in vacuo to give a brown oil residue.
Purification by silica chromatography eluting with 10-50% ethyl
acetate/iso-hexane gave the title compound (620 mg) as a pale
yellow oil m/z=379 in MS ES+.
4-{2-(S)-[1-(tert-Butoxycarbonyl-methyl-amino)-ethyl]thiazol-5-yl}-benzoic
acid methyl ester
[0240]
4-{2-[2-(S)-(tert-Butoxycarbonyl-methyl-amino)-propionylamino]-acet-
yl}-benzoic acid methyl ester (1.65 mmol) was dissolved in dry THF
and Lawesson's reagent (2.5 mmol) was added. The reaction was
heated at reflux for 5 h and cooled to room temperature. The
solvent was removed in vacuo and the residue was dissolved in ethyl
acetate (100 ml). The organic layer was washed with 10% citric acid
(2.times.50 ml) and saturated sodium hydrogen carbonate (2.times.50
ml) and dried (MgSO.sub.4). The solvent was removed in vacuo to
give a yellow oil residue, which was purified by silica
chromatography to give the title compound (570 mg) as a pale yellow
solid. 1H NMR (CDCl.sub.3, 400 MHz) 1.5 (s, 9H), 1.6 (d, 7 Hz), 2.8
(brs, 3H), 3.9 (s, 3H), 5.6 (brm, 1H), 7.6 (m, 2H), 7.9 (s, 1H),
8.0 (m, 2H).
4-{2-(S)[1-(tert-Butoxycarbonyl-methyl-amino)-ethyl]-thiazol-5-yl}-benzoic
acid
[0241]
4-{2-(S)[1-(tert-Butoxycarbonyl-methyl-amino)-ethyl]-thiazol-5-yl}--
benzoic acid methyl ester (0.75 mmol) was dissolved in methanol (10
ml) and lithium hydroxide (10 ml, 1M) was added. The reaction was
stirred at room temperature overnight and the methanol removed in
vacuo. The aqueous solution was taken to pH=3 with 1M hydrochloric
acid and extracted with ethyl acetate (2.times.50 ml). The organic
layer was dried (MgSO.sub.4) and the solvent removed in vacuo to
give an off-white powder, which was purified by silica
chromatography eluting with 50-80% ethyl acetate/iso-hexane. The
title compound was obtained as a white powder (252 mg) m/z=363 in
MS ES+.
4-[2-(S)-(1-Dimethylamino-ethyl)-thiazol-5-yl]-benzoic acid methyl
ester
[0242]
4-{2-(S)[1-(tert-Butoxycarbonyl-methyl-amino)-ethyl]-thiazol-5-yl}--
benzoic acid (0.75 mmol) was dissolved in 50% TFA/DCM (2 ml) and
stirred for 1 h. The solvent was removed in vacuo and the residue
placed under high vacuum for 3 h to give a light brown oil residue.
The residue was dissolved in methanol (2 ml) and buffer (1 ml, 1M
sodium acetate/acetic acid, pH=5.5) was added. Formaldehyde (0.83
mmol, 37 wt % in water) was added and the reaction stirred for 30
minutes. Sodium cyanoborohydride (0.83 mmol) was added and the
reaction stirred overnight at room temperature. The methanol was
removed in vacuo and the aqueous diluted with saturated sodium
hydrogen carbonate (25 ml). The aqueous layer was extracted with
ethyl acetate (2.times.25 ml) and the organic layer dried
(MgSO.sub.4). The solvent was removed in vacuo and the residue
purified by silica chromatography to give the title compound (158
mg) as an off-white solid 1H NMR(CD.sub.3OD, 400 MHz) 1.5 (d, J 7
Hz), 2.3 (s, 6H), 3.9 (s, 3H), 3.95 (q, J 7 Hz), 7.7 (m, 2H), 8.0
(m, 3H).
4-[2-(1-Dimethylamino-ethyl)-thiazol-5-yl]-benzoic acid lithium
salt
[0243]
4-{2-(S)-[1-(tert-Butoxycarbonyl-methyl-amino)-ethyl]thiazol-5-yl}--
benzoic acid (0.54 mmol) was dissolved in methanol (2 ml) and
lithium hydroxide (0.54 mmol, 1M) was added. The reaction was
stirred overnight and the methanol removed in vacuo. The residue
was diluted with water (5 ml) and the aqueous layer extracted with
ethyl acetate. The aqueous layer was freeze-dried to give the title
compound as an off-white solid (143 mg) which was used in the next
step without further purification m/z=277 in MS ES+.
5-N,N-Dimethylamino-1H-indole-2-carboxylic acid (Example 8.39)
5-Amino-1H-indole-2-carboxylic acid ethyl ester
[0244] 5-Nitro-1H-indole-2-carboxylic acid ethyl ester (14.9 mmol)
was suspended in acetone (50 ml) and added to a mixture of
titanium(III) chloride (91 ml, >10% in 2M hydrochloric acid) and
ammonium acetate (265 ml, 4M). The reaction was stirred for 2 h and
neutralized with saturated sodium hydrogen carbonate. The mixture
was extracted with ethyl acetate (100 ml) and the organic layer
dried (MgSO.sub.4). The solvent was removed in vacuo to give a
light brown solid which was purified by silica chromatography to
give the title compound as an off-white solid (1.57 g) m/z=205 in
MS ES+.
5-N,N-Dimethylamino-1H-indole-2-carboxylic acid ethyl ester
[0245] 5-Amino-1H-indole-2-carboxylic acid ethyl ester (7.7 mmol)
was dissolved in acetonitrile (30 ml) and formaldehyde (19.2 mmol,
37% wt in water) was added. Sodium cyanoborohydride (7.7 mmol) was
added and the reaction stirred at room temperature overnight. The
acetonitrile was removed in vacuo and the residue was purified by
silica chromatography to give the title compound was a pale yellow
solid (244 mg). m/z=233 in MS ES+.
5-N,N-Dimethylamino-1H-indole-2-carboxylic acid
[0246] 5-N,N-Dimethylamino-1H-indole-2-carboxylic acid ethyl ester
(1.05 mmol) was suspended in ethanol (1 ml) and lithium hydroxide
(1.2 ml, 1M in water) was added. The reaction was stirred at room
temperature overnight. The solution was taken to pH=7 with 1M
hydrochloric acid and the ethanol removed in vacuo. The aqueous
layer was extracted with ethyl acetate and the organic layer dried
(MgSO4). The ethyl acetate was removed in vacuo to give the title
compound as a yellow powder (75 mg), which was used in the next
step without purification. m/z=205 in MS ES+.
4-{2-[1-(tert-Butoxycarbonyl-methyl-amino)-ethyl]thiazol-4-yl}-benzoic
acid (Example 8.40)
[0247] Boc-L-NMe-Alanine-OH (1.0 g, 4.92 mmols) was dissolved in
dioxan (10 mls) and to this was added pyridine (0.25 mLs),
di-tert-butyl dicarbonate (1.4 g, 6.4 mmols) and ammonium hydrogen
carbonate (0.49 g, 6.2 mmols). After stirring for 18 hours the
crude reaction mixture was concentrated in vacuo and re-suspended
in ethyl acetate. This was washed with 1M KHSO.sub.4 and the
organic layer dried over magnesium sulphate. After concentration a
clear oil was obtained (0.79 g). This was dissolved in ethylene
glycol dimethyl ether (10 mls) and to this was added Lawesson's
reagent (4.31 mmols, 1.74 g). After stirring at room temperature
for 3 hours the reaction mixture was concentrated in vacuo and the
residue re-suspended in ethyl acetate. This was washed with 1M
Na.sub.2CO.sub.3 and the organic layer dried over magnesium
sulphate. After concentration a yellow oil was obtained. This was
purified by flash chromatography (heptane/ethyl acetate) to give a
white solid (0.73 g). This was dissolved in ethanol (10 mls) and
4-(2-Bromo-acetyl)-benzoic acid methyl ester (3.34 mmols, 0.86 g)
was added. The reaction was heated to 50.degree. C. for one hour.
The crude product was purified by flash chromatography
[0248] (heptane/ethyl acetate) to give a white solid (0.39 g). ESMS
(M+H=377.23) which was subsequently hydrolysed to the corresponding
acid.
4-[2-(1-Dimethylamino-2-methoxy-ethyl)-thiazol-4-yl]-benzoic acid
(Example 8.41)
[0249] Boc-L-Serine(OMe)-OH (2.4 g, 6.0 mmols) was dissolved in
dioxan (20 mls) and to this was added pyridine (0.31 mls),
di-tert-butyl dicarbonate (1.7 g, 7.8 mmols) and ammonium hydrogen
carbonate (0.62 g, 7.2 mmols). After stirring for 18 hours the
crude reaction mixture was concentrated in vacuo and re-suspended
in ethyl acetate. This was washed with 1M KHSO.sub.4 and the
organic layer dried over magnesium sulphate. After concentration
the crude product was purified by flash chromatography to yield
0.55 g of a clear oil. This was dissolved in ethylene glycol
dimethyl ether (20 mls) and to this was added Lawesson's reagent
(2.78 mmols). After stirring at room temperature for 3 hours the
reaction mixture was concentrated in vacuo and the residue purified
by flash chromatography (silica gel, DCM) to give a yellow oil
(2-Methoxy-1-thiocarbamoyl-ethyl)-carbamic acid tert-butyl ester
(0.49 g).
[0250] The ester (0.25 g, 1.07 mmols) was dissolved in ethanol (10
mls) and 4-(2-Bromo-acetyl)-benzoic acid methyl ester (1.18 mmols,
0.30 g) was added. The reaction was heated to 50.degree. C. for one
hour. The crude product was purified by preparative HPLC
(MeCN/H.sub.2O) to yield 0.138 g of a yellow solid. The Boc group
was removed via treatment with 4M HCl/dioxan for one hour after
which time the reaction mixture was concentrated in vacuo. The free
amine (0.093 g, 0.265 mmols) was then dimethylated. The crude HCl
salt was dissolved in 5 mls of methanol and buffered with 2.5 mls
pH 5.5 Sodium acetate/acetic acid. Formaldehyde was added (0.58
mmols) and the reaction stirred for one hour. Sodium
cyanoborohydride was then added (0.58 mmols, 0.036 g) and the
reaction stirred for a further thirty minutes. The reaction mixture
was concentrated in vacuo and purified by preparative HPLC to yield
60 mg of a yellow solid. Finally, the methyl ester was hydrolysed
with 1M LiOH (5 mls) and dioxan (5 mls) at room temperature for two
hours. The reaction mixture was concentrated in vacuo and
lyophilised from water to yield 62 mg of the desired acid as the
lithium salt. ESMS (M+H=307.04)
4-[2-(4-Fluoro-1-methyl-pyrrolidin-2-yl]-thiazol-4-yq-benzoic acid
(Example 8.42)
[0251]
4-Fluoro-2-[4-(4-methoxycarbonyl-phenyl)-thiazol-2-yl]-pyrrolidine--
1-carboxylic acid tert-butyl ester (0.1 g) was treated with 4M
HCl/dioxan (10 mls) for 2 hours. The reaction mixture was then
concentrated in vacuo and lyophilised from water to yield a yellow
solid (0.8 g). The crude HCl salt was dissolved in 5 mls of
methanol and buffered with 2.5 mls pH 5.5 Sodium acetate/acetic
acid. Formaldehyde was added (0.38 mmols, 0.0032 mls) and the
reaction stirred for one hour. Sodium cyanoborohydride was then
added (0.38 mmols, 0.024 g) and the reaction stirred for a further
thirty minutes. The reaction mixture was concentrated in vacuo and
the residue re-suspended in ethyl acetate. This was washed with 1M
Na.sub.2CO.sub.3 and the organic layer dried over magnesium
sulphate. After concentration a yellow solid was obtained (0.075
g). Finally, the methyl ester was hydrolysed with 1M LiOH (5 mls)
and dioxan (5 mls) at room temperature for two hours. The reaction
mixture was concentrated in vacuo and lyophilised from water to
yield 62 mg of the desired acid as the lithium salt. ESMS
(M+H=306.88)
2-[4-(4-Carboxy-phenyl)-thiazol-2-yl]-4-fluoro-pyrrolidine-1-carboxylic
acid (Example 8.43)
[0252]
2-[4-(4-Carboxy-phenyl)-thiazol-2-yl]-4-fluoro-pyrrolidine-1-carbox-
ylic acid tert-butyl ester The amide (0.32 g, 1.37 mmols) was
dissolved in ethylene glycol dimethyl ether (10 mls) and to this
was added Lawesson's reagent (0.61 g, 1.5 mmols). After stirring at
room temperature for 3 hours the reaction mixture was concentrated
in vacuo and the residue re-suspended in ethyl acetate. This was
washed with 1M Na.sub.2CO.sub.3 and the organic layer dried over
magnesium sulphate. After concentration a yellow oil was obtained.
This was purified by flash chromatography (heptane/ethyl acetate)
to give a white solid (0.36 g). This was dissolved in ethanol (10
mls) and 4-(2-Bromo-acetyl)-benzoic acid methyl ester (0.41 g,1.59
mmols) was added. The reaction was heated to 50.degree. C. for one
hour. The crude product was purified by flash chromatography
(heptane/ethyl acetate) to give a white solid (0.34 g). The methyl
ester was then treated with 1M LiOH (10 mls) and dioxan (10 mls)
for 3 hours. After quantitative hydrolysis, the crude product was
concentrated in vacuo and the residue re-suspended in ethyl
acetate. This was washed with 1M KHSO.sub.4 and the organic layer
dried over magnesium sulphate. After concentration in vacuo the
product was lyophilised from acetonitrile/water to yield the title
compound as a white solid (0.32 g). ESMS (M+H=393.03).
Lithium 5-(4-N-methylmorpholino-2S-methyloxy)benzofuran carboxylate
(Example 8.36 as single enantiomers)
Ethyl 5-(4-boc-morpholino-2R-methyloxy)benzofuran carboxylate
[0253] 4-Boc-2R-hydroxymethylmorpholine was prepared according to
method described in Heterocycles, 1993 35, 105-109. To a mixture of
polymer supported triphenylphosphine (2.4 mmol) and the
hydroxymethylmorpholine (1.2 mmol) in dry dichloromethane (5 ml)
ethyl-5-hydroxybenzofuran-2-carboxylate (1.2 mmol) and DIAD (1.2
mmol) was added at room temperature. The mixture was stirred
further 16 hours, fitrated, diluted in dry dichloromethane (5 ml)
and stirred at room temperature another 16 hours.
[0254] Filtrated, concentrated in vacuo and purified by y flash
chromatography on silica (ethylacetate, hexane)to yield
ethyl-5-(4-boc-morpholino-2R-methyloxy)benzofuran carboxylate (0.3
mmol), m/z=406 in MS ES+, as an oil.
[0255] Lithium 5-(4-N-methylmorpholino-2R-methyloxy)benzofuran
carboxylate.
[0256] Ethyl-5-(4-boc-morpholino-2R-methyloxy)benzofuran
carboxylate (0.3 mmol) was dissolved in HCl in dioxane (4M, 15 ml),
stirred at room temperature for 4 hours, concentrated in vacuo to a
pale yellow oil. The crude benzofuran hydrochloride (0.3 mmol) and
formaldehyde (0.35 mmol) were mixed in THF (5 mL) and dibutyltin
dichloride (0.05 mmol) was added. After stirring at RT for 5
minutes, phenylsilane (0.6 mmol) was added and the reaction allowed
to stir at room temperature for a further 17 h. The reaction was
then concentrated in vacuo and the residue purified by flash
chromatography (silica gel, ethyl acetate, isopropanol,
triethylamine) to give
ethyl-5-(4-N-methylmorpholino-2R-methyloxy)benzofuran carboxylate:
m/z=320 in MS ES+as a clear oil.
[0257] To ethyl-5-(4-N-methylmorpholino-2R-methyloxy)benzofuran
carboxylate (0.6 mmol) in 5 ml dioxane was added LiOH (0.6 mmol) in
1 ml of water. The mixture was refluxed for 16 hours, concentrated
in vacuo to give lithium
5-(4-N-methylmorpholino-2R-methyloxy)benzofuran carboxylate: m/z
292 in MS ES+as a white solid.
[0258] Lithium 5-(4-N-methylmorpholino-2S-methyloxy)benzofuran
carboxylate.
[0259] S-isomer: m/z 292 in MS ES+was prepared as a white solid
white solid according to method used to prepare R-isomer but
substituting 4-Boc-2R-hydroxymethylmorpholine by
4-Boc-2S-hydroxymethylmorpholine.
4-(3-Methyl-5-morpholino-4-ylmethyl-thiophen-2-yl)-benzoic acid
(Example 8.44)
[0260] 5-Bromo-4-methyl-thiophene-2-carboxylic acid methyl ester
(8.51 mmol) was dissolved in EtOH (100 ml) and NaOH (42.5 mmol)
added, as a 1M solution in water. Reaction was heated to 80.degree.
C. for 2 h, after which time all starting material had been
consumed. Reaction was then concentrated in vacuo and the residue
taken up in DCM and shaken with 1M HCl. The resulting biphasic
mixture was then filtered and the filtrant washed with hexane and
dried under vacuum. This gave
5-Bromo-4-methyl-thiophene-2-carboxylic acid as off white solid:
m/z in MS AP-=219, 221 [M-H].sup.-, 6.79 mmol, 80%.
5-Bromo-4-methyl-thiophene-2-carboxylic acid (6.79 mmol) was taken
up in 30 ml DMF and morpholine (7.47 mmol), WSC.HCl (7.47 mmol) and
HOBt (7.47 mmol) were added. Reaction was stirred at room
temperature for 17 h and then diluted with EtOAc, washed with 1M
HCl and brine, dried over Na.sub.2SO.sub.4 and concentrated in
vacuo. Flash chromatography of the residue (silica, 33-50% EtOAc in
hexane) gave
(5-Bromo-4-methyl-thiophen-2-yl)-morpholin-4-yl-methanone as a pale
golden oil: m/z in MS ES+=290, 292 [m+H].sup.+, 4.67 mmol, 69%.
[0261] (5-Bromo-4-methyl-thiophen-2-yl)-morpholin-4-yl-methanone
(1.78 mmol) was added to a flask containing 1M THF.BH.sub.3 complex
in THF (4.45 mmol). Reaction was stirred at reflux for 2.5 h under
N.sub.2. Methanol was then added until gas evolution ceased,
followed by 10 ml of 1M NaOH and the reaction stirred at reflux for
a further 7 h. The mixture was cooled to room temperature and
extracted with EtOAc. This extract was concentrated in vacuo and
the residue taken up in 1M HCl and washed with EtOAc. The acid
layer was then basified with 1M NaOH and extracted back into EtOAc.
Removal of solvent gave
4-(5-Bromo-4-methyl-thiophen-2-ylmethyl)-morpholine as a colourless
oil: m/z in MS ES+=276, 278 [M+H].sup.+, 0.98 mmol, 55%.
[0262] 4-(5-Bromo-4-methyl-thiophen-2-ylmethyl)-morpholine (0.98
mmol) was taken up in 10 ml toluene and
4-carboxymethylphenylboronic acid (0.98 mmol) was added as a
solution in 1 ml of EtOH. 6 ml of 2M aqueous Na.sub.2CO.sub.3
solution was added, followed by Pd(PPh.sub.3).sub.4 (0.098 mmol).
Reaction was stirred at 70.degree. C. for 17 h under a nitrogen
atmosphere and then cooled to room temperature and extracted with
DCM (.times.2). Combined organic layers were washed with brine,
concentrated in vacuo and the residue purified by flash
chromatography (silica, 33-99% EtOAc in hexane). This furnished the
pure 4-(3-Methyl-5-morpholi-4-ylmethyl-thiophen-2-yl)-benzoic acid
methyl ester as a waxy white solid: m/z in MS ES+=332 [M+H].sup.+,
0.090 mmol, 9%.
[0263] This ester (0.09 mmol) was heated to 70.degree. C. in 18%
HCl for 2 h at which point HPLC showed all the starting material to
have been hydrolysed. The reaction was cooled and the product that
precipitated out of solution was collected by filtration as a white
solid. With no further purification this was coupled using the
standard procedure.
3-Methyl-4-(5-morpholin-4-ylmethyl-furan-2-yl)-benzoic acid
(Example 8.45)
[0264] A three necked flask was charged with methyl
4-bromo-3-methylbenzoate (2.18 mmol), bis(pinacolato)diboron (2.29
mmol), palladium acetate (0.065 mmol), potassium acetate (6.54
mmol) and DMF (10 ml). The solution was degassed by bubbling
through N.sub.2 gas for 30 mins and was then heated to 80.degree.
C. under N.sub.2 for 3 h. Reaction was then cooled to room
temperature and 4-(5-Bromo-furan-2-ylmethyl)-morpholine (2.18
mmol), cesium carbonate (3.27 mmol) and Pd(PPh3)4 (0.065 mmol)
added. The reaction was heated to 80.degree. C. and stirred for a
further 17 h. Mixture was then diluted with EtOAc and water and
filtered through a celite pad to remove black particulates. The
organic layer was separated, washed with brine and dried over
Na.sub.2SO.sub.4 and concentrated in vacuo. Flash chromatography of
the residue (silica, 10-99% EtOAc in hexane) gave
3-Methyl-4-(5-morpholin-4-ylmethyl-furan-2-yl)-benzoic acid methyl
ester as a grey powdery solid: m/z in MS ES+=316 [M+H].sup.+, 0.51
mmol, 23%.
[0265] This ester (0.51 mmol) was heated to 70.degree. C. in 18%
HCl for 2 h at which point HPLC showed all the starting material to
have been hydrolysed. The reaction was cooled and the product that
precipitated out of solution was collected by filtration as a white
solid. With no further purification this was coupled using the
standard procedure.
4-[5-Methyl-2-(4-methyl-piperazin-1-yl)-thiazol-4-yl]-benzoic acid
(Example 8.46)
[0266] 4-propionylbenzoic acid (890 mg, 5 mmol), NaHCO.sub.3 (1.26
g, 15 mmol), and iodomethane (935 4, 15 mmol) in DMF (10 mL) were
stirred at RT overnight. The mixture was diluted with saturated
aqueous NaCl (50 mL) and extracted with ether (3.times.50 mL). The
organic phase was washed with water (50 mL), dried, and evaporated.
Flash chromatography (90 g silica, 2/1 petroleum ether--EtOAc) gave
white solids of 4-Propionyl-benzoic acid methyl ester (744 mg,
77%).
[0267] 1H NMR (CDCl.sub.3, 400 MHz) .delta. 1.24 (t, 3H, J=7 Hz),
3.03 (q, 2H, J=7 Hz), 3.95 (s, 3H), 8.0 and 8.12 (ABq, 4H)
[0268] 4-Propionyl-benzoic acid methyl ester (744 mg, 3.87 mmol),
pyrrolidone hydrotribromide (1.98 g), and 2-pyrrolidinone (380 mg,
4.5 mmol) in THF (38 mL) were heated at 50.degree. C. under
nitrogen for 3 h. The mixture was cooled, filtered, concentrated,
and then redissolved in ether (50 mL). The ether solution was
washed successively with water (20 mL), saturated aqueous sodium
thiosulphate (20 mL), saturated aqueous NaCl (20 mL), and water (20
mL), dried and evaporated to give crude
4-(2-Bromo-propionyl)-benzoic acid methyl ester as a yellow oil
(1.025 g) that was used directly in the Hantzsch coupling. This
material contained 91% of the desired bromoketone, 5% starting
material, and 4% 4-bromo-1-butanol, as determined by .sup.1H
NMR.
[0269] 1H NMR (CDCl.sub.3, 400 MHz) .delta. 1.92 (d, 3H, J=7 Hz),
3.96 (s, 3H), 5.28 (q, 1H, J=7 Hz), 8.07 and 8.14 (ABq, 4H)
[0270] All of the 4-(2-Bromo-propionyl)-benzoic acid methyl ester
above and piperazine-1-carboxylic acid tert-butyl ester (J. Med.
Chem., 1998, 5037-5054, 917 mg, 3.73 mmol) were refluxed in 36 mL
THF at 70.degree. C. for 2 h, under N.sub.2. The precipitate was
filtered and the filtrate evaporated to give yellow solids. Flash
column chromatography (silica, 5/1 petroleum ether--EtOAc) gave 624
mg of
4-[4-(4-Methoxycarbonyl-phenyl)-5-methyl-thiazol-2-yl]-piperazine-1-ca
[0271] rboxylic acid tert-butyl ester as a light yellow solid.
Chromatography of the precipitate (silica, 2/1 petroleum
ether--EtOAc) gave 32 mg more of compound. Total yield is 44%.
[0272] 1H NMR (CDCl.sub.3, 400 MHz) .delta. 1.46 (s, 9H), 2.43 (s,
3H), 3.42, (m, 4H), 3.54 (m, 4H), 3.90 (s, 3H), 7.68 and 8.04 (ABq,
4H).
[0273] The above methyl ester (564 mg, 1.35 mmol) was heated with
1.35 mL 2N NaOH, 5 mL THF, and 3.65 mL water at 60.degree. C. for 4
h. The reaction mixture was evaporated, poured into 20 mL saturated
aqueous NaCl and 20 mL CH.sub.2Cl.sub.2, and then acidified to pH 3
with 5% citric acid, in an ice bath. The layers were separated and
the organic phase was extracted further with 2.times.10 mL
CH.sub.2Cl.sub.2. The organic phases were combined, washed with
water (10 mL), dried, and evaporated to give
4-[4-(4-Carboxy-phenyl)-5-methyl-thiazol-2-yl]-piperazine-1-carboxylic
acid tert-butyl ester as a light yellow solid (537 mg, 98%).
[0274] 1H NMR (CDCl.sub.3, 400 MHz) .delta. 1.48 (s, 9H), 2.47 (s,
3H), 3.47 (m, 4H), 3.57 (m, 4H), 7.74 and 8.12 (ABq, 4H).
[0275] 13C NMR (CDCl.sub.3, 100 MHz) 8 ppm: 12.6, 28.3, 42.8, 48.1,
80.3, 119.1, 127.8, 128.2, 130.1, 140.5, 145.6, 154.6, 167.2,
171.4.
[0276] LCMS: (M+H).sup.+ 404, (M-H).sup.- 402.
4-[4-(4-Carboxy-phenyl)-5-methyl-thiazol-2-yl]-piperazine-1-carboxylic
[0277] acid tert-butyl ester (0.421 mmol) was dissolved in 4M HCl
in 1,4-dioxane, and stirred at room temperature for 1 h. The
solvent was then removed under vacuum, and the residue
4-(5-Methyl-2-piperazin-1-yl-thiazol-4-yl)-benzoic acid was
suspended in methanol (10 ml) and treated with AcOH/AcONa buffer
(pH-5.5, 5 ml), and formaldehyde (0.547 mmol). The reaction mixture
was stirred at room temperature for 1 h, then treated with
NaCNBH.sub.3 (0.547 mmol) and stirred at room temperature
overnight. The solvent was then removed under vacuum, and the
residue was purified by column chromatography to afford the title
compound (0.403 mmol, 95%). MS (ES) m/z 318 (100%,
[M+H].sup.+).
4-(2-Morpholin-4-yl-thiazol-4-yl)-benzoic acid (Example 8.47)
[0278] 4-(2-bromoacetyl)benzoic acid (1.23 mmol) and
1-morpholinethiocarboxamide (1.23 mmol, J. Med. Chem. 1998, 41,
5037-5054) were mixed in THF (10 mL), then refluxed for 3.5 h. The
reaction mixture was then allowed to reach room temperature and the
obtained precipitate was collected by filtration and washed with 4
portions of diethyl ether. The crude product was crystallized from
hot 1:1 EtOH-EtOAc to give a first harvest of colorless needles
(0.16 g, 0.55 mmol). .sup.1H NMR (DMSO-d.sub.6, 400 MHz) .delta.
7.94 (4H, m), 7.49 (1H, s), 3.72 (4H, m), 3.44 (4H, m).
4-(2-Piperidin-1-yl-thiazol-4-O-benzoic acid (Example 8.48)
[0279] 4-(2-bromoacetyl)benzoic acid (1.23 mmol) and
1-piperidinethiocarboxamide (1.23 mmol) were mixed in THF (10 mL),
then refluxed for 3 h. The reaction mixture was then allowed to
reach room temperature and the obtained precipitate was collected
by filtration and washed with 3 portions of diethyl ether. The
crude product was crystallized from hot 1:1 EtOH-EtOAc to give a
first harvest of colorless needles (0.28 g, 0.95 mmol). 1H NMR
(DMSO-d.sub.6, 400 MHz,) .delta. 7.93 (4H, m), 7.40 (1H, s), 3.48
(4H, m), 1.60 (6H, m).
4-(2-Dimethylamino-thiazol-4-yl)-benzoic acid (Example 8.49)
[0280] To a stirred mixture of thiocarbonyldiimidazole (44.9 mmol)
in THF (40 mL) at room temperature was added portionwise 2 M
Dimethylamine in THF (44 mmol) and a temperature increase was
observed. 40 min after final addition the reaction mixture was
heated to 55.degree. C. for 1 h, then allowed to reach room
temperature again. The reaction was then concentrated in vacuo and
the residue purified by flash chromatography (silica gel, Petroleum
ether-EtOAc) to give the intermediate Imidazole-1-carbothioic acid
dimethylamide. This material was treated with freshly prepared sat.
ammonia in methanol (40 ml) for 60 h, then concentrated in vacuo
and the precipitated residue was suspended in diethyl ether and
collected by filtration. The precipitate was washed with diethyl
ether and air-dried to give a slight yellow solid (1.71 g, 16.4
mmol) which was used in the subsequent step.
4-(2-bromoacetyl)benzoic acid (1.23 mmol) and
1-piperidinethiocarboxamide (1.23 mmol) were mixed in THF (10 mL),
then refluxed for 3 h. The reaction mixture was then allowed to
reach room temperature and the obtained precipitate was collected
by filtration and washed with 3 portions of diethyl ether. The
crude product was crystallized from hot 1:1 EtOH-EtOAc to give a
first harvest of colorless needles (0.1 g, 0.40 mmol). .sup.1H NMR
(DMSO-d.sub.6,400 MHz) .delta. 7.94 (4H, m), 7.37 (1H, s), 3.11
(6H, m).
4-[2-(Isopropyl-methyl-amino)-5-methyl-thiazol-4-yl]-benzoic acid
(Example 8.50)
[0281] To a solution of 4-propionylbenzoic acid (11.2 mmol), benzyl
alcohol (1.1 mL, 10.7 mmol) and dimethylaminopyridine (0.14 g, 1.1
mmol) in dichloromethane (90 ml) at 0.degree. C. was added
N-Ethyl-N'-(3-dimethylaminopropyl)carbodiimide.times.HCl (2.4 g,
12.3 mmol), then stirred at room temperature overnight. The
obtained solution was then diluted with DCM, washed successively
with aq. 10% citric acid and aq. sat. sodium hydrogen carbonate,
then dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo.
Flash chromatography of the residue (silica gel, Petroleum
ether-EtOAc) gave a colorless oil which crystallized upon standing
(2.67 g). A portion of the benzyl ester from above (1 g, 3.73 mmol)
was refluxed with 2-pyrrolidinone (0.37 g, 4.33 mmol) and
pyrrolidone hydrotribromide (1.85 g, 3.73 mmol) in THF for 1.5 h.
The resulting reaction mixture was allowed to reach room
temperature, then diluted with EtOAc, washed successively with
water, aq. 10% sodium thiosulphate, aq. sat. sodium hydrogen
carbonate and brine, then dried (Na.sub.2SO.sub.4), filtered and
concentrated in vacuo. The obtained bromide from above was directly
mixed with isopropylthiocarboxamide (0.44 g, 3.73 mmol) in THF (20
mL) and refluxed overnight, then concentrated onto silica. Flash
chromatography of the residue (silica gel, Petroleum
ether-EtOAc-Et.sub.3N) gave a light red oil (1.28 g, 3.49 mmol). To
a stirred solution of the thiazole derivative (0.250 g, 0.68 mmol),
obtained above, in acetonitrile (7 mL), acetic acid (1.3 mL) and
aq. 37% formaldehyde (2 mL) at 0.degree. C. was added sodium
cyanoborohydride (0.09 g), then stirred at room temperature
overnight. Additional sodium cyanoborohydride (0.08 g) was added,
and after stirring for additional 2 h, the reaction mixture was
diluted with water, neutralized using aq. 0.5 M sodium carbonate,
then extracted wih dichloromethane. The dichloromethane layers were
collected, dried (Na.sub.2SO.sub.4), filtered and concentrated.
Flash chromatography (silica gel, Petroleum ether-EtOAc) of the
residue gave a slight yellow crystalline solid (0.115 g). 1H NMR
(CDCl.sub.3, 400 MHz,) .delta. 8.09 (2H, d), 7.72 (2H, d),
7.27-7.32 (5H, m), 5.38 (2H, s), 4.27 (1H, m), 2.92 (3H, s), 2.42
(3H, s), 1.22 (6H, d). The benzyl ester from above (0.25 g, 0.66
mmol) was hydrolysed by treating with aq. 1M LiOH (1.3 mL) in THF
(2 mL) at 60.degree. C. overnight. The obtained solution was then
made slight acidic with aq. 10% citric acid and then extracted
using dichloromethane. The organic layer was then dried
(Na.sub.2SO.sub.4), filtered and concentrated. Column
chromatography of the residue (Silica gel,
dichloromethane-methanol) gave the title compound as a crystalline
solid (0.19 g) m/z=304 in MS ES+, which was characterised by hplc
and MS.
4-(2-Methylamino-thiazol-4-yl)-benzoic acid (Example 8.51)
[0282] To 25 ml of ethanol were added 4-(2-bromoacetyl)benzoic acid
(486 mg, 2 mmole) and N-methyl thiourea (180 mg, 2 mmole). The
reaction mixture was refluxed for 3 hr and the TLC showed the
disappearing of the starting materials and the formation of a
fluorescent product. The reaction was cooled on ice. The product
was collected on filtration and washed with ethanol pre-cooled to
0.degree. C. twice (2.times.3 ml), followed by diethyl ether. After
drying, 486 mg product was obtained. .sup.1H NMR (DMSO-d.sub.6, 400
MHz) .delta. 7.97 (2H, d), 7.89 (2H, d), 7.32 (1H, s), 2.96 (3H,
s).
442-(4,4-Difluoro-piperidin-1-yl)-thiazol-4-yq-benzoic acid
(Example 8.52)
[0283] 4,4-difluoropiperidine (hydrochloride salt, 1.57 g, 10
mmole) and diisopropylethylamine (1.74 ml, 10 mmole) in acetone (10
ml) was slowly dropped into a mixture of
ethoxycarbonylisothiocyanate (1.02 ml, 10 mmole) in aceton (10 ml)
at 0.degree. C. When the addition was completed, the reaction was
kept under stirring at room temperature for one hour. 3N
hydrochloric acid (15 ml) was added and the reaction mixture was
extracted with ethyl acetate. The organic phase was concentrated in
vacuo.
[0284] To the residue was added concentrated hydrochloric acid (20
ml) and the reaction was kept at 80.degree. C. for 5 hours. Water
(30 ml) was added to the reaction. After the neutralization with
ammonium carbonate, the reaction mixture was extracted with ethyl
acetate. The organic phase was washed with water and dried in vacuo
to obtain the crude intermediate
4,4-Difluoro-piperidine-1-carbothioic acid amide (1.21 g). To the
residue from above (360 mg, 2 mmole) and 4-(2-bromoacetyl)benzoic
acid (486 mg, 2 mmole) in THF (20 ml) were refluxed for 5 hours.
TLC showed the disappearing of the starting materials and the
formation of a fluorescent product. The reaction was cooled on ice.
The solid was collected by filtration. The product was
recrystallized from ethanol (380 mg). 1H NMR (DMSO-d.sub.6, 400
MHz) .delta. 7.96 (4H, m), 7.51 (1H, s), 3.66 (4H, m) 2.12 (4H,
m).
[0285] Yields of the following title compounds in examples
8.53-8.61 and 8.63 were in general between 30 and 90%.
4-(2-Isopropylamino-thiazol-4-yl)-benzoic acid (Example 8.53)
[0286] Isopropyl-thiourea (2.47 mmol) and
4-(2-Bromo-acetyl)-benzoic acid (2.47 mmol) were mixed in THF (12
mL). After stirring at room temperature for 5 minutes the mixture
was heated to 80.degree. C. for 2 hours. The volume was reduced to
5 mL and the mixture was then cooled to -20.degree. C. and
filtered. The solid was washed with a small amount of diethylether
and dried. m/z=263.1 in MS ES+, which was characterized by hplc and
MS and used in the next step without any further purification.
3-[2-(4-Methyl-piperazin-1-yl)-thiazol-4-yl]-benzoic acid (Example
8.54)
[0287] 4-Methyl-piperazine-1-carbothioic acid amide (2.47 mmol) and
3-(2-Bromo-acetyl)-benzoic acid (2.47 mmol) were mixed in THF (12
mL). After stirring at room temperature for 5 minutes the mixture
was heated to 80.degree. C. for 2 hours. The mixture was then
cooled to room temperature and filtered. The solid was washed with
a small amount of diethylether and dried. m/z=304.1 in MS ES+,
which was characterized by hplc and MS and used in the next step
without any further purification.
3-(2-Isopropylamino-thiazol-4-yl)-benzoic acid (Example 8.55)
[0288] Isopropyl-thiourea (2.47 mmol) and
3-(2-Bromo-acetyl)-benzoic acid (2.47 mmol) were mixed in THF (12
mL). After stirring at room temperature for 5 minutes the mixture
was heated to 80.degree. C. for 2 hours. The volume was reduced to
5 mL and the mixture was then cooled to -20.degree. C. and
filtered. The solid was washed with a small amount of diethylether
and dried. m/z=263.1 in MS ES+, which was characterized by hplc and
MS and used in the next step without any further purification.
4-(2-Piperidin-4-yl-thiazol-4-yl)-benzoic acid (Example 8.56)
[0289] 4-Thiocarbamoyl-piperidine-1-carboxylic acid tert-butyl
ester (2.47 mmol) and 4-(2-Bromo-acetyl)-benzoic acid (2.47 mmol)
were mixed in THF (12 mL). After stirring at room temperature for 5
minutes the mixture was heated to 80.degree. C. for 2 hours. The
volume was reduced to 5 mL and diethylether (5 mL) was added. The
mixture was then cooled to -20.degree. C. and filtered. The solid
was washed with a small amount of diethylether and dried. m/z=289.1
in MS ES+, which was characterized by hplc and MS and used in the
next step without any further purification.
4-[2-(1-Methyl-piperidin-4-yl)-thiazol-4-yl]-benzoic acid (Example
8.57)
[0290] To a solution of 4-(2-Piperidin-4-yl-thiazol-4-yl)-benzoic
acid (1 mmol) in acetic acid (0.5 mL), methanol (3 mL) and
tetrahydrofurane (4.5 mL) was added formaldehyde (aq. 37%, 300 mL)
and polystyrene bound cyanoborohydride (2.36 mmol/g, 900 mg). The
slurry was then agitated for 16 hours at room temperature. The
slurry was then filtered and the resin washed with methanol (2 mL).
The solution was concentrated to dryness in vacuo. m/z=303.1 in MS
ES+, which was characterized by hplc and MS and used in the next
step without any further purification.
4-[2-(Pyridin-3-ylamino)-thiazol-4-yl]-benzoic acid (Example
8.58)
[0291] Pyridin-3-yl-thiourea (2.06 mmol) and
4-(2-Bromo-acetyl)-benzoic acid (2.06 mmol) were mixed in THF (12
mL). After stirring at room temperature for 5 minutes the mixture
was heated to 80.degree. C. for 2 hours. The mixture was then
cooled to room temperature and filtered. The solid was washed with
a small amount of diethylether and dried. m/z=298.0 in MS ES+,
which was characterized by hplc and MS and used in the next step
without any further purification.
4-[2-(Pyridin-2-ylamino)-thiazol-4-yl]-benzoic acid (Example
8.59)
[0292] Pyridin-2-yl-thiourea (2.06 mmol) and
4-(2-Bromo-acetyl)-benzoic acid (2.06 mmol) were mixed in THF (12
mL). After stirring at room temperature for 5 minutes the mixture
was heated to 80.degree. C. for 2 hours. The mixture was then
cooled to room temperature and filtered. The solid was washed with
a small amount of diethylether and dried. m/z=298.0 in MS ES+,
which was characterized by hplc and MS and used in the next step
without any further purification.
4-(2-Cyclopentylamino-thiazol-4-yl)-benzoic acid (Example 8.60)
[0293] Isothiocyanato-cyclopentane (4 g) in ammonia (37% in water,
8 mL) and methanol (32 mL) was stirred for 16 hours, filtered of
and dried. The Cyclopentyl-thiourea (2.06 mmol) and
4-(2-Bromo-acetyl)-benzoic acid (2.06 mmol) were mixed in THF (12
mL). After stirring at room temperature for 5 minutes the mixture
was heated to 80.degree. C. for 2 hours. The mixture was then
cooled to room temperature and filtered. The solid was washed with
a small amount of diethylether and dried. m/z=289.05 in MS ES+,
which was characterized by hplc and MS and used in the next step
without any further purification.
4-(2-Cyclopropylamino-thiazol-4-yl)-benzoic acid (Example 8.61)
[0294] Isothiocyanato-cyclopropane (4 g) was mixed with ammonia
(37% in water, 8 mL) and methanol (32 mL) at 0.degree. C. and then
stirred for 16 hours at room temperature. The mixture was then
cooled to 0.degree. C., filtered, washed with a little water and
dried. The Cyclopropyl-thiourea (2.06 mmol) and
4-(2-Bromo-acetyl)-benzoic acid (2.06 mmol) were mixed in THF (12
mL). After stirring at room temperature for 5 minutes the mixture
was heated to 80.degree. C. for 2 hours. The mixture was then
cooled to room temperature and filtered. The solid was washed with
a small amount of diethylether and dried. m/z=261.0 in MS ES+,
which was characterized by hplc and MS and used in the next step
without any further purification.
4[2-(Cyclopropyl-methyl-amino)-thiazol-4-yl]-benzoic acid (Example
8.62)
[0295] 4-(2-Cyclopropylamino-thiazol-4-yl)-benzoic acid (1.98
mmol), methyliodide (4.36 mmol) and potassium carbonate were mixed
in DMF (20 mL) and stirred for 72 hours at room temperature. The
mixture was concentrated to dryness and partitioned between
dichloromethane and water. The organic layer was dried (MgSO4) and
concentrated to dryness. This solid was mixed with THF (4 mL),
methanol (2 mL) and 1N LiOH (3 mmol) and heated to 50.degree. C.
for 1 hour. The mixture was then cooled to room temperature and 1N
HCl was added until pH 4. The mixture was concentrated in vacuo,
then the obtained residue was redissolved in
dichloromethane-methanol and concentrated onto silica. Flash
chromatography of the residue (silica gel,
dichloromethane-methanol) gave the title compound as an off-white
solid (0.1 g), m/z=275.0 in MS ES+, which was characterised by hplc
and MS.
4-[2-(1-Methyl-pyrrolidin-3-yl)-thiazol-5-yl]-benzoic acid (Example
8.63)
[0296] 3-Thiocarbamoyl-pyrrolidine-1-carboxylic acid tert-butyl
ester (2.47 mmol) 4-(2-Bromo-acetyl)-benzoic acid (2.47 mmol) were
mixed in THF (12 mL). After stirring at room temperature for 5
minutes the mixture was heated to 80.degree. C. for 1 hour. The
mixture was then cooled to room temperature and filtered. The solid
was washed with a small amount of diethylether and dried. m/z=304.1
in MS ES+. This solid was then mixed in
dichloromethane-trifluoroacetic acid (2:1) and kept at room
temperature for 20 minutes. The mixture was concentrated to near
dryness and the concentrated once from dichloromethane and once
from 1N HCl in diethylether. The remaining solid was mixed with
acetic acid (0.5 mL), methanol (3 mL) and tetrahydrofurane (4.5 mL)
and formaldehyde (aq. 37%, 300 mL) and polystyrene bound
cyanoborohydride (2.36 mmol/g, 900 mg) was added. The slurry was
then agitated for 16 hours at room temperature. The slurry was then
filtered and the resin washed with methanol (2 mL). The solution
was concentrated to dryness in vacuo. m/z=289.0 in MS ES+, which
was characterized by hplc and MS and used in the next step without
any further purification.
2-(1-methylpiperazine-4-yl)-6-(4-carboxyphen-1-yl)-pyridine
hydrochloride (Example 8.64)
[0297] 2.6-dibromopyridine (11.8 g, 50 mmol) was dissolved in
dimethylformamide (50 ml) and 1-methylpiperazine (5.0 g, 50 mmol)
and sodium iodide (0.6 g) was added. The solution was heated to
80.degree. C. for 30 minutes, then allowed to reach room
temperature and diluted with ethyl acetate and water. The water
layer was carefully extracted and the organic layers were
collected, dried (Na.sub.2SO.sub.4) and concentrated. Flash
chromatography of the residue on silica-gel (packed with ethyl
acetate) using ethyl acetate-methanol-triethylamine 20:2:1 as the
eluant. Pure fractions were collected and concentrated. 1.54 g of
the residue was dissolved in dimethoxymethane (48 ml) and
tetrakistriphenylphosphine palladium(0) (5.0 g) was added. The
solution was degassed and stirred for 15 minutes under N2.
4-ethoxycarbonylphenylboronic acid (1.16 g) was added followed by
36 ml aq. 1M sodium hydrogen carbonate solution. The solution was
degassed one more time and heated to reflux and stirred for 12
hours. The solution was filtered and the filtercake was carefully
extracted with ethyl acetate and dimethoxymethane. The extracts
were evaporated and purified by flashchromathography on silica-gel
(packed with ethyl acetate) using ethyl
acetate-methanol-triethylamine 20:2:1 as the eluant. Pure fractions
were collected and concentrated. The residue was dissolved in 30 ml
concentrated hydrochloric acid and was refluxed for 12 hours. The
solution was evaporaded to yield the title compound as a solid.
.sup.1H-NMR (400 MHz, DMSO-d.sub.6) .delta. 2.7 (3H, m) 3.3 (4H, m)
4.5 (4H, m) 7.0 (1H, m) 7.4 (1H, m) 7.8 (1H, m) 8.0 (1H, m) 8.15
(1H, m) 11.5 (1H, bs).
4-(6-Morpholin-4-yl-pyridin-2-yl)-benzoic acid hydrochloride
(Example 8.65)
[0298] 2.6-dibromopyridine (2.0 g) was dissolved in
dimethoxymethane and morpholine (4.0 ml) and sodium iodide (0.3 g)
was added. The solution was heated to reflux for 1 hour, then
allowed to reach room temperature. The obtained solution was
diluted with ethyl acetate, washed with water, then dried
(Na.sub.2SO.sub.4), filtered and concentrated. Flash chromatography
of the residue using stepwise gradient elution (ethyl acetate in
hexane 20-33%). Pure fractions were concentrated and then subjected
to Suzuki coupling as described in example 8.64, then purified by
flash chromatography as described above. Pure fractions where
collected and concentrated, then the residue was dissolved in 30 ml
concentrated hydrochloric acid and was refluxed for 1 hour. The
obtained solution was evaporated to yield the title compound as a
solid. 1 H-NMR (400 MHz, DMSO-d.sub.6) .delta. 3.6 (4H, m) 3.7 (4H,
m) 6.9 (1H, m) 7.3 (1H, m) 7.7 (1H,M) 7.9 (2H, m) 8.1 (2H, m).
Example 9
Fluid phase synthesis of
N-[(1S)-1-(3aS,6S,6aS)-6-Fluoro-3-oxo-hexahydro-furo[3,2-b]pyrrole-4-carb-
onyl)-3-methyl-butyl]-4-[5-methyl-2-(4-methyl-piperazin-1-yl)-thiazol-4-yl-
]-benzamide
##STR00228##
[0299] a)
[(1S)-1-((3R,3aR,6S,6aS)-6-Fluoro-3-hydroxy-hexahydro-furo[3,2-b-
]pyrrole-4-carbonyl)-3-methyl-butyl]-carbamic acid benzyl ester
(2')
[0300]
(3R,3aR,6S,6aS)-6-Fluoro-3-hydroxy-hexahydro-furo[3,2-b]pyrrole-4-c-
arboxylic acid tert-butyl ester (1') (20.24 mmol) was dissolved in
4M HCl in 1,4-dioxane, and stirred at room temperature for 1 h. The
solvent was then removed under vacuum, and the residue was
suspended in dichloromethane (50 ml), and treated with Cbz-Leu-OH
(20.24 mmol), WSC HCl (22.26 mmol), HOBt (22.26 mmol) and NMM
(40.48 mmol). The reaction mixture was stirred at room temperature
overnight, then washed with saturated aqueous NaHCO.sub.3, dried
and concentrated. The residue was purified by column chromatography
(ethyl acetate-hexanes 1:1, Rf 0.23) to afford compound 2 (15.62
mmol, 77%). MS (ES) m/z 395 (100%, [M+H].sup.+).
b)
[(1S)-1-((3aS,6S,6aS)-6-Fluoro-3-oxo-hexahydro-furo[3,2-b]pyrrole-4-car-
bonyl)-3-methyl-butyl]-carbamic acid benzyl ester (3')
[0301] A solution of compound 2' (15.61 mmol) in dichloromethane
(70 ml) was treated with Dess-Martin periodinone (15.61 mmol), and
the reaction mixture was stirred at room temperature overnight. The
solution was then washed with saturated aqueous NaHCO.sub.3, dried
and concentrated, and the residue was purified by column
chromatography (ethyl acetate-hexanes 1:1, Rf 0.37) to afford
compound 3 (9.38 mmol, 60%). MS (ES) m/z 393 (15%, [M+H].sup.+),
411 (100%, [MH+H.sub.2O].sup.+).
c)
[(1S)-1-((3aS,6S,6aS)-6-Fluoro-3,3-dimethoxy-hexahydro-furo[3,2-b]pyrro-
le-4-carbonyl)-3-methyl-butyl]-carbamic acid benzyl ester (4')
[0302] A solution of compound 3' (8.49 mmol) in anhydrous methanol
(50 ml) was treated with 1,1,2-trimethylorthoformate (24 ml) and
p-TsOH (catalytic amount), and stirred at 60.degree. C. for 3 h.
The reaction mixture was then cooled down to room temperature, the
solvent was removed under vacuum and the residue was purified by
column chromatography to afford compound 4' (7.42 mmol, 87%). MS
(ES) m/z 439 (100%, [M+H].sup.+).
d)
N-[(1S)-1-((3aS,6S,6aS)-6-Fluoro-3,3-dimethoxy-hexahydro-furo[3,2-b]pyr-
role-4-carbonyl)-3-methyl-butyl]-4[5-methyl-2-(4-methyl-piperazin-1-yl)-th-
iazol-4-yl]-benzamide (5')
[0303] Compound 4' (0.625 mmol) was dissolved in ethanol (15 ml),
and treated with a catalytic amount of Pd (10% wt Pd in carbon).
The reaction was stirred under hydrogen atmosphere for 3-4 h. The
reaction mixture was then filtered through a celite cake, and the
cake was washed with ethanol, the organic extracts were combined
and concentrated under vacuum. The residue was then dissolved in
dichloromethane (15 ml) and treated with
4-[5-Methyl-2-(4-methyl-piperazin-1-yl)-thiazol-4-yl]-benzoic acid
(0.60 mmol), WSC HCl (0.625 mmol) and HOBt (0.625 mmol). The
reaction mixture was monitored by HPLC. When the reaction had
finished (4 h) the organic solution was washed with saturated
aqueous NaHCO.sub.3, dried and concentrated, and the residue was
purified by preparative HPLC to afford compound 5 (0.30 mmol, 50%).
MS (ES) m/z 604 (100% [M+H].sup.+).
e) N-[(1S)-1-((3aS,
6S,6aS)-6-Fluoro-3-oxo-hexahydro-furo[3,2-b]pyrrole-4-carbonyl)-3-methyl--
butyl]-4-[5-methyl-2-(4-methyl-piperazin-1-yl)-thiazol-4-yl]-benzamide
(6')
[0304] Compound 5' (0.21 mmol) was dissolved in neat
trifluoroacetic acid (2 ml) and stirred at room temperature. The
reaction was monitored closely by HPLC, to avoid cleaveage of the
tertiary amide. As soon as the starting material disappeared (3 h
45 min) the TFA was removed under a stream of nitrogen, and the
residue was partitioned between ethyl acetate and saturated aqueous
NaHCO.sub.3, the organic extracts were dried and concentrated under
vacuum, and the residue was dissolved in acetonitrile-water 1:1 (2
ml) and freeze-dried overnight to afford compound 6' as a white
solid (0.20 mmol, 94%). MS (ES) m/z 558 (10%, [M+H].sup.+), 576
(100%, [MH+H.sub.2O].sup.+).
Biological Examples
Determination of Cathepsin K Proteolytic Catalytic Activity
[0305] Convenient assays for cathepsin K are carried out using
human recombinant enzyme, such as that described in PDB.
ID BC016058 standard; mRNA; HUM; 1699 BP. DE Homo sapiens cathepsin
K (pycnodysostosis), mRNA (cDNA clone MGC:23107
RX MEDLINE; RX PUBMED; 12477932.
DR RZPD; IRALp962G1234.
DR SWISS-PROT; P43235;
[0306] The recombinant cathepsin K can be expressed in a variety of
commercially available expression systems including E coli, Pichia
and Baculovirus systems. The purified enzyme is activated by
removal of the prosequence by conventional methods.
[0307] Standard assay conditions for the determination of kinetic
constants used a fluorogenic peptide substrate, typically
H-D-Ala-Leu-Lys-AMC, and were determined in either 100 mM Mes/Tris,
pH 7.0 containing 1 mM EDTA and 10 mM 2-mercaptoethanol or 100 mMNa
phosphate, imM EDTA, 0.1% PEG4000 pH 6.5 or 100 mM Na acetate, pH
5.5 containing 5 mM EDTA and 20 mM cysteine, in each case
optionally with 1M DTT as stabiliser. The enzyme concentration used
was 5 nM. The stock substrate solution was prepared at 10 mM in
DMSO. Screens were carried out at a fixed substrate concentration
of 60 .mu.M and detailed kinetic studies with doubling dilutions of
substrate from 250 .mu.M. The total DMSO concentration in the assay
was kept below 3%. All assays were conducted at ambient
temperature. Product fluorescence (excitation at 390 nm, emission
at 460 nm) was monitored with a Labsystems Fluoroskan Ascent
fluorescent plate reader. Product progress curves were generated
over 15 minutes following generation of AMC product.
Inhibition Studies
[0308] Potential inhibitors are screened using the above assay with
variable concentrations of test compound. Reactions were initiated
by addition of enzyme to buffered solutions of substrate and
inhibitor. K.sub.i values were calculated according to equation
1
v 0 = VS K M ( 1 + I K i ) + S ( 1 ) ##EQU00001##
where v.sub.0 is the velocity of the reaction, V is the maximal
velocity, S is the concentration of substrate with Michaelis
constant of K.sub.M, and I is the concentration of inhibitor.
[0309] Compounds of the invention bearing the distinctive halogen
substituent in the P1 group were assayed against the closest
individualised compound of the abovementioned WO 02057270:
TABLE-US-00005 Compound Cathepsin K K.sup.i nM ##STR00229## 66*
##STR00230## 5.3
[0310] It will be apparent that introduction of at least one
halogen atom to P1, according to the invention has surprisingly
resulted in a 10 fold increase in potency. [0311] Note that the Ki
indicated in WO 02057270 for the prior art compound is the less
potent 0.1 micromolar, whereas the above trials reflect accurate
side by side trials in the same assay system.
Abbreviations
[0312] DMF dimethylformamide DCM dichloromethane TBDMS
tert-butyldimethylsilyl RT room temperature THF tetrahydrofuran Ac
acetyl TLC thin layer chromatography DMAP dimethylaminopyridine
EtOAc ethyl acetate
[0313] Throughout the specification and the claims which follow,
unless the context requires otherwise, the word `comprise`, and
variations such as `comprises` and `comprising`, will be understood
to imply the inclusion of a stated integer, step, group of integers
or group of steps but not to the exclusion of any other integer,
step, group of integers or group of steps.
* * * * *