U.S. patent application number 12/625178 was filed with the patent office on 2010-03-18 for process for making trans-1-((1r,3s)-6-chloro-3-phenylindan-1-yl)-3,3-dimethylpiperazine.
This patent application is currently assigned to H. LUNDBECK A/S. Invention is credited to Peter Brosen, Allan Carsten Dahl, Christina Wohlk Nielsen, David Robin, Christina Suteu.
Application Number | 20100069676 12/625178 |
Document ID | / |
Family ID | 38323790 |
Filed Date | 2010-03-18 |
United States Patent
Application |
20100069676 |
Kind Code |
A1 |
Dahl; Allan Carsten ; et
al. |
March 18, 2010 |
PROCESS FOR MAKING
TRANS-1-((1R,3S)-6-CHLORO-3-PHENYLINDAN-1-YL)-3,3-DIMETHYLPIPERAZINE
Abstract
Described is a method for making the
trans-1-((1R,3S)-6-chloro-3-phenylindan-1-yl)-3,3-dimethylpiperazine
(formula I) and salts thereof and a similar method for making
4-((1R,3S)-6-chloro-3-phenylindan-1-yl)-1,2,2-trimethylpiperazine
(formula IX) and salts thereof, which method comprises conversion
of a compound of formula IVa to the compound of formula I or the
compound of formula IX, respectively. ##STR00001##
Inventors: |
Dahl; Allan Carsten; (Nyrup,
DK) ; Nielsen; Christina Wohlk; (Copenhagen, DK)
; Suteu; Christina; (Illkirch, FR) ; Robin;
David; (Strasbourg, FR) ; Brosen; Peter;
(Herlev, DK) |
Correspondence
Address: |
LUNDBECK RESEARCH USA, INC.;ATTENTION: STEPHEN G. KALINCHAK, LEGAL
215 COLLEGE ROAD
PARAMUS
NJ
07652
US
|
Assignee: |
H. LUNDBECK A/S
Valby-Copenhagen
DK
|
Family ID: |
38323790 |
Appl. No.: |
12/625178 |
Filed: |
November 24, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11816383 |
Feb 11, 2008 |
|
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PCT/DK2006/000086 |
Feb 14, 2006 |
|
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12625178 |
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60653428 |
Feb 16, 2005 |
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Current U.S.
Class: |
568/327 |
Current CPC
Class: |
A61P 25/36 20180101;
A61P 25/18 20180101; C07D 295/073 20130101; C07C 29/143 20130101;
C07C 25/22 20130101; A61P 25/30 20180101; C07C 49/697 20130101;
C07C 45/78 20130101; A61P 25/24 20180101; A61P 25/32 20180101; A61P
25/20 20180101; C07C 45/67 20130101; C07C 2602/08 20170501; A61P
25/06 20180101; C07C 17/16 20130101; C07B 2200/07 20130101; C07C
45/292 20130101; C07C 17/16 20130101; C07C 25/22 20130101; C07C
45/292 20130101; C07C 49/697 20130101; C07C 45/67 20130101; C07C
49/697 20130101; C07C 45/78 20130101; C07C 49/697 20130101; C07C
29/143 20130101; C07C 35/52 20130101 |
Class at
Publication: |
568/327 |
International
Class: |
C07C 49/537 20060101
C07C049/537 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 16, 2005 |
DK |
DK PA 2005 00237 |
Claims
1-32. (canceled)
33. A compound (IVa) having a structure as follow: ##STR00013##
34. A compound (IVb) having a structure as follow: ##STR00014##
35. The compound as defined in claim 33, wherein the compound is
substantially pure.
36-58. (canceled)
59. The compound of claim 34, wherein the compound is substantially
pure.
Description
[0001] The present invention relates to a process for making
trans-1-((1R,3S)-6-chloro-3-phenylindan-1-yl)-3,3-dimethylpiperazine
(Compound I) and salts thereof.
BACKGROUND OF THE INVENTION
[0002] The compound, which is the subject of the present invention
(Compound I,
trans-1-((1R,3S)-6-chloro-3-phenylindan-1-yl)-3,3-dimethylpiperazine)
has the general formula (I).
##STR00002##
[0003] Compound I and salts thereof, including a fumarate and
maleate salt thereof, and the medical uses thereof, e.g. in
schizophrenia or other diseases involving psychotic symptoms, are
described in PCT/DK04/000546 (WO05/016901).
[0004] As described in PCT/DK04/000546 the inventors have found
that Compound I displays high affinity for dopamine (DA) D1
receptors, DA D2 receptors and for alfa1 adrenoceptors.
Furthermore, Compound I was found to be an antagonist at dopamine
D1 and D2 receptors, and at serotonin 5-HT2a receptors. As further
described in PCT/DK04/000546, Compound I is a relatively weak
inhibitor of CYP2D6 (i.e. reduced potential for drug to drug
interaction) and has a relatively low effect on the QT interval in
a rabbit model (i.e. reduced potential for introducing drug-induced
QT interval prolongation and appearance of fatal cardiac
arrhythmias, torsade de pointes (TdP), in humans). Additionally,
the 5-HT.sub.2 antagonistic activity of Compound I suggests that
Compound I may have a relatively low risk of extrapyramidal side
effects.
[0005] The properties outlined above, e.g. binding assays
(including alfa-1, DA D1 or D2 receptors), efficacy assays
(including DA D1 or D2, or serotonin 5-HT.sub.2A receptors), CYP2D6
inhibition and QT-interval may be determined as described in
PCT/DK04/000546, cf. in particular the "Example" section page 19-24
in the application text as filed for
PCT/DK04/000546..quadrature.
[0006] Further, the inventors have found that Compound I did not
induce dystonia when tested in pigs sensitized to haloperidol,
indicating that Compound I does not possess EPS (extrapyramidal
symptoms) response/liability in humans.
[0007] PCT/DK04/000546 describes the following medical uses of
Compound I: a disease in the central nervous system, including
psychosis, in particular schizophrenia (e.g. positive, negative,
and/or depressive symptoms) or other diseases involving psychotic
symptoms, such as, e.g., Schizophrenia, Schizophreniform Disorder,
Schizoaffective Disorder, Delusional Disorder, Brief Psychotic
Disorder, Shared Psychotic Disorder as well other psychotic
disorders or diseases that present with psychotic symptoms, e.g.
mania in bipolar disorder. Also described is the use of Compound I
for treatment of anxiety disorders, affective disorders including
depression, sleep disturbances, migraine, neuroleptic-induced
parkinsonism, or cocaine abuse, nicotine abuse, alcohol abuse and
other abuse disorders.
[0008] As indicated in PCT/DK04/000546 a group of compounds
structurally related to Compound I, i.e. trans isomers of
3-aryl-1-(1-piperazinyl)indanes substituted in the 2- and/or
3-position of the piperazine ring, has been described in EP 638
073; Bogeso et al. in J. Med. Chem., 1995, 38, 4380-4392 and Klaus
P. Bogeso in "Drug Hunting, the Medicinal Chemistry of
1-piperazino-3-phenylindans and Related Compounds", 1998, ISBN
87-88085-10-41. For example, an enantiomeric pure compound
corresponding to formula (I) but differing in that it has an
N-methyl group instead of an N-hydrogen on the piperazine has been
disclosed in Bogeso et al. in J. Med. Chem., 1995, 38, 4380-4392,
see table 5, compound (-)-38.
[0009] None of the above references apart from PCT/DK04/000546
disclose the specific enantiomeric form above (Compound I) or
medical use thereof. The trans isomer in the form of the racemate
of Compound I is only indirectly disclosed as an intermediate in
the synthesis of compound 38 in Bogeso et al. in J. Med. Chem.,
1995, 38, 4380-4392 while medical use of Compound I or its
corresponding racemate is not described. Compound I as an
intermediate is disclosed in PCT/DK04/000545 (WO05/016900).
DETAILED DESCRIPTION OF THE INVENTION
[0010] The present invention in one aspect relates to a new process
for the preparation of Compound I wherein the chirality is
introduced earlier in the manufacturing process as compared to the
process described in PCT/DK04/000546. The introduction of the
chirality one step earlier is an advantage because the following
step becomes more efficient in terms of e.g. volume yield, and
consumption of reagents and solvents and production of less waste.
In PCT/DK04/000546, the chirality is introduced by resolving the
racemic intermediate V below, either enzymatically or by chiral
HPLC. The present inventors have now developed a route of synthesis
in which the enantiomer of formula (I) is obtained via a sequence
starting from enantiomeric pure IV, i.e. Compound IVa
((S)-6-chloro-3-phenylindan-1-one, see below). Thus, in this
process, the intermediate of formula IV is resolved, e.g. by chiral
chromatography, to obtain the enantiomer of formula IVa.
[0011] Furthermore, the present inventors have developed a method
for the racemisation of the undesired enantiomer (Compound IVb, see
below), which then can be reused in the resolution. This has a
tremendous impact on the efficiency of the whole synthesis, as the
efficiency of the steps before the resolution is increased as well
as the subsequent steps.
[0012] Accordingly, the enantiomer of formula (I) may be obtained
by a process involving the following steps:
##STR00003##
[0013] Benzyl cyanide is reacted with 2,5-dichlorobenzonitril in
the presence of a base, suitably potassium tert-butoxide (t-BuOK)
in a suitable solvent such as 1,2-dimethoxyethane (DME), further
reaction with methyl chloro acetate (MCA) leads to spontaneous ring
closure and one pot formation of the compound of formula (II).
[0014] The compound of formula (II) is then subjected to acidic
hydrolysis to form a compound of formula (III), suitably by heating
in a mixture of acetic acid, sulphuric acid and water, and
thereafter decarboxylation, e.g., by heating the compound of
formula (III) in a suitable solvent, such as toluene with triethyl
amine or N-methylpyrrolidin-2-one (NMP), to form a compound of
formula (IV).
##STR00004##
[0015] The compound of formula (IV) is resolved to achieve the
desired enantiomer (formula IVa) for the further synthesis of
Compound I, and the undesired enantiomer (formula IVb) which may be
subjected to racemisation and recycling:
##STR00005##
[0016] The resolution of IV may, e.g., be performed using chiral
chromatography, preferable liquid chromatography, or sub- or
supercritical fluid chromatography.
[0017] Chiral liquid chromatography may, e.g., be performed on a
chiral stationary phase, suitably on a column of silica gel with an
immobilized chiral polymer, or preferably on a column of silica gel
coated with a chiral polymer, e.g. a modified cellulose, or a
modified amylose, such as amylose tris
[(S)-.alpha.-methylbenzylcarbamate], preferably a column of silica
gel coated with amylose tris
[(S)-.alpha.-methylbenzylcarbamate].
[0018] A suitable solvent is used for the chiral liquid
chromatography, such as, e.g. an alcohol (preferably a
C.sub.1-4-alcohol), a nitrile, an ether, or an alkane (preferably a
C.sub.5-10-alkane), or mixtures thereof, suitably ethanol,
methanol, iso-propanol, acetonitrile, methyl tert-butyl ether or
n-heptane or mixtures thereof, preferably ethanol or n-heptane or a
mixture thereof. Acidic or basic modifiers can be added to the
eluent, e.g. formic acid, acetic acid, trifluoroacetic acid,
triethylamine, or N,N-diethylamine.
[0019] Sub- or supercritical fluid chromatography may, e.g., be
performed on a chiral stationary phase, suitably on a column of
silica gel with an immobilized chiral polymer, or on a column of
silica gel coated with a chiral polymer, e.g. a modified amylose,
such as amylose tris [(S)-.alpha.-methylbenzylcarbamate], or
preferably amylose tris (3,5-dimethylphenylcarbamate), most
preferably amylose tris (3,5-dimethylphenylcarbamate) coated on
silica gel, or a modified cellulose, such as cellulose tris
(4-methylbenzoate), or preferable cellulose tris
(3,5-dimethylphenylcarbamate), most preferably cellulose tris
(3,5-dimethylphenylcarbamate) coated on silica gel. Other types of
chiral stationary phases may be used, e.g. the Pirkle type columns,
suitable on a column of silica gel with covalently bonded
3,5-dinitrobenzoyl tetrahydrophenanthrene amine.
[0020] Sub- or supercritical carbon dioxide, suitable supercritical
carbon dioxide, containing a modifier may be used as eluent for the
sub- or supercritical fluid chromatography. The modifier is
selected from the lower alcohols such as methanol, ethanol,
propanol and isopropanol, or e.g. acetonitril may be used. An
amine, such as diethylamine, optionally 0.1% diethylamine,
triethylamine, propylamine, and dimethyl iso-propyl amine, and
optionally an acid, such as formic acid, acetic acid and
trifluoroacetic acid may be added.
[0021] In a further embodiment of the invention the modifier is
selected from the lower alcohols such as methanol, ethanol,
propanol and isopropanol, or e.g. acetonitril may be used, as long
as the modifier is compatible with the column.
[0022] The chiral chromatography can be scaled up using suitable
technologies, e.g. simulated moving bed technology (SMB), or sub-
or supercritical fluid technology (cf. G. B. Cox (ed.) Preparative
Enantioselective Chromatography, Blackwell Publishing Ltd., Oxford,
UK, 2005).
[0023] The compound of formula (IVa) is then reduced e.g. with a
complex metal hydride, such as borohydride, suitably with sodium
borohydride (NaBH.sub.4) or such as lithium aluminiumhydride, in a
solvent, such as an alcohol (e.g. a C.sub.1-5-alcohol), e.g.
ethanol or iso-propanol, and preferably at a temperature in the
range of about -30.degree. to +30.degree. C., e.g. below 30.degree.
C., below 20.degree. C., below 10.degree. C., or preferably below
5.degree. C., to form a compound of formula (Va) with cis
configuration:
##STR00006##
[0024] The alcohol group of the cis-alcohol of formula (Va) is
converted to a suitable leaving group, such as, e.g., a halogen,
e.g. Cl or Br, preferably Cl, or a sulphonate, e.g. mesylate
(methansulfonylate) or tosylate (4-toluenesulfonylate), suitably by
reaction with an agent, such as thionyl chloride, mesyl
(methansulfonyl) chloride or tosyl (4-toluenesulfonyl) chloride, in
an inert solvent, e.g. an ether, suitably tetrahydrofuran. The
resulting compound has formula (VI), where LG is the leaving
group:
##STR00007##
[0025] In a preferred embodiment, LG is Cl, i.e. the cis-chloride
of formula (VIa):
##STR00008##
[0026] Compound VI, e.g. with LG as chloro, is then reacted with
2,2-dimethylpiperazine in a suitable solvent, e.g. a ketone such
as, e.g., methyl isobutyl ketone or methyl ethyl ketone, preferably
methyl isobutyl ketone in the presence of a base, such as e.g.,
potassium carbonate, to obtain Compound I.
[0027] Alternatively, the piperazine part of the molecule may be
introduced by reacting Compound VI with a compound of formula (VII)
below, where PG is a protecting group, such as, but not restricted
to, e.g. phenylmethoxycarbonyl (often called Cbz or Z),
tert-butyloxycarbonyl (often called BOC), ethoxycarbonyl, or
benzyl, thereby obtaining the compound of formula (VIII) below.
Compound VIII is subsequently deprotected to afford Compound I.
##STR00009##
[0028] A further embodiment of the invention relates to a method
for the manufacturing of a compound [Compound IX:
4-((1R,3S)-6-chloro-3-phenylindan-1-yl)-1,2,2-trimethylpiperazine]
having the following formula (IX) or a salt thereof:
##STR00010##
which method comprises: [0029] (i) manufacturing Compound I by a
method of the present invention, i.e. in particular from Compound
IVa; and [0030] (ii) converting Compound I into Compound IX,
preferably by methylating the secondary amine functionality,
suitably by reductive alkylation using suitable agents, such as,
e.g., formaldehyde, paraformaldehyde, trioxane, or diethoxy methane
(DEM).
[0031] The term reductive alkylation refers to the above-mentioned
reagents in combination with a reductive agent, such as formic
acid.
[0032] Thus, further embodiment of the invention relates to the
methods as described herein for the manufacturing of Compound I,
wherein Compound I is "replaced" by Compound IX.
[0033] Compound IX is described generically in EP 638 073 while the
enantiomer of formula (IX) has been described by Bogeso et al. in
J. Med. Chem., 1995, 38, page 4380-4392, in the form of the
fumarate salt, see table 5, compound (-)-38. Compound I.times. and
a method for manufacturing Compound I.times. from Compound I, and
salts of Compound IX (in particular a crystalline succinate salt
and a crystalline malonate salt) are further described in
PCT/DK2004/00545.
[0034] As indicated above the invention also relates to a method
for the manufacturing of Compound I or Compound IX as described
herein wherein Compound IVb is recycled such that it can be used
for the synthesis of Compound I or Compound IX, respectively, see
also the illustration below.
##STR00011##
[0035] Surprisingly, the racemisation of compound IVb can be
achieved using different types of bases, e.g. an amide, preferably
a dialkylamide, e.g. but not limited to lithium diethylamide,
lithium diisopropylamide, lithium tetramethylpiperidide, suitable
lithium diisopropylamide (LDA), or a metal bis-silylamide, e.g.
alkali bis(trimethylsilyl)amide, or an metal alkoxide, e.g. but not
limited to metal methoxide, metal ethoxide, metal tert-butoxide,
suitably alkali alkoxide, preferably potassium alkoxide, must
preferably potassium tert-butoxide, or an alkyl metal, suitable an
alkyl lithium, preferably butyl lithium or tent-butyl lithium.
After quenching the reaction mixture, the racemic ketone IV can be
isolated.
[0036] The racemisation can be achieved using two different bases
as well; again, different types of non nucleophillic bases can by
used as "the former base" (base 1), e.g. an amide, preferably a
dialkylamide, e.g. but not limited to lithium diethylamide, lithium
diisopropylamide, lithium tetramethylpiperidide, suitable lithium
diisopropylamide (LDA), or a metal bis-silylamide, e.g. lithium
bis-silylamide, suitably lithium bis(trimethylsilyl)amide, or an
metal alkoxide, e.g. but not limited to metal methoxide, metal
ethoxide, metal tert-butoxide, suitably alkali alkoxide, preferably
lithium alkoxide, must preferably lithium tert-butoxide. After the
former base (base 1) have been mixed with the ketone, "the latter
base" (base 2) is added. As with the former base, different types
of bases can be used; e.g. an amide, preferably a dialkylamide,
e.g. but not limited to lithium diethylamide, lithium
diisopropylamide, lithium tetramethylpiperidide, suitable lithium
diisopropylamide (LDA), or a metal bis-silylamide, e.g. alkali
bis(trimethylsilyl)amide, or an metal alkoxide, e.g. but not
limited to metal methoxide, metal ethoxide, metal tert-butoxide,
suitably alkali alkoxide, preferably potassium alkoxide, must
preferably potassium tert-butoxide, or an alkyl metal, suitable an
alkyl lithium, preferably butyl lithium or tert-butyl lithium.
[0037] Furthermore, racemisation can be obtained using two or more
different bases by adding them all from the very start, preferable
by adding two different bases from the very start.
[0038] In a further embodiment of the invention the racemisation
can achieved by using a nucleophillic base.
[0039] Alternatively, the racemic alcohol V can be resolved by
chiral chromatography as described in PCT/DK04/000546, to obtain Va
for the synthesis of Compound I, and Vb, which can be racemerised
and reused in the resolution as indicated in the figure below. The
racemisation of Vb is obtained by oxidation of Vb to IVb, e.g. by
using pyridinium chlorochromate (PCC), racemisation of IVb to IV as
described above, and then reduction of IV to V in the usual way, as
described above.
##STR00012##
[0040] When studying the racemisation on a 10 g scale, an impurity
as a by product can be detected by LC-MS (liquid
chromatography-mass spectroscopy); analytic data suggest that the
impurity is a dimer of IV and/or the enantiomers IVa and IVb. The
analytical data furthermore indicates, that the dimer can eliminate
water, depending on the work up procedure. Laborious work has
shown, that the formation of the dimer can be suppressed
appreciably by carefully selecting the conditions for the
racemisation, and the content of the dimer in the product can by
further reduced by recrystallising the product from a suitably
solvent, e.g. an alcohol, preferably ethanol or 2-propanol.
[0041] During the synthesis of Compound I some cis diastereoisomer
of Compound I (i.e.
1-((1S,3S)-6-chloro-3-phenylindan-1-yl)-3,3-dimethylpiperazine) may
be formed as an impurity in the final product. This impurity is due
mainly to the formation of some of the trans form of (VI) (e.g.
(1S,3R)-3,5-dichloro-1-phenylindan when LG is Cl) in the step where
Compound VI is formed. Therefore, the impurity can be minimized by
crystallisation of the desired cis form of Compound VI, from the
mixture of trans and cis (VI); in the case where LG is Cl in
Compound VI this can be done by stirring the mixture with a
suitable solvent, e.g. an alkane (C.sub.5-10-alkane), such as
heptane, whereby the desired cis form of VI precipitates and the
undesired trans form of Compound VI goes into solution. The desired
cis form of Compound VI (e.g. when LG is Cl) is isolated, e.g., by
filtration, and preferably washed with the solvent in question and
dried.
[0042] The cis form of Compound I may also be removed by
precipitation of a suitable salt of Compound I, e.g. a
hydrochloride salt or a salt of an organic acid, such as an organic
diacid, suitably a fumarate salt or a maleate salt of the compound
of formula (I), optionally followed by one or more
re-crystallisations e.g. as described in PCT/DK2004/000546.
[0043] The cis form of Compound I may also be removed by isolating
Compound I as the free base from a suitable solvent.
[0044] The invention in further aspects also relates to the
intermediates as described herein for the synthesis of the Compound
I, in particular the intermediates IVa and IVb. In this context is
understood when specifying the stereoisomeric form, that the
stereoisomer is the main constituent. In particular, when
specifying the enantiomeric form, then the compound has an
enantiomeric excess of the enantiomer in question.
[0045] Accordingly, one embodiment of the invention relates to the
compound of formula (IVa), preferably having an enantiomeric excess
of at least 60% (60% enantiomeric excess means that the ratio of
Compound IVa to its enantiomer is 80:20 in the mixture in
question), at least 70%, at least 80%, at least 85%, at least 90%,
at least 96%, preferably at least 98%. One embodiment relates to
substantially pure Compound IVa.
[0046] A further embodiment of the invention relates to the
compound of formula (IVb), preferably having an enantiomeric excess
of at least 60%.
[0047] The invention in a further aspect relates to Compound I or a
salt thereof (e.g. a HCl, a fumarate or a maleate salt thereof)
obtained by a method of the invention, and the medical use thereof,
in particular for the medical indication as disclosed herein, e.g.
as an antipsychotic, such as for schizophrenia. Also within the
invention are a pharmaceutical composition of Compound I or salt
thereof obtained by a method of the invention.
[0048] In the present context, in particular for the pharmaceutical
uses of Compound I, it is understood that when specifying the
enantiomer form as done in formula (I), then the compound is
preferably relatively stereochemically pure, preferably the
enantiomeric excess is at least 60%, at least 70%, and more
preferably at least 80% (80% enantiomeric excess means that the
ratio of Ito its enantiomer is 90:10 in the mixture in question) at
least 90%, at least 96%, or preferably at least 98%. In a preferred
embodiment, the diastereomeric excess of Compound I is at least 90%
(90% diastereomeric purity means the ratio of Compound I to
cis-1-((1S,3S)-6-chloro-3-phenylindan-1-yl)-3,3-dimethylpiperazine
is 95:5), at least 95%, at least 97%, or at least 98%.
[0049] Accordingly, the process of the invention may comprise a
step whereby Compound I or a salt thereof is formulated into a
pharmaceutical composition. The compound, salt or composition of
Compound I may be administered in any suitable way e.g. orally,
buccal, sublingual or parenterally, and the compound or salt may be
presented in any suitable form for such administration, e.g. in the
form of tablets, capsules, powders, syrups or solutions or
dispersions for injection. In one embodiment, the compound or salt
of the invention are administered in the form of a solid
pharmaceutical entity, suitably as a tablet or a capsule.
[0050] Methods for the preparation of solid pharmaceutical
preparations are well known in the art. Tablets may thus be
prepared by mixing the active ingredient with ordinary adjuvants,
fillers and diluents and subsequently compressing the mixture in a
convenient tabletting machine. Examples of adjuvants, fillers and
diluents comprise corn starch, lactose, talcum, magnesium stearate,
gelatine, lactose, gums, and the like. Any other adjuvant or
additive such as colourings, aroma, preservatives, etc. may also be
used provided that they are compatible with the active
ingredients.
[0051] Solutions for injections may be prepared by dissolving a
salt of the invention and possible additives in a part of the
solvent for injection, preferably sterile water, adjusting the
solution to desired volume, sterilisation of the solution and
filling in suitable ampules or vials. Any suitable additive
conventionally used in the art may be added, such as tonicity
agents, preservatives, antioxidants, solubilising agents etc.
[0052] The daily dose of the compound of formula (I) above,
calculated as the free base, is suitably between 1.0 and 160
mg/day, more suitable between 1 and 100 mg, e.g. preferably between
2 and 55 mg.
[0053] The term "treatment" as used herein in connection with a
disease or disorders includes also prevention as the case may
be.
[0054] The invention will be illustrated in the following
non-limiting examples.
EXAMPLES
Analytical Methods
[0055] The enantiomeric excess of compounds (IV), (IVa), and (IVb)
is determined by supercritical fluid chromatography using a Gilson
SF3 Supercritical Fluid Chromatography System, detection is
performed using a Gilson UV/VIS-831 detector at 254 nm. Either a
CHIRALPAK.RTM. AD-H column, 0.46 cm ID.times.25 cm L, at room
temperature is used under the following conditions: Eluent: Ethanol
with 0.1% diethylamine is used at modifier (30%), the flow is 3
ml/min, and the pressure is 200 bar. The retention time of the two
enantiomers are 2.36 min. (IVa) and 2.99 min. (IVb). Or a
CHIRALCEL.RTM. OD-H column, 0.46 cm ID.times.25 cm L, at room
temperature is used under the following conditions: Eluent: Ethanol
(30%) is used as modifier, the flow is 4 ml/min, and the pressure
is 200 bar.
[0056] The enantiomeric excess of compound (Va) in Example 8 is
determined by supercritical fluid chromatography using a Gilson SF3
Supercritical Fluid Chromatography System with a CHIRALPAK.RTM.
AD-H column, 0.46 cm ID.times.25 cm L, at room temperature. Eluent:
Ethanol with 0.1% diethylamine is used at modifier (30%), the flow
is 3 ml/min, and the pressure is 200 bar. Detection is performed
using a Gilson UV/VIS-831 detector at 254 nm. The retention time of
the two enantiomers are 2.41 min. (Va) and 3.06 min. (Vb). The
enantiomeric excess of compound (Va) in Example 1a is determined by
chiral HPLC using a CHIRALCEL.RTM. OD column, 0.46 cm ID.times.25
cm L, 10 .mu.m at 40.degree. C. n-Hexan/ethanol 95:5 (vol/vol) is
used as mobile phase at a flow rate of 1.0 ml/min, detection is
performed using a UV detector at 220 nm.
[0057] The enantiomeric excess of compound (I) is determined by
fused silica capillary electrophoresis (CE) using the following
conditions: Capillar: 50 .mu.m ID.times.48.5 cm L, run buffer: 1.25
mM .beta. cyclo dextrin in 25 mM sodium dihydrogen phosphate, pH
1.5, voltage: 16 kV, temperature: 22.degree. C., injection: 40 mbar
for 4 seconds, detection: column diode array detection at 195 nm,
sample concentration: 500 .mu.g/ml. In this system, Compound I has
a retention time of approximately 10 min, and the other enantiomer
has a retention time of approximately 11 min.
[0058] The enantiomeric excess of compound (IX) is determined by
fused silica capillary electrophoresis (CE) using the following
conditions: Capillar: 50 .mu.m ID.times.64.5 cm L, run buffer: 3.0
mM .beta. cyclo dextrin and 10 mM hydroxypropyl .beta. cyclo
dextrin in 50 mM sodium dihydrogen phosphate, pH 1.5, voltage: 15
kV, temperature: 22.degree. C., injection: 40 mbar for 4 seconds,
detection: column diode array detection at 192 nm, sample
concentration: 100 .mu.g/ml. In this system, Compound IX has a
retention time of approximately 47 min, and the enantiomer has a
retention time of approximately 46 min. The other two
diastereoisomers
4-((1R,3R)-6-Chloro-3-phenyl-indan-1-yl)-1,2,2-trimethyl-piperazine
and
4-((1S,3S)-6-Chloro-3-phenyl-indan-1-yl)-1,2,2-trimethyl-piperazine
have retention times of approximately 49 min. and 52 min.
respectively.
[0059] .sup.1H NMR spectra are recorded at 500.13 MHz on a Bruker
Avance AV-500 instrument or a Bruker Avance DRX500 instrument, or
at 250.13 MHz on a Bruker Avance DPX-250 instrument or a Bruker AC
250 instrument. Chloroform (99.8% D) or dimethyl sulfoxide (99.8%
D) is used as solvents, and tetramethylsilane (TMS) is used as
internal reference standard.
[0060] The cis/trans ratio of Compound I and IX is determined using
H NMR as described in Bogeso et al., J. Med. Chem. 1995, 38,
4380-4392 (page 4388, right column). The cis/trans ratio of
compound VIa is determined by .sup.1H NMR in DMSO-d.sub.6, using
the integrals of the signal at 5.6 ppm for the cis isomer and the
signal at 5.75 ppm for the trans isomer, or by .sup.1H NMR in
chloroform, using the integrals of the signal at 5.3 ppm for the
cis isomer and the signal at 5.5 ppm for the trans isomer.
Generally, a content of approximately 1% of the undesired isomer
can be detected by NMR.
[0061] The Melting points are measured using Differential Scanning
Calorimetry (DSC). The equipment is a TA-Instruments DSC-Q1000 or a
TA-instruments DSC-2920 calibrated at 5.degree./min to give the
melting point as onset value. About 2 mg of sample is heated
5.degree./min in a loosely closed pan under nitrogen flow.
[0062] The elemental analysis is performed using a Vario El
analysator from Elementar build to measure C, H, and N content. The
value given is the mean of two determinations using approximately 4
mg each.
[0063] The optical rotation is measured using a Perkin Elmer model
241 polarimeter, the concentration is 1% in methanol unless
otherwise stated.
[0064] LC-MS is performed using a Waters Symmetry C-18 column, 0.46
cm ID.times.3 cm L, 3.5 .mu.m, at 60.degree. C. The eluent is a
gradient of (A) water with 0.05% trifluoroacetic acid and (B)
acetonitril with 5% water and 0.035% trifluoroacetic acid, going
from 90% A and 10% B to 100% B in 2 minutes; flow 3 ml/min.
Detection is performed using a Shimadzu detector at 254 nm. The
mass spectrum is recorded by a Sciex API300 mass spectrometer.
SYNTHESIS
Synthesis of Key Starting Materials
[0065] Compound V is synthesised from IV by reduction with sodium
borohydride (NaBH.sub.4) adapting a method described in Bogeso J.
Med. Chem. 1983, 26, 935, using ethanol as solvent, and performing
the reaction at approximately 0.degree. C. Both compounds are
described in Bogeso et al. J. Med. Chem. 1995, 38, 4380-4392.
Compound IV is synthesised from II using the general procedures
described in Sommer et al., J. Org. Chem. 1990, 55, 4822, which
also describes II and the synthesis thereof.
Example 0a
Synthesis of (S)-6-chloro-3-phenylindan-1-one (IVa) and
(R)-6-chloro-3-phenylindan-1-one (IVb) by use of chiral
chromatography
[0066] Racemic 6-chloro-3-phenylindan-1-one (IV) is resolved by
preparative chromatography, using a CHIRALPAK.RTM. AS-V column. A
mixture of n-heptane, ethanol and NAT-diethylamine is used as
mobile phase, detection is performed using a UV detector at 220 nm.
The racemic ketone (IV) is injected as a solution in the eluent;
suitable volumes of the solution is injected with suitable
intervals. All the fractions, which contain compound (IVa) with
more than 98% enantiomeric excess, are combined and evaporated to
dryness using a rotary evaporator. All fractions, which contain
compound (IVb) or mixtures of compounds (IVa) and (IVb) are
combined and evaporated to dryness using a rotary evaporator.
Example 0b
Synthesis of enantiomeric pure (R)-6-chloro-3-phenylindan-1-one
(IVb) by oxidation of (1R,3R)-6-chloro-3-phenylindan-1-ol (Vb)
[0067] (1R,3R)-6-chloro-3-phenylindan-1-ol (Vb) isolated as in
example 1a (20 g) is dissolved in dichloromethane (400 ml) and
pyridinium chlorochromate (PCC) (26.5 g) is added. The mixture is
stirred for 11/2 hour at room temperature. The mixture is filtered,
and the oily residue in the reaction vessel is washed with
dichloromethane. The combined organic fractions are evaporated to
dryness on a rotary evaporator, giving a black oil (25 g). Ethyl
acetate (200 ml) and sodium hydroxide (2M in water, 200 ml) are
added. The phases are separated, and the water phase is extracted
twice with ethyl acetate (200 ml). The combined organic phases are
washed three times with sodium hydroxide (2M in water, 100 ml),
twice with water (100 ml), and once with brine (100 ml), and
finally dried with sodium sulphate. Evaporation to dryness followed
by drying in a vacuum oven at 40.degree. C. gives 15 grams of
crystals. [.alpha.].sub.D.sup.20-61.degree. (c=1.0, methanol). 90%
ee according to the chiral analysis.
Example 0c Racemisation of (R)-6-chloro-3-phenylindan-1-one
(IVb)
[0068] Diisopropyl amine (5.1 ml) is dissolved in dry
tetrahydrofuran (THF) (50 ml) and the solution is stirred under
nitrogen with cooling in an acetone/dry ice bath. Butyl lithium
(1.6 M in hexane, 22.6 ml) is added slowly, where after the cooling
bath is replaced with an ice/water bath. After stirring for 11/2
hour, (R)-6-chloro-3-phenylindan-1-one (IVb) synthesised in example
0b (7.05 g, 90% ee) dissolved in dry THF (60 ml) is added over 30
minutes, and stirring on the cooling bath is continued for 17
minutes. Then potassium tert-butoxide (1.0 M in THF, 28.8 ml) is
added over 17 minutes, and then stirring is continued for another
two hours on the ice/water bath. The reaction mixture is quenched
with hydrochloric acid (4 M, 50 ml), and then THF is removed from
the mixture on the rotary evaporator. Water (200 ml) and diethyl
ether (350 ml) are added, and the phases are separated. The water
phase is extracted twice with diethyl ether (200 ml, then 100 ml).
The combined organic phases are washed twice with water (100 ml),
once with brine (100 ml), and dried with sodium sulphate.
Evaporation to dryness on a rotary evaporator, followed by drying
in a vacuum oven at 40.degree. C., gives 6.70 g of a red solid.
[.alpha.].sub.D.sup.20-2.34.degree. (c=1.0, methanol). The product
has an enantiomeric excess of 2% according to the chiral analysis,
and contains 6% of the by product (see body text) according to
HPLC. The raw product (4.99 g) is recrystallised from absolute
ethanol (40 ml), giving 3.71 g of a red solid.
[.alpha.].sub.D.sup.20-0.84.degree. (c=1.0, methanol). Contains
2.6% of the by product (see body text) according to HPLC.
Example 1a
Synthesis of (1S,3S)-6-chloro-3-phenylindan-1-ol (Va) and
(1R,3R)-6-chloro-3-phenyl-indan-1-ol (Vb) by use of chiral
chromatography
[0069] Racemic cis-6-chloro-3-phenylindan-1-ol (V) (492 grams) is
resolved by preparative chromatography, using a CHIRALPAK.RTM. AD
column, 10 cm ID.times.50 cm L, 10 .mu.m at 40.degree. C. Methanol
is used as mobile phase at a flow rate of 190 ml/min, detection is
performed using a UV detector at 287 nm. The racemic alcohol (V) is
injected as a 50,000 ppm solution in methanol; 90 ml is injected
with intervals of 28 min. All the fractions, which contain compound
(Va) with more than 98% enantiomeric excess, are combined and
evaporated to dryness using a rotary evaporator, followed by drying
"in vacuo" at 40.degree. C. Yield 220 grams as a solid. Elemental
analysis and NMR conform to the structure, the enantiomeric excess
is higher than 98% according to chiral HPLC,
[.alpha.].sub.D.sup.20+44.5.degree. (c=1.0, methanol). Likewise,
the fractions, which contain compound (Vb) are combined and
evaporated to dryness, giving 214 g of (Vb).
Example 1b
Synthesis of (1S,3S)-6-chloro-3-phenylindan-1-ol (Va) by reduction
of enantiomeric pure (IVa)
[0070] (S)-6-chloro-3-phenylindan-1-one (IVa) can by reduced with
sodium borohydride adapting a method described in Bogeso J. Med.
Chem. 1983, 26, 935, using ethanol as solvent and performing the
reaction at approximately 0.degree. C., giving compound (Va).
Example 2
Synthesis of (1S,3S)-3,5-dichloro-1-phenylindan (VI, LG=Cl)
[0071] Cis-(1S,3S)-6-chloro-3-phenylindan-1-ol (Va) (204 grams)
obtained as described in Example 1a is dissolved in THF (1500 ml)
and cooled to -5.degree. C. Thionyl chloride (119 grams) is added
drop wise as a solution in THF (500 ml) over a period of 1 h. The
mixture is stirred at room temperature over night. Ice (100 g) is
added to the reaction mixture. When the ice has melted the water
phase (A) and the organic phase (B) are separated, and the organic
phase B is washed twice with saturated sodium bicarbonate (200 ml).
The sodium bicarbonate phases are combined with water phase A,
adjusted to pH 9 with sodium hydroxide (28%), and used to wash the
organic phase B once again. The resulting water phase (C) and the
organic phase B are separated, and the water phase C is extracted
with ethyl acetate. The ethyl acetate phase is combined with the
organic phase B, dried with magnesium sulphate, and evaporated to
dryness using a rotary evaporator, giving the title compound as an
oil. Yield 240 grams, which is used directly in the example 5.
Cis/trans ratio 77:23 according to NMR.
Example 3
Synthesis of 3,3-dimethylpiperazin-2-one
[0072] Potassium carbonate (390 grams) and ethylene diamine (1001
grams) are stirred with toluene (1.50 l). A solution of ethyl
2-bromoisobutyrate (500 grams) in toluene (750 ml) is added. The
suspension is heated to reflux over night, and filtered. The filter
cake is washed with toluene (500 ml). The combined filtrates
(volume 4.0 l) are heated on a water bath and distilled at 0.3 atm.
using a Claisen apparatus; first 1200 ml distillate is collected at
35.degree. C. (the temperature in the mixture is 75.degree. C.).
More toluene is added (600 ml), and another 1200 ml distillate is
collected at 76.degree. C. (the temperature in the mixture is
80.degree. C.). Toluene (750 ml) is added again, and 1100 ml of
distillate is collected at 66.degree. C. (temperature in the
mixture 71.degree. C.). The mixture is stirred on an ice bath and
seeded, whereby the product precipitates. The product is isolated
by filtration, washed with toluene, and dried over night in a
vacuum oven at 50.degree. C. Yield 171 g (52%) of
3,3-dimethylpiperazin-2-one. NMR consistent with structure.
Example 4
Synthesis of 2,2-dimethylpiperazine
[0073] A mixture of 3,3-dimethylpiperazin-2-one (8.28 kg, 64.6 mol)
and tetrahydrofuran (THF) (60 kg) is heated to 50-60.degree. C.,
giving a slightly unclear solution. THF (50 kg) is stirred under
nitrogen, and LiAlH.sub.4 (250 g, in a soluble plastic bag) is
added, which gives a slow evolution of gas. After gas evolution has
ceased, more LiAlH.sub.4 is added (a total of 3.0 kg, 79.1 mol, is
used), and the temperature rises from 22.degree. C. to 50.degree.
C. because of an exoterm. The solution of
3,3-dimethylpiperazin-2-one is added slowly over 2 hours at
41-59.degree. C. The suspension is stirred for another hour at
59.degree. C. (jacket temperature 60.degree. C.). The mixture is
cooled, and water (3 l) is added over two hours, keeping the
temperature below 25.degree. C. (it is necessary to cool with a
jacket temperature of 0.degree. C.). Then sodium hydroxide (15%,
3.50 kg) is added over 20 minutes at 23.degree. C., cooling
necessary. More water (9 l) is added over half an hour (cooling
necessary), and the mixture is stirred over night under nitrogen.
Filter agent Celit (4 kg) is added, and the mixture is filtered.
The filter cake is washed with THF (40 kg). The combined filtrates
are concentrated in the reactor until the temperature in the
reactor is 70.degree. C. (distillation temperature 66.degree. C.)
at 800 mbar. The remanence (12.8 kg) is further concentrated on a
rotavapor to approximately 10 l. Finally, the mixture is
fractionally distilled at atmospheric pressure, and the product is
collected at 163-4.degree. C. Yield 5.3 kg (72%). NMR complies with
the structure.
Example 5
Synthesis of
trans-1-((1R,3S)-6-chloro-3-phenylindan-1-yl)-3,3-dimethylpiperazinium
(Compound I) hydrogen maleate salt
[0074] Cis-(1S,3S)-3,5-dichloro-1-phenylindan (VI, LG=Cl) (240 g)
is dissolved in butan-2-one (1800 ml). Potassium carbonate (272 g)
and 2,2-dimethyl piperazine (prepared in Example 4) (113 g) are
added and the mixture is heated at reflux temperature for 40 h. To
the reaction mixture is added diethyl ether (2 l) and hydrochloric
acid (1M, 6 l). The phases are separated, and pH in the water phase
is lowered from 8 to 1 with concentrated hydrochloric acid. The
water phase is used to wash the organic phase once again in order
to ensure, that all product is in the water phase. Sodium hydroxide
(28%) is added to the water phase until pH is 10, and the water
phase is extracted twice with diethyl ether (2 l). The diethyl
ether extracts are combined, dried with sodium sulphate, and
evaporated to dryness using a rotary evaporator. Yield 251 grams of
the title compound as an oil. Cis/trans ratio, 18:82 according to
NMR. The crude oil (ca. 20 grams) is further purified by flash
chromatography on silicagel (eluent: ethyl
acetate/ethanol/triethylamine 90:5:5) followed by evaporation to
dryness on a rotary evaporator. Yield 12 grams of the title
compound as an oil (cis/trans ratio, 10:90 according to NMR). The
oil is dissolved in ethanol (100 ml), and to this solution is added
a solution of maleic acid in ethanol to pH 3. The resulting mixture
is stirred at room temperature for 16 hours, and the formed
precipitate is collected by filtration. The volume of ethanol is
reduced and another batch of precipitate is collected. Yield 3.5
gram solid (no cis isomer is detected according to NMR) of the
title compound. Enantiomeric excess according to CE is >99%.
Melting point 175-178.degree. C. NMR complies with the
structure.
Example 6
Screening conditions for the resolution of
6-chloro-3-phenylindan-1-one (IV) by Super Critical Fluid
chromatography
[0075] A series of columns is screened for the ability of resolving
(IV) using a Gilson SF3 Supercritical Fluid Chromatography System.
Eluent: Different solvents containing 0.1% diethylamine are used as
modifier (30%), the flow is 4 ml/min, the pressure is 200 bar, and
the column is kept at room temperature. Detection is performed
using a Gilson UV/VIS-831 detector at 254 nm. The retention time of
the two enantiomers (RT.sub.1 and RT.sub.2) and the width in half
height of the two peaks (.OMEGA..sub.1 and .OMEGA..sub.2) are
calculated using Gilson Unipoint, version 3.2, software. The table
below gives the resolution (R.sub.S) calculated for the individual
columns with a series of modifiers; R.sub.S is calculated from the
formula
R.sub.S=2(RT.sub.2-RT.sub.1)/(.OMEGA..sub.1+.OMEGA..sub.2)
TABLE-US-00001 R.sub.S Column Meth- Eth- Isopro- Name
Dimensions.sup.a anol anol panol Acetonitril Chiralpak .RTM. AD-H
4.6, 250, 5 17.1 10.0 2.0 19.1 Chiralpak .RTM. AS-H 4.6, 250, 5 3.5
4.0 4.9 3.6 Chiralcel .RTM. OD-H 4.6, 250, 5 4.0 3.2 2.8 --
Chiralcel .RTM. OJ-H 4.6, 250, 5 0.7 0.0 0.0 -- Chiralpak .RTM. IA
4.6, 250, 5 5.4 2.8 0.6 2.6 (R,R)-Whelk-O 1 .RTM. 4.6, 250, 5 1.0
1.1 1.7 -- .sup.aInternal Diameter (mm), Column length (mm),
particle size (.mu.m)
Example 7
Resolution of 6-chloro-3-phenylindan-1-one (IV) by Super Critical
Fluid chromatography
[0076] The resolution is performed using the Berger Multigram II
Prep-SFC system with a CHIRALPAK.RTM. AD-H column, 20 mm
ID.times.250 mm L, 5 .mu.m. Eluent: Ethanol is used as modifier
(20%), the flow is 50 ml/min, the pressure is 100 bar, and the
column is kept at 35.degree. C. Detection is performed using a UV
detector at 230 nm. A Berger separator is used for fraction
collection and decompression. The equipment is controlled by SFC
Pronto software. The two enantiomers have the retention time 3.9
min. (IVa) and 4.8 min. (IVb). The racemic ketone (IV) is injected
as a solution in acetonitril (55 g of (IV) in 800 ml acetonitril);
500 .mu.l of this solution is injected with intervals of 132
seconds. All the fractions containing compound (IVa) are combined
and decompressed giving a solution of (IVa) in ethanol, and all the
fractions containing compound (IVb) are combined and decompressed
as well.
[0077] Compound (IVa) is isolated by evaporating the solution on a
rotary evaporator, and drying the residue in a vacuum oven at
40.degree. C. Yield 25.6 g (47%) of solid. Melting point
110.8.degree. C., NMR conforms to structure,
[.alpha.].sub.D.sup.20+72.65.degree. (c=1.0, methanol). CHN
calculated for C.sub.15H.sub.11OCl: C, 74.23; H, 4.57. found: C,
74.09; H, 4.70. >99% ee according to the chiral analysis.
[0078] Compound (IVb) is isolated in the same way, giving 23.9 g
(43%) of solid. Melting point 110.6.degree. C., NMR conforms to
structure, [.alpha.].sub.D.sup.20-70.33 (c=1.0, methanol). CHN
calculated for C.sub.15H.sub.11OCl: C, 74.23; H, 4.57. found: C,
73.79; H, 4.70. >99% ee according to the chiral analysis.
Example 8
Synthesis of (1S,3S)-6-chloro-3-phenylindan-1-ol (Va) by reduction
of enantiomeric pure (IVa)
[0079] (S)-6-chloro-3-phenylindan-1-one (IVa) (isolated as in
example 7) (23 g) is added in small portions to a suspension of
sodium borohydride (1.6 g) in ethanol (160 ml) at 3-5.degree. C.
After the addition has been finalised, the mixture is allowed to
reach room temperature. The reaction mixture is stirred for 2.75
hours, where after it is evaporated to dryness. The residue is
dissolved in a mixture of water (150 ml) and ethyl acetate (200
ml), the phases are separated, and the water phase is extracted
with ethyl acetate (100 ml). The organic phases are combined,
washed with water (100 ml), dried with magnesium sulphate, filtered
and evaporated to dryness. The residue is recrystallised from
heptanes (250 ml), giving 20.9 g (90%) of the title product as a
solid. Melting point 108.9.degree. C., NMR conforms to structure,
[.alpha.].sub.D.sup.20+48.30.degree. (c=1.0, methanol). CHN
calculated for C.sub.15H.sub.13OCl: C, 73.62; H, 5.35. found: C,
73.55; H, 5.29. >99% ee according to the chiral analysis.
Example 9
Synthesis of (1S,3S)-3,5-dichloro-1-phenylindan (VI, LG=Cl)
[0080] A solution of (1S,3S)-6-chloro-3-phenylindan-1-ol (Va) (17
g) (synthesized as in example 8) in tetrahydrofuran (130 ml) is
cooled with an ice bath. Thionyl chloride (9.9 g) in
tetrahydrofuran (50 ml) is added drop wise at 4-5.degree. C., and
then the mixture is stirred over night at ambient temperature. A
mixture of water and ice (approximately 25 ml) is added, and
stirring is continued until all the ice has melted. The phases are
separated, and the organic phase is washed twice with sodium
bicarbonate (5% in water, 25 ml). The water phases are then
combined, extracted with the organic phase, and then extracted with
ethyl acetate (50 ml). The organic phases are then combined, dried
with magnesium sulfate, filtered, and evaporated to dryness using a
rotary evaporator. Yield 18.7 g (102%) of the title compound as an
oil, which partly solidifies. The content of
(1S,3R)-3,5-dichloro-1-phenylindan is 18% according to NMR.
Example 10
Synthesis of
trans-1-((1R,3S)-6-chloro-3-phenylindan-1-yl)-3,3-dimethylpiperazine
(Compound I)
[0081] A mixture of (1S,3S)-3,5-dichloro-1-phenylindan (VI, LG=Cl)
(18 g) (synthesised as in example 9), potassium carbonate (20.8 g),
2,2-dimethylpiperazine, and methyl ethyl ketone (135 ml) is heated
to reflux over night. After cooling to room temperature, diethyl
ether (150 ml) and hydrochloric acid (1 M, 450 ml) are added, and
the mixture is stirred for a few minutes. The phases are separated,
and the pH in the water phase is adjusted from 1 to 12 using sodium
hydroxide (28%). The water phase is extracted with diethyl ether
(two times 170 ml). All the organic phases are combined, dried with
magnesium sulphate, filtered, and evaporated using a rotary
evaporator. Yield 20.7 g (89%) of the title compound as an oil. The
content of the cis isomer is 19% according to NMR.
Example 11
Synthesis of
trans-4-((1R,3S)-6-chloro-3-phenylindan-1-yl)-1,2,2-trimethylpiperazinium
(IX) hydrogen fumarate
[0082]
Trans-1-((1R,3S)-6-chloro-3-phenylindan-1-yl)-3,3-dimethylpiperazin-
e (I, synthesised as in example 10) is stirred with formic acid
(15.2 ml) and formaldehyde (37% in water, 12.5 ml), and heated on
an oil batch (temperature 110.degree. C.) for 11/2 hour. Water is
added to the reaction mixture after cooling to room temperature,
and pH is adjusted to approximately 14 with sodium hydroxide (28%).
The product is extracted with diethyl ether and then ethyl acetate,
adding sodium hydroxide (28%) in between the extractions, if the pH
becomes lower than 12. The organic phases are combined, dried with
sodium sulphate, filtered, and evaporated to dryness, using a
rotary evaporator. Yield 10.9 g (100%) of (IX) as an oil,
containing 20% of the cis form according to NMR.
[0083] The oil (10 g) is heated with 1-propanol (150 ml), giving a
solution. Fumaric acid (3.3 g) is added, and heating is continued
until all is dissolved. The mixture is cooled to room temperature
and seeded, whereby the product precipitates. The solid is isolated
by filtration, washed with a small amount of 1-propanol, and dried
in a vacuum oven at 40.degree. C. Yield 6.85 g (52%). Melting point
193.3.degree. C., NMR conforms to structure,
[.alpha.].sub.D.sup.20-15.2.degree. (c=1.0, methanol). Contains 4%
of the cis form according to CE, the other two diastereoisomers are
not detected (i.e. the content is below 1%). CHN calculated for
C.sub.26H.sub.31N.sub.2O.sub.4Cl: C, 66.30; H, 6.63, N, 5.95.
found: C, 65.96; H, 6.61; N, 5.57. >98% ee according to CE.
Example 12
Synthesis of enantiomeric pure (R)-6-chloro-3-phenylindan-1-one
(IVb) by oxidation of (1R,3R)-6-chloro-3-phenylindan-1-ol (Vb)
[0084] Pyridinium chlorochromat (66.1 g) is added to a solution of
(1R,3R)-6-chloro-3-phenyl-indan-1-ol (Vb) (isolated as in example
1a) (50.0 g) in dichloromethane (840 ml), and the mixture is
stirred at ambient temperature for two hours. The mixture is
filtered, and the residue in the vessel is washed twice with
dichloromethane (200 ml), which is used to wash the filter cake as
well. The combined filtrates are evaporated to dryness, using a
rotary evaporator. The residue is stirred with sodium hydroxide (2
M, 1 l) and ethyl acetate (750 ml) for 1/2 an hour. The phases are
separated, and the water phase is extracted with ethyl acetate (500
ml). The combined organic phases are washed twice with sodium
hydroxide (2 M, 250 ml), and 25% sodium chloride (250 ml). Then the
organic phase is stirred with magnesium sulphate (60 g), charcoal
(1.4 g), and silica gel 60 (0.06-0.2 mm, 5 g), filtered, and
evaporated to dryness using a rotary evaporator. The residue (31.5
g) is recrystallised from 2-propanol (125 ml); the product is
isolated by filtration and washed with 2-propanol (40 ml). Drying
in a vacuum oven at 50.degree. C. gives 26.0 g (53%) of the product
as a solid. Melting point 110.8.degree. C., NMR conforms to
structure, [.alpha.].sub.D.sup.20-75.6.degree. (c=1.0, methanol).
CHN calculated for C.sub.15H.sub.11OCl: C, 74.23; H, 4.57; N, 0.00.
found: C, 73.89; H, 4.71; N, 0.05. 99.2% ee according to the chiral
analysis.
[0085] The reaction was repeated twice giving 48 g of the product
with 99.6% ee, and 48 g of the product with 98.9% ee,
respectively.
Example 13
Screening of bases for the racemisation of
(R)-6-chloro-3-phenyl-indan-1-one (IVb)
[0086] The bases used are from Aldrich: Butyl lithium (BuLi)
catalogue no. 18, 617-1, tert-butyl lithium (tBuLi) catalogue no.
18, 619-8, potassium tert-butoxide (KOtBu) catalogue no. 32, 865-0,
Lithium tert-butoxide (LiOtBu) catalogue no. 398195, sodium
tert-butoxide (NaOtBu) catalogue no. 35, 927-0, lithium
bis(trimethylsilyl)amide (LiHMDS) catalogue no. 225770, sodium
bis(trimethylsilyl)amide (NaHMDS) catalogue no. 24, 558-5, and
potassium bis(trimethylsilyl)amide (KHMDS) catalogue no. 324671.
Lithium diisopropylamide is made from diisopropylamine
(Sigma-Aldrich catalogue no. 386464) and BuLi just before use in
every experiment.
[0087] The following procedure is typical for the experiments and
illustrates the use of LDA and the use of two different bases:
A mixture of diisopropylamine (437 .mu.l) and tetrahydrofuran (THF)
(4 ml) is stirred under nitrogen and cooled with a batch of dry ice
and acetone. Butyl lithium (BuLi) (1.6 M in hexanes, 1.60 ml) is
added over 5 minutes. Stirring is continued for 10 minutes, and
then the cooling batch is replaced with an ice-water batch. After
stirring for another 10 minutes, a solution of
(R)-6-chloro-3-phenylindan-1-one (IVb) (synthesised as in example
12) (0.50 g) in THF (4 ml) is added drop wise over 5 minutes to the
solution of LDA ("the former base", base 1), and stirring at the
water-ice batch is continued for 1/2 an hour. Then BuLi (1.6 M in
hexanes) (1.61 ml) ("the latter base", base 2) is added drop wise
over 5 minutes, where after stirring at the ice-water batch is
continued for 21/2 hours, and then hydrochloric acid (4 M, 4 ml) is
added. After stirring for 10 minutes, the phases are separated, and
the water phase is extracted with ethyl acetate (two times 10 ml).
The combined organic phases are washed with sodium chloride (25%,
10 ml), dried with magnesium sulphate, filtered, and evaporated to
dryness using a rotary evaporator. Yield 0.47 g (94%) of an oil,
the chemical purity is 83% according to LC-MS, and the enantiomeric
excess is 1% according to the chiral analysis.
[0088] The table below summarises the results obtained:
TABLE-US-00002 Purity of Equivalents Equivalents Time.sup.1) raw
Entry of base 1 Base 1 of base 2 Base 2 hr product % ee.sup.2) % 1
2.25 LDA.sup.3) N/A N/A 2.5 91 2 2 2.25 KOtBu N/A N/A 2.5 38 -10 3
2.25 BuLi N/A N/A 2.5 39 5 4 2.25 tBuLi N/A N/A 2.5 40 -13 5 1.25
LDA.sup.4) 1.25 BuLi 2.5 83 1 6 1.25 LDA.sup.4) 1 KOtBu 2.5 88 0 7
1.25 LDA.sup.4) 1.25 tBuLi 2.5 88 -4 8 1.25 LiHMDS 1 KOtBu 2.5 86 1
9 1.25 LiOtBu 1 KOtBu 2.5 93 0 10 1.25 LDA.sup.5) 1 BuLi 0.5 82 2
11 1.25 LDA.sup.5) 1 BuLi 1 93 2 12 1.25 LDA.sup.5) 1 BuLi 2.5 90
-3 13.sup.6) 1.25 LDA.sup.5) 1 BuLi 0.5 85 2 14.sup.6) 1.25
LDA.sup.5) 1 BuLi 1 85 2 15.sup.6) 1.25 LDA.sup.5) 1 BuLi 2.5 86 -1
.sup.1)Indicating the time for stirring at 0.degree. C. after all
has been mixed. .sup.2)Enantiomeric excess; a negative sign
indicates, that IVa is in excess, impurities in the sample may
interfere with the analysis. .sup.3)LDA is made using 2.50
equivalents of diisopropylamine and 2.25 equivalents of BuLi.
.sup.4)LDA is made using 1.50 equivalents of diisopropylamine and
1.25 equivalents of BuLi. .sup.5)LDA is made using 1.25 equivalents
of diisopropylamine and 1.50 equivalents of BuLi. .sup.6)In these
experiments, all BuLi - also the amount indicated as base 2 - is
added from the beginning of the experiments, before the addition of
compound IVb.
Example 14
Scale up of racemisation of (R)-6-chloro-3-phenyl-indan-1-one
(IVb)
[0089] The bases used are the same as in example 13.
[0090] A representative procedure is as follows:
Diisopropylamine (6.25 g) is dissolved in tetrahydrofuran (THF)
(160 ml), and the mixture is cooled with an dry ice/acetone batch
while stirring under nitrogen. Butyl lithium (1.6 M in hexanes, 33
ml) is added slowly keeping the temperature below -60.degree. C.
Stirring is continued for 5 minutes at the dry ice/acetone batch,
which is then replaced by an ice/water batch. The mixture is
stirred for 10 minutes at -10 to 0.degree. C., where after a
solution of (R)-6-chloro-3-phenylindan-1-one (IVb) (synthesised as
in example 12) (10.0 g) in THF (80 ml) is added slowly keeping the
temperature below 5.degree. C. After stirring for approximately 1/2
an hour, butyl lithium (1.6 M in hexanes, 33 ml) is added slowly,
keeping the temperature below 5.degree. C. After stirring at
0-5.degree. C. for 21/2 hours, hydrochloric acid (4 M, 100 ml) is
added slowly. The phases are separated, and the water phase is
extracted two times with ethyl acetate (100 ml). The combined
organic phases are washed with 25% sodium chloride (100 ml), and
stirred for 10 minutes with magnesium sulphate (26 g), charcoal (1
g), and silica gel (2.6 g). After filtration, the organic phase is
evaporated to dryness using a rotary evaporator. The residue is
recrystallised from 2-propanol (40 ml). The product is isolated by
filtration, washed with ice cold 2-propanol (20 ml), and dried in
the vacuum oven at 50.degree. C. over night. Yield 5.85 g (60%).
Melting point 95.2.degree. C., NMR conforms to structure,
[.alpha.].sub.D.sup.20-1.1.degree. (c=1.0, methanol). CHN
calculated for C.sub.15H.sub.11OCl: C, 74.23; H, 4.57. found: C,
74.29; H, 4.62. -1.0% ee according to the chiral analysis. Purity
97% according to LC-MS.
[0091] The results are summarised in the table below:
TABLE-US-00003 Equivalents Equivalents Time.sup.1) Entry of base 1
Base 1 of base 2 Base 2 hr Yield % Purity % ee.sup.2) % 1 2.25
LDA.sup.3) N/A N/A 2.5 53 97 -3 2 1.25 LDA.sup.4) 1.25 BuLi 2.5 60
97 -1 3 1.25 LDA.sup.4) 1 KOtBu 2.5 76 87 0 4 1.25 LiOtBu 1 KOtBu
2.5 70 79 -2 5 1.25 LDA.sup.5) 1 BuLi 2.5 70 97 0 6.sup.6) 1.25
LDA.sup.6) 1.25 BuLi 1/2 59 96 0 .sup.1)Indicating the time for
stirring at 0.degree. C. after all has been mixed.
.sup.2)Enantiomeric excess; a negative sign indicates, that IVa is
in excess. .sup.3)LDA is made using 2.50 equivalents of
diisopropylamine and 2.25 equivalents of BuLi. .sup.4)LDA is made
using 1.50 equivalents of diisopropylamine and 1.25 equivalents of
BuLi. .sup.5)LDA is made using 1.25 equivalents of diisopropylamine
and 1.50 equivalents of BuLi. .sup.6)In this experiments, all BuLi
- also the amount indicated as base 2 - is added from the beginning
of the experiments, before the addition of compound IVb; i.e. 1.25
equivalents of diisopropylamine and a total of 2.50 equivalents of
BuLi is used.
* * * * *