U.S. patent application number 10/760515 was filed with the patent office on 2004-08-05 for method for the isolation of sulfuric acid mono-[3({1-[2-(4-fluorophenyly)-- ethyl]-piperidin-4-yl}-2-methoxy-phenyl}ester.
This patent application is currently assigned to Aventis Pharmaceuticals Inc.. Invention is credited to Bernotas, Ronald Charles, Brown, Paul Wayne, Emmons, Gary Thomas, King, Chi-Hsin Richard.
Application Number | 20040152900 10/760515 |
Document ID | / |
Family ID | 26893579 |
Filed Date | 2004-08-05 |
United States Patent
Application |
20040152900 |
Kind Code |
A1 |
Bernotas, Ronald Charles ;
et al. |
August 5, 2004 |
Method for the isolation of sulfuric acid
mono-[3({1-[2-(4-fluorophenyly)--
ethyl]-piperidin-4-yl}-2-methoxy-phenyl}ester
Abstract
The present invention is directed to the method of isolation of
sulfuric acid
mono-[3-({1-[2-(4-fluoro-phenyl)-ethyl]-piperidin-4-yl}-hydroxy-meth-
yl)-2-methoxy-phenyl]ester, a metabolite of the 5HT.sub.2A
antagonist
(+)-.alpha.-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidin-
emethanol.
Inventors: |
Bernotas, Ronald Charles;
(Bridgewater, NJ) ; Brown, Paul Wayne; (Leawood,
KS) ; Emmons, Gary Thomas; (Washington, NJ) ;
King, Chi-Hsin Richard; (Slingerlands, NY) |
Correspondence
Address: |
ROSS J. OEHLER
AVENTIS PHARMACEUTICALS INC.
ROUTE 202-206
MAIL CODE: D303A
BRIDGEWATER
NJ
08807
US
|
Assignee: |
Aventis Pharmaceuticals
Inc.
Bridgewater
NJ
|
Family ID: |
26893579 |
Appl. No.: |
10/760515 |
Filed: |
January 20, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10760515 |
Jan 20, 2004 |
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10200821 |
Jul 22, 2002 |
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6716986 |
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10200821 |
Jul 22, 2002 |
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09615246 |
Jul 13, 2000 |
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6465490 |
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60198215 |
Jul 16, 1999 |
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Current U.S.
Class: |
546/241 ;
436/96 |
Current CPC
Class: |
A61K 31/445 20130101;
Y10T 436/145555 20150115; C07D 211/22 20130101 |
Class at
Publication: |
546/241 ;
436/096 |
International
Class: |
G01N 033/00; C07D
211/22 |
Claims
What is claimed is:
1. A method of isolating a compound of formula I or its enantiomers
from an appropriate sample comprising the steps of: 20a) collecting
the sample from a patient wherein the patient has been administered
a therapeutically sufficient amount of
(+)-.alpha.-(2,3-dimethoxyphenyl)-1--
[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol; b) optionally
preparing the sample for isolation of the compound of Formula I or
its enantiomers; and c) isolating the compound of Formula I or at
least one enantiomer from the sample.
2. A method according to claim 1 wherein the sample is plasma.
3. A method according to claim 1 wherein the sample is urine.
4. A method according to claim 1 wherein isolating is by
chromatography.
Description
[0001] This application is a division of U.S. application Ser. No.
10/200,821, filed Jul. 22, 2002, now allowed, which is a division
of Ser. No. 09/615,246, filed Jul. 13, 2000, now U.S. Pat. No.
6,465,490 B1, issued, Oct. 15, 2002, which claims the benefit of
U.S. Provisional Application No. 60/198,215, field Jul. 16,
1999.
FIELD OF THE INVENTION
[0002] The present invention relates to a method of isolation of
sulfuric acid
mono-[3-({1-[2-(4-fluoro-phenyl)-ethyl]-piperidin-4-yl}-hydroxy-meth-
yl)-2-methoxy-phenyl]ester. It is a pharmaceutically active
compound useful as an antagonist of serotonin at the 5HT.sub.2A
receptor. It is useful in treating conditions and diseases such as
schizophrenia, anxiety, variant angina, anorexia nervosa, Raynaud's
phenomenon, intermittent claudication, coronary or peripheral
vasospasms, fibromyalgia, cardiac arrhythmias, thrombotic illness,
controlling the extrapyramidal symptoms associated with neuroleptic
therapy, depressive and bipolar disorders, obsessive-compulsive
disorders, insomnia and sleep apnea.
BACKGROUND OF THE INVENTION
[0003]
(+)-.alpha.-(2,3-Dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-pip-
eridinemethanol has the following structure: 1
[0004] It is a novel pharmaceutically active compound in the
treatment of conditions and diseases useful as an antagonist of
serotonin at the 5HT2A receptor, and as such, is useful in a
variety of treatments such as schizophrenia, anxiety, variant
angina, anorexia nervosa, Raynaud's phenomenon, intermittent
claudication, coronary or peripheral vasospasms, fibromyalgia,
cardiac arrhythmias, thrombotic illness, controlling the
extrapyramidal symptoms associated with neuroleptic therapy,
depression, bipolar disorders, obsessive-compulsive disorders,
insomnia and sleep apnea.
.alpha.-(2,3-Dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperi-
dinemethanol has been generically described in U.S. Pat. No.
5,169,096, issued Dec. 8, 1992, the disclosure of which is
incorporated herein by reference.
(+)-.alpha.-(2,3-Dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]4-
-piperidinemethanol was thereafter described in U.S. Pat. No.
5,134,149, issued Jul. 28, 1992, the disclosure of which is
incorporated herein by reference. U.S. Pat. No. 5,700,813, issued
Dec. 23, 1997, U.S. Pat. No. 5,700,812, issued Dec. 23, 1997, U.S.
Pat. No. 5,561,144, issued Oct. 1, 1996, U.S. Pat. No. 5,721,249
issued February 23, 1998 and U.S. Pat. No. 5,874,445 issued Feb.
23, 1999, the disclosure of each which is incorporated herein by
reference, describe the use of
(+)-.alpha.-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidin-
emethanol as 5HT.sub.2A receptor antagonists in the treatment of a
number of disease states as described above. Other U.S. patents,
which describe the use of the generic species in the treatment of a
number of disease states, are U.S. Pat. Nos. 4,783,471; 4,877,798;
4,908,369; 4,912,117; 5,021,428; 5,106,855; 5,618,824 and U.S. Pat.
No. 5,478,846, which generically discloses intermediates. Each of
the preceding disclosures is incorporated herein by reference.
[0005] The compound of the present invention has been found to be
an active metabolite of
(+)-.alpha.-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophen-
yl)ethyl]-4-piperidinemethanol by virtue of its ability to act as
an antagonist at the 5HT.sub.2A receptor, and represents the major
metabolite of
(+)-.alpha.-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethy-
l]-4-piperidinemethanol found in plasma. The unsulfated version of
the present invention
(+)-.alpha.-(3-hydroxy-2-methoxyphenyl)-1-(2-(4-fluorop-
henyl)ethyl)4-piperidinemethanol is also a metabolite of
(+)-.alpha.-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]4-piperidine-
methanol as described in Heath, T. G. et al. J. Am. Soc. Mass
Spectrom. (1997), 8(4), 371-379, and Scott, D. et al. J. Pharm.
Biomed. Anal. (1998), 17(1), 17, incorporated herein by reference.
Even though the present invention is a mono sulfated conjugate of
(+)-.alpha.-(3-hydroxy--
2-methoxyphenyl)-1-(2-(4-fluorophenyl)ethyl)-4-piperidinemethanol,
unexpectedly, according to tests described hereafter, it has been
found to cross the blood-brain barrier and therefore may be useful
in the treatment of central nervous system conditions or diseases
which are treated by antagonizing the effects of serotonin at the
5HT.sub.2A receptor.
[0006] It is an object of the present invention to provide a
compound useful in treating a variety of diseases or conditions.
This compound should have a binding profile (affinity or lack of
affinity for specific receptors), which permits therapeutic
activity without undue side effects. For example, too much affinity
for the alpha1 receptor may result in orthostatic hypotension and
sedation. Too much affinity for the dopamine 2 (D.sub.2) receptor
can result in hyperprolactinemia, extrapyramidal side effects (EPS)
and tardive dyskinesia. Also, preferably the present invention
should cross the blood-brain barrier in order to be active against
diseases or conditions that affect the central nervous system. The
present invention solves these problems by having an effective
binding profile sufficient to treat certain diseases or conditions
without significant side effects and treats certain central nervous
systems diseases or conditions.
SUMMARY OF THE PRESENT INVENTION
[0007] The present invention is a method of isolating a compound of
formula I or its enantiomers from an appropriate sample comprising
the steps of: 2
[0008] a) collecting the sample from a patient wherein the patient
has been administered a therapeutically sufficient amount of
(+)-.alpha.-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidin-
emethanol;
[0009] b) optionally preparing the sample for isolation of the
compound of Formula I or its enantiomers; and
[0010] c) isolating the compound of Formula I or at least one
enantiomer from the sample.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0011] In general, various terms as used herein shall have the
following meanings unless otherwise defined:
[0012] (1) "Pharmaceutically acceptable salt" means either an acid
addition salt or a basic addition salt, which is compatible with
treatment of patients for the intended use.
[0013] "Pharmaceutically acceptable acid addition salt" is a
non-toxic organic acid addition salt of the base compounds
represented by Formula I, II or III or any of its intermediates.
Some examples of inorganic acids which form suitable salts include
hydrochloric, hydrobromic, sulfuric and phosphoric acid and acid
metal salts such as sodium monohydrogen orthophosphate, and
potassium hydrogen sulfate. Illustrative organic acids, which form
suitable salts, include the mono-, di, and tricarboxylic acids.
Examples of such acids are acetic, glycolic, lactic, pyruvic,
malonic, succinic, glutaric, fumaric, malic, tartaric, citric,
ascorbic, maleic, hydroxymaleic, benzoic, hydroxybenzoic,
phenylacetic, cinnamic, salicylic, 2-phenoxybenzoic, and sulfonic
acids such as p-toluenesulfonic acid, methane sulfonic acid and
2-hydroxyethane sulfonic acid. Such salts can exist in either a
hydrated or substantially anhydrous form. In general, the acid
addition hydrophilic organic salts in comparison to their free base
forms generally demonstrate higher melting points.
[0014] "Pharmaceutically acceptable base addition salts" means
non-toxic organic or inorganic basic addition salts of the
compounds of Formula (I) or any of its intermediates. Examples are
alkali metal or alkaline-earth metal hydroxides such as sodium,
potassium, calcium or organic amines such as methylamine,
trimethylamine and picoline.
[0015] (2) "Patient" means a warm blooded animal, such as, for
example, rat, mouse, dog, cat, guinea pig, and primates such as a
human.
[0016] (3) "Treat" or "treatment" means to prevent or alleviate
symptoms, eliminate the causation of the symptoms either on a
temporary basis, or to prevent or slow the appearance of symptoms
of the named disorder or condition.
[0017] (4) "Therapeutically sufficient amount" means a quantity of
the compound that is effective in treating the named disorder or
condition.
[0018] (5) "Amount sufficient to antagonize the effects of
serotonin at the 5 HT2A receptor" means a quantity of the compound
that is effective in antagonizing the effects of serotonin at the
5HT.sub.2A receptor.
[0019] (6) "Administering or administration" means a suitable route
for giving a therapeutically sufficient amount of drug to a
patient. Examples of suitable routes are oral, buccal, sublingual,
parenteral, intravenous and topical, including a topical patch
administration. Furthermore, this also means giving a prodrug to
the patient in order to produce the compound of interest at the
site of action in the body. For example, the prodrug
(+)-.alpha.-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-p-
iperidinemethanol is administered to the patient to provide at
least the compound sulfuric acid
mono-(+)-[3-({1-[2-(4-fluoro-phenyl)-ethyl]-piperi- din-4-yl
}-hydroxy-methyl)-2-methoxy-phenyl]ester and possibly the (-)
enantiomer thereof.
[0020] (7) "Schizophrenia" means a condition where a patient
suffers a mental disturbance that lasts at least 6 months and
includes 1 month of active-phase symptoms, such as two or more of
the following: delusions, hallucinations, disorganized speech,
grossly disorganized or catatonic behavior, and negative
symptoms.
[0021] (8) "Anxiety" means a condition where a patient suffers an
apprehension of danger and dread accompanied by restlessness,
tension, tachycardia and dyspnea unattached to a clearly
identifiable stimulus.
[0022] (9) "Variant angina" means a condition where the patient
suffers from coronary vasospasms, which produce the chest pains
associated with angina. These vasospasms typically occur while the
patient is at rest.
[0023] (10) "Anorexia nervosa" means a condition where a patient
refuses to maintain a minimally normal body weight and is intensely
afraid of gaining weight, and exhibits a significant disturbance in
the perception of the shape or size of his or her body.
[0024] (11) "Raynaud's phenomenon" means a condition where the
patient suffers from a spasm of the digital arteries, with
blanching and numbness of or pain of the fingers, often
precipitated by cold.
[0025] (12) "Intermittent claudication" means a condition where the
patient suffers from, due to ischemia of the muscles, attacks of
lameness and pain, brought on by walking, chiefly in the calf
muscles; however, the condition may occur in other muscle
groups.
[0026] (13) "Coronary or peripheral vasospasms" means a condition
where the patient suffers from contraction and hypertonia of the
muscular coats of the cardiac or peripheral blood vessels.
[0027] (14) "Fibromyalgia" means a condition where the patient
suffers chronically from numerous symptoms such as, for example,
widespread generalized musculoskeletal pains, aching, fatigue,
morning stiffness and a sleep disturbance which can be
characterized as an inadequacy of stage 4 sleep.
[0028] (15) "Cardiac arrhythmia" means a condition where the
patient suffers from any variation from the normal rhythm of the
heart beat.
[0029] (16) "Thrombotic illness" means a condition where the
patient suffers from a clotting within a blood vessel, which may
cause infarction of tissues supplied by the vessel.
[0030] (17) "Extrapyramidal symptoms" means a condition where the
patient suffers from side effects from the administration of
neuroleptic agents such as haloperidol and chloropromazine. These
extrapyramidal side effects (EPS) can encompass Parkinsonian-like
syndromes, akathasia and acute dystonic reactions.
[0031] (18) "Depression" means a condition where the patient
suffers from a temporary mental state or chronic mental disorder
characterized by feelings of sadness, loneliness, despair, low
self-esteem and self-reproach; accompanying signs include
psychomotor retardation or less frequently agitation, withdrawal
from social contact and vegetative states such as loss of appetite
and insomnia.
[0032] (19) "Bipolar disorder" means a condition where the patient
suffers from alternating periods of euphoria and depression.
[0033] (20) "Obsessive-compulsive disorders" or "OCD" means a
condition where the patient exhibits recurrent obsessions or
compulsions that are severe enough to be time consuming (i.e., take
more than an hour a day) or cause marked distress or significant
impairment. Obsessions are persistent ideas, thoughts, impulses, or
images that are experienced as intrusive and inappropriate and that
cause marked anxiety or distress. Compulsions are repetitive
behaviors (e.g., hand washing, ordering, checking) or mental acts
(e.g., praying, counting, repeating words silently) the goal of
which is to prevent or reduce anxiety or distress, not to provide
pleasure or gratification.
[0034] (21) "Insomnia" means a condition where the patient suffers
from an inability to sleep in the absence of external impediments,
during the period when sleep should normally occur.
[0035] (22) "Sleep apnea" means a condition where the patient
suffers from a stoppage of breathing for at least 10 seconds or
more, and usually greater than 20 times/hour, causing measurable
blood deoxygenation.
[0036] (23) "Pharmaceutically acceptable carrier" is a non-toxic
solvent, dispersant, excipient, adjuvant or other material, which
is mixed with the active ingredient in order to permit the
formation of a pharmaceutical composition, i.e., a dosage form
capable of administration to the patient. One example of such a
carrier is pharmaceutically acceptable oil typically used for
parenteral administration.
[0037] (24) "Enantiomers" are a pair of isomers that are mirror
images of each other and not superposable.
[0038] (25) "Racemate" means a composite of two enantiomeric
species. It is devoid of optical activity.
[0039] (26) "Stereoisomer" is a general term for all isomers of
individual molecules that differ only in the orientation of their
atoms in space. It includes mirror image isomers (enantiomers),
geometric (cis/trans) isomers and isomers of compounds with more
than one chiral center that are not mirror images of one another
(diastereomers).
[0040] (27) "C.sub.1-C.sub.4 alkyl" and C.sub.1-6 alkyl" means a
straight or branched chain hydrocarbon radical of one to four and
one to six carbon atoms. Included within the scope of these terms
are methyl, ethyl, n-propyl, isopropyl, n- butyl, isobutyl, pentyl,
neopentyl, hexyl and the like.
[0041] (28) "Aralkyl" means an aryl or diaryl moiety connected to
the remainder of the molecule via an alkylene bridge. This alkylene
bridge can be straight or branched-chained and is one, two, three,
four, five or six carbons in length. "Aryl means an aromatic
radical having six atoms in a single ring system such as phenyl or
a fused ring system such as 1-napthyl, 2-napthyl and the like. The
aryl or diaryl group may be optionally substituted as described
herein. The substitutions may be at the ortho, meta or para
positions as appropriate. Examples of preferred aralkyls are
benzyl, phenylethyl, propylphenyl and diphenylbutyl.
[0042] (29) "Optionally substituted" means that the referenced
moiety is substituted as defined herein by the same or different
substituents, i.e. independently selected, from the group; of
hydrogen, halogen (fluorine, chlorine, iodine or bromine),
C.sub.1-6 alkyl, C.sub.1-6 alkoxy, C(.dbd.O)H, C(.dbd.O)C.sub.1-6
alkyl, CF.sub.3 or hydroxy with one, two or three substituents as
is suitable to the structure.
[0043] (30) "Prodrug" means a compound given to a patient, which is
then metabolized in the patient to another active compound. In the
present invention the prodrug is
(+)-.alpha.-(2,3-dimethoxyphenyl)-1-[2-(4-fluoro-
phenyl)ethyl]-4-piperidinemethanol.
[0044] (31) "Sample" means a quantity of either plasma, urine or
other component of the body from which the compounds of the present
invention may be found and isolated therefrom.
[0045] (32) "Optically active isomers" are isomers that rotate the
plane of polarized light and are designated (+) or (-).
[0046] The compounds of the invention may be prepared by the
synthetic routes described below in the Schemes or other methods,
which may be apparent to those skilled in the art. The
enantiomerically pure compounds of the invention may be prepared as
outlined in Scheme A. The scheme illustrates the synthesis of the
(+) enantiomer; however, as would be evident to one with ordinary
skill in the art, by starting with the appropriate (-) enantiomer
the sequence shown in Scheme A would afford the corresponding (-)
enantiomer of the invention. 3
[0047] Step A1: The compound 1,
(+)-.alpha.-(3-hydroxy-2-methoxyphenyl)-1--
[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol, a known metabolite
of
(+)-.alpha.-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidin-
emethanol as described in Heath, T. G. et al. J. Am. Soc. Mass
Spectrom. (1997), 8(4), 371-379, and Scott, D. et al. J. Pharm.
Biomed. Anal. (1998), 17(1), 17-25, (also see Scheme C), is reacted
with a suitable acylating agent to provide the diprotected compound
2, wherein Pg is a protecting group such as C.sub.1-6
alkylsulfonyl, trifluoroacetyl, or C(.dbd.O) C.sub.1-6 alkyl other
protecting groups may be used as is known to one skilled in the
art. The groups may be the same or different groups, but typically
are the same. Suitable acylating agents are, for example,
anhydrides and acid chlorides or bromides, with anhydrides
preferred. The reaction is performed under standard acylating
conditions well known to those with ordinary skill in the art.
[0048] Step A2: The diprotected compound 2 is then selectively
hydrolyzed to the monoprotected phenol 3. The reaction may be
carried out in an aqueous protic solvent with an alkali
bicarbonate. Examples of aqueous protic solvents are ethanol,
methanol, propanol and isopropanol that have been diluted with
varying proportions of water. The preferred aqueous protic solvent
is aqueous methanol. Examples of alkali bicarbonates are sodium,
cesium or potassium bicarbonate, sodium bicarbonate being
preferred. The reaction temperature may vary from 0.degree. C. to
the boiling point of the solvent. The preferred temperature is
between 0.degree. C. and room temperature.
[0049] Step A3: The monoprotected phenol 3 is converted to the
intermediate mono sulfuric acid ester 4 by reacting said
monoprotected phenol with a suitable sulfating agent. Suitable
sulfating agents are those compounds capable of adding sulfate at
the desired position. Examples of suitable sulfating agents are
sulfur trioxide pyridine complex, sulfur trioxide triethylamine
complex, sulfur trioxide dimethylformamide complex, sulfuric
acid-dicyclohexylcarbodiimide, chlorosulfonic acid with acid or
base, pyridine sulfur trioxide complex being preferred. The
reaction is carried out in an appropriate organic solvent. Examples
of appropriate organic solvents are benzene, toluene, acetonitrile,
dimethylformamide, dichloromethane and chloroform. The preferred
solvent is acetonitrile. The reaction temperature may vary from
room temperature to the boiling point of the solvent, a temperature
of about 45.degree. C. is preferred.
[0050] Step A4: Preferably without isolation of the sulfuric acid
ester 4 is reacted in situ with an alkali metal carbonate such as
sodium, potassium, or cesium carbonate, potassium carbonate
preferred, in an aqueous protic solvent such as methanol-water to
afford the sulfuric acid ester alcohol 5. The reaction temperature
may vary from room temperature to boiling point of the solvent, the
boiling point of the solvent is preferred.
[0051] Scheme B illustrates the synthesis of the racemate of 15
also known as Formula I. 45
[0052] Step B1: Guiacol, the compound 6, available from the Aldrich
Chemical Company, is reacted with a reagent to provide a suitable
protecting group, preferably a suitable trialkylsilyl halide to
form the monomethoxysilylether derivative 7. Suitable trialkylsilyl
halides, are compounds that would react with a phenolic oxygen to
produce a compound wherein R.sub.1.dbd.Si(R.sub.4).sub.3 and
R.sub.4 is C.sub.1-6 alkyl for example, t-butyldimethylsilyl
chloride and triisopropylsilyl chloride, with triisopropylsilyl
chloride being preferred. The purpose of the silyl substituent
(R.sub.1), besides protecting the phenolic oxygen, is also to
inhibit abstraction of the aromatic hydrogen that is adjacent
(ortho) to the OR, substituent, when the compound is treated with a
strong base. Consequently, upon reaction of said compound with a
strong base, the aromatic hydrogen ortho to the methoxy substituent
is abstracted regioselectively. Such a strategy has been previously
invoked by B. Trost, et al., Tetrahedron Lett., 1985, 26, 123-126
and J. J. Landi, et al. Synthetic Commun., 1991, 21, 167-171
incorporated herein by reference. The reaction is typically
effected by reaction of a trialkylsilyl halide, in the presence of
a suitable nucleophilic catalyst such as imidazole or
4-dimethylaminopyridine, imidazole being preferred, in a suitable
polar aprotic solvent. Examples of polar aprotic solvents are
dimethylformamide, 1-methyl-2-pyrrolidinone, dimethylsulfoxide,
hexamethylphosphoramide, acetone and acetonitrile. The preferred
solvent is dimethylformamide. The reaction can be run at a
temperature from 0.degree. C. to ambient temperature, ambient
temperature being preferred.
[0053] Step B2: The silyl derivative 7 is then reacted with a
C.sub.1-4 alkyl lithium, such as n-butyl, sec-butyl or t-butyl
lithium, n-butyl lithium being preferred, in an ethereal solvent,
such as diethyl ether, tetrahydrofuran or dimethoxyethane, with
tetrahydrofuran being the preferred solvent. This results in the
regioselective formation of the anion. Addition of a suitable
N-protected piperidinyl Weinreb amide derivative 8, produces the
ketone 9. Suitable N-protecting groups (R.sub.2) are those that
would be stable under the reaction conditions, and examples can be
found in Protective Groups in Organic Synthesis, 2nd edition,
Theodora Greene, et al., John Wiley and Sons, Inc., incorporated
herein by reference. The reaction temperature may be varied between
-78.degree. C. to the boiling point of the solvent.
[0054] Step B3: The ketone 9 is N-deprotected to produce the aroyl
piperidine 10. Reagents and conditions to effect the deprotection
would depend upon the nature of the N-substituent and would be
apparent to one with ordinary skill in the art.
[0055] Step B4: Reaction of aroyl piperidine 10 with a suitable
alkylating agent 11 forms the alkylated piperidine 12. A suitable
alkylating agent is where X=a suitable leaving group. A "suitable
leaving group" is a moiety that is displaced or removed for the
reaction to take place. Examples of suitable leaving groups are
halogens, benzenesulfonate, methanesulfonate or p-toluenesulfonate,
with methanesulfonate being preferred. The reaction is performed in
the presence of a suitable organic base, in a polar aprotic
solvent. Examples of suitable organic bases are pyridine,
triethylamine, lutidine and N-ethyldiisopropylamine, with
N-ethyldiisopropylamine preferred. Examples of suitable polar
aprotic solvents are acetone, acetonitrile, dimethylformamide,
1-methyl-2-pyrrolidinone, dimethylsulfoxide and
hexamethylphosphoramide. The preferred solvent is acetonitrile. The
reaction may be conducted at room temperature to the boiling point
of the solvent. The preferred temperature being the boiling point
of the solvent.
[0056] Step B5: The alkylated piperidine 12 is converted to the
hydroxy ketone 13 by treatment with a suitable desilylating agent
in an ethereal solvent. A suitable desilylating agent is a
compound, which removes the silyl protecting group. Examples of
suitable desilylating agents are ammonium tetrafluoride,
tetra-N-butylammonium fluoride and pyridine hydrofluoride,
tetra-N-butylammonium fluoride being preferred. Suitable ethereal
solvents are diethyl ether, tetrahydrofuran or dimethoxyethane,
tetrahydrofuran being preferred. The reaction temperature may vary
from 0C to the boiling point of the solvent, with ambient
temperature being preferred.
[0057] Step B6: Hydroxy ketone 13 is converted to the intermediate
sulfuric acid ester 14 by reacting said hydroxyketone with a
suitable sulfating agent. Suitable sulfating agents are those
compounds capable of adding sulfate at the desired position.
Examples are sulfur trioxide pyridine complex, sulfur trioxide
triethylamine complex, sulfur trioxide dimethylformamide complex,
sulfuric acid-dicyclohexylcarbodiimide and chlorosulfonic acid with
acid or base. The reagent sulfur trioxide pyridine complex being
preferred. The reaction is carried out in an appropriate organic
solvent for the reaction to occur. Examples of appropriate organic
solvents are benzene, toluene, acetonitrile, dimethylformamide,
dichloromethane and chloroform. The preferred solvent is
acetonitrile. The reaction temperature may vary from room
temperature to boiling point of the solvent. The preferred
temperature being the boiling point of the solvent.
[0058] Step B7: Preferably without isolation, the sulfuric acid
ester ketone 14 is reduced to the racemic alcohol ester 15, by an
suitable reducing agent. A suitable reducing agent is a compound,
which reduces this ketone to the desired alcohol. Examples of
suitable reducing agents are alkali metal borohydrides, such as
lithium or sodium borohydride with sodium borohydride being the
preferred reducing agent. The reaction is performed in an
appropriate protic organic solvent such as ethanol, isopropanol,
propanol or methanol, ethanol being the preferred solvent. The
reaction temperature may vary from 0.degree. C. to the boiling
point of the solvent, with room temperature being preferred.
[0059] Step B8: Optionally reacting compound 15 or its enantiomers
with an inorganic or organic acid capable of forming a
pharmaceutically acceptable salt.
[0060] In another embodiment of this invention, the method of
synthesis of the intermediate alcohol 1 is described in Scheme C.
6
[0061] Step C1: The benzoyl piperidine 10 from Scheme B is reacted
with the acid halide 16 to obtain the ketoamide 17. The substituent
X represents a halogen chosen from Br, Cl and F with Cl being the
preferred halogen. The substituent R.sub.1 represents the group
Si(R.sub.3).sub.4 and R.sub.3 represents C.sub.1-4 alkyl. The
reaction can be performed under conditions that are well known to
one skilled in the art, for instance, in a suitable organic solvent
and in the presence of a suitable base. Examples of suitable
organic solvents are aromatic hydrocarbons such as benzene,
toluene, mesitylene and xylenes; aliphatic hydrocarbons such as
pentane, hexane and heptane and aliphatic ethers such as diethyl
and diisopropyl ether. The preferred solvent being toluene.
Suitable bases would be tertiary organic amines, and aqueous
solutions of inorganic bases. Inorganic bases suitable for use in
the present invention include alkali hydroxides, alkali carbonates
and alkali bicarbonates. Most preferred is an aqueous solution of
an alkali hydroxide such as sodium hydroxide.
[0062] Step C2: The ketoamide 17 is reduced to produce the
piperidine alcohol 18 as a racemate with a suitable reducing agent
in an organic solvent. Reducing agents suitable for use in the
method are borane complexes, aluminum hydrides, alkali aluminum
hydrides, alkali borohydrides particularly in the presence of Lewis
or organic acids. The preferred reducing agent is borane-methyl
sulfide complex. Organic solvents that can typically be used for
the reaction are ether, tetrahydrofuran, dimethoxyethane and
toluene, with toluene being preferred. The reaction temperature at
which the reaction can be run may vary from -50.degree. C. to the
boiling point of the solvent. Most preferred is a temperature of
about -30.degree. C. to room temperature.
[0063] In a further embodiment, the piperidine alcohol 18 can be
obtained in an enantioenriched state by the addition of a catalytic
amount of a chiral oxazaborolidine to Step C2 above. The use of
such reagents for the enantioselective reduction of ketones has
been illustrated in a review by Walbine S. et al., Tetrahedron
Asymmetry, 1992, 3, 1475-1504, incorporated herein by reference.
Suitable chiral oxazaborolidines for the reaction are (R) or
(S)-3,3-diphenyl-1-substituted
pyrrolidino[1,2-c]-1,3,2-oxazaboroles and (R) or (S)
-3,3-di-.beta.-naphthyl-1-substituted
pyrrolidino[1,2-c]-1,3,2-oxazaborol- es. The preferred chiral
catalyst being (R) or (S)-3,3-diphenyl-1-methylpy-
rrolidino[1,2-c]-1,3,2-oxazaborole (2-methyl-CBS-oxazaborolidine or
methyl oxazaborolidine).
[0064] Step C3: Optionally, the piperidine alcohol 18 can be
deprotected to produce the racemate of the phenol alcohol 1 by
treatment with a suitable desilylating agent in an organic solvent.
A suitable desilylating agent is a compound, which removes the
silyl protecting group. Examples of suitable desilylating agents
are ammonium tetrafluoride, tetra-N-butylammonium fluoride and
pyridine hydrofluoride, with ammonium tetrafluoride preferred.
Suitable organic solvents for the reaction are protic solvents such
as alcohols or ethereal solvents such as dialkylethers. The
reaction temperature may vary from ambient temperature to the
boiling point of the solvent.
[0065] Step C4: The piperidine alcohol 18 as a racemate or in
enantioenriched form can then be reacted with a suitable chiral
acid to give a mixture of diastereomeric esters 19, wherein R.sub.3
is a suitable resolving agent. Suitable resolving agent means a
moiety capable of separating enantiomers from a racemate by
formation of diastereomeric esters. Some examples of suitable
resolving agents are (R) or (S) mandelic acid, acetyl mandelic
acid, .alpha.-methoxyphenylacetic acid,
.alpha.-methoxy-.alpha.-(trifluoromethyl)-phenylacetic acid,
-2-(6-methoxy-2-naphthyl)-propionic acid, .omega.-camphanic acid,
trans-1,2-cyclohexane dicarboxylic acid anhydride and
5-oxo-2-tetrahydrofurancarboxylic acid as described in
Stereochemistry of Organic Compounds, Ernest L. Eliel et al., John
Wiley & Sons, Inc., incorporated herein by reference. The
preferred resolving agent is (R) or (S) .alpha.-methoxyphenylacetic
acid. The reaction is typically performed in an organic solvent in
the presence of a coupling promoter such as
dicyclohexylcarbodiimide or carbonyl diimidazole and a nucleophilic
catalyst such as imidazole or 4-dimethylamino-pyridine. The
preferred coupling promoter is dicyclohexylcarbodiimide, and the
preferred nucleophilic catalyst is 4-dimethylaminopyridine.
Suitable organic solvents for the reaction are aprotic solvents
such as chloroform, methylene chloride, dimethylformamide,
acetonitrile and toluene, with methylene chloride being preferred.
The reaction may be performed at room temperature to the boiling
point of the solvent, the boiling point of the solvent is the
preferred temperature. The mixture of diastereomeric esters is then
separated by techniques that are well known to one with ordinary
skill in the art, to produce the two individual diastereomers of
compound 19. Separation of the diastereomers, for example, can be
accomplished by crystallization or column chromatography, with the
preferred method of separation being chromatography.
[0066] Step C5: The pure individual diastereomer of 19 is converted
to the phenol ester 20 by treatment with a suitable desilylating
agent in a protic solvent. Examples of suitable desilylating agents
are ammonium tetrafluoride tetra-N-butylammonium fluoride and
pyridine hydrofluoride, with ammonium tetrafluoride preferred.
Suitable protic solvents are methanol, ethanol, propanol, butanol
and isopropanol, methanol being preferred. The reaction temperature
may vary from ambient temperature to the boiling point of the
solvent, the boiling point of the solvent being preferred.
[0067] Step C6: The phenol ester 20 is hydrolyzed to a single
enantiomer of the phenol alcohol 1 by reaction of the ester with a
suitable base in a water-protic solvent solution. Suitable bases to
effect the reaction are alkali metal hydroxides and carbonates,
such as sodium, potassium, lithium and cesium hydroxides and
carbonates, with the preferred base for the reaction being
potassium carbonate. Suitable water-protic solvent solutions are
methanol-water, ethanol-water, propanol-water, isopropanol-water
and butanol-water, with methanol-water preferred. The reaction
temperature may vary from 0.degree. C. to the boiling point of the
solvent, with a temperature of about 20-25.degree. C.
preferred.
[0068] Also, as a further embodiment of the invention compound 1
can be isolated as an acid addition salt, whose preparation can be
accomplished by methods that are well known to one with ordinary
skill in the art.
[0069] The compounds of the current invention may be isolated from
a sample such as human plasma by taking a sample of said human
plasma from a patient that has been administered a therapeutically
effective amount of
(+)-.alpha.-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperi-
dinemethanol, treating the sample by methods well-known to one with
ordinary skill in the art, and subjecting said sample to isolation
techniques such as chromatography. Chromatography of the sample can
be accomplished, for example, by such techniques as high
performance liquid chromatography, column chromatography, thin
layer chromatography and gas chromatography. The most preferred
method of isolation is high performance liquid chromatography.
[0070] The stereochemistry of the isolated compound will be
dependent upon the metabolic process, and thus may be isolated from
the patient as a racemate or a single enantiomer.
[0071] The dosage range at which sulfuric acid mono
-[3-({1-[2-(4-fluoro-phenyl) ethyl]-piperidin-4-yl
}-hydroxy-methyl)-2-methoxy-phenyl]ester and its enantiomers
exhibit their ability to block the effects of serotonin at the
5HT.sub.2A receptor can vary depending upon the particular disease
or condition being treated and its severity, the patient, other
underlying disease states the patient is suffering from, and other
medications that may be concurrently administered to the patient.
Generally though, the compounds will exhibit their serotonin
5HT.sub.2A antagonist properties at a dosage range of from about
0.001 mg/kg of patient body weight/day to about 100.0 mg/kg of
patient body weight/day. These compounds are typically administered
from 1-4 times daily. Alternatively, they can be administered by
continuous infusion. The compounds can be administered orally or
parenterally to achieve these effects.
[0072] The compound of the present invention intended for
administration can be formulated into pharmaceutical dosage forms
using techniques well known in the art. For oral administration,
the compound can be formulated into solid or liquid preparations
such as capsules, pills, tablets, lozenges, melts, powders,
suspensions, or emulsions. Solid unit dosage forms can be capsules
of the ordinary gelatin type containing, for example, surfactants,
lubricants and inert fillers such as lactose, sucrose, and
cornstarch or they can be sustained release preparations. In
another embodiment, the compound can be tableted with conventional
tablet bases such as lactose, sucrose, and cornstarch in
combination with binders, such as acacia, cornstarch, or gelatin,
disintegrating agents such as potato starch or algenic acid, and a
lubricant such as stearic acid or magnesium stearate. Liquid
preparations are prepared by dissolving the active ingredient in an
aqueous or non-aqueous pharmaceutically acceptable solvent, which
may also contain suspending agents, sweetening agents, flavoring
agents, and preservative agents as are known in the art.
[0073] For parenteral administration, the compound or its salts may
be dissolved in a physiologically acceptable pharmaceutical carrier
and administered as either a solution or a suspension. Illustrative
of suitable pharmaceutical carriers are water, saline, dextrose
solutions, fructose solutions, ethanol, or oils of animal,
vegetative, or synthetic origin. The pharmaceutical carrier may
also contain preservatives, buffers, etc. as are known in the
art.
[0074] The compound may be admixed with any inert carrier and
utilized in laboratory assays in order to determine the
concentration of the compounds within the urine, serum, etc. of the
patient as is known in the art.
[0075] The following examples present typical syntheses as
described by Schemes A, B and C and methods for isolation and
biological assays. These examples are understood to be illustrative
only and are not intended to limit the scope of the invention in
any way. As used in the following examples, the following terms
have the meanings indicated: "g" refers to grams, "mg" refers to
milligrams "mmol" refers to millimoles, mol refers to moles, "mL"
refers to milliliters, ".mu.L" refers to microliters ".mu.m" refers
to micromoles, ".mu.M" refers to micromolar, "mM" refers to
millimolar "ppm" refers to parts per million, "C" refers to
Celsius, "THF" refers to tetrahydrofuran, "MeOH" refers to
methanol, "EtOAc" refers to ethyl acetate, "TLC" refers to thin
layer chromatography, "LC" or "HPLC" refers to high performance
liquid chromatography and "CIMS" refers to chemical ionization mass
spectrum, "CIDMS" refers to collision-induced dissociation mass
spectrum, "NMR" refers to nuclear magnetic resonance, "IR" refers
to infrared spectroscopy "t.sub.R" means retention time, "R.sub.f"
means the ratio of the distances which the sample migrates (on TLC)
as compared to the distance from the starting point of the solvent
front.
EXAMPLE 1A
[0076] 7
2-(4-Fluoro-phenyl)-
1-[4-(2-methoxy-3-triisopropylsilanyloxy-benzoyl)-pip- eridin-
1-yl]-ethanone
[0077] To a solution of
4-(2-methoxy-3-triisopropylsilanyloxy-benzoyl)-pip- eridine of
Example 2C below (287 g, 0.72 mol) in toluene (750 mL) add 50% NaOH
(102 mL) and H.sub.2O (300 mL). Cool the mixture in an ice bath and
add 4-fluorophenacetyl chloride (221.3 g, 1.28 mol) dissolved in
toluene over a period of 30 min. Allow the reaction to warm to room
temperature, and stir for 2 h. Add H.sub.2O (500 mL), stir for 0.5
h and separate the phases. Dry the organic layer (MgSO.sub.4) and
concentrate to obtain 482 g of a brown oil. Purify the oil by flash
chromatography over silica gel in three separate portions, eluting
with ethyl acetate/hexanes. Combine like fractions to obtain two
batches of oil: 123 g and 269 g. Treat the smaller batch with 1:9
ethyl acetate/hexane and filter away 28 g of 4-flurorophenyl acetic
acid. Concentrate the filtrate to obtain 95 g of oil, combine with
the larger batch and dissolve in 1:1 ethyl acetate/hexane (1.5 L).
Wash the organic solution with 4% NaOH (1 L), 2% NaOH (1 L), 2% HCl
(1 L), saturated NaHCO.sub.3 (1 L) and H.sub.2O (1 L). Dry the
organic layer (MgSO.sub.4), filter and concentrate to obtain 270 g
of the title compound.
EXAMPLE 1B
[0078] 8
{1-[2-(4-Fluoro-phenyl)-ethyl]-piperidin-4-yl}-(2-methoxy-3-triisopropylsi-
lanyloxy-phenyl)-methanol
[0079] To a solution of
2-(4-Fluoro-phenyl)-1-[4-(2-methoxy-3-triisopropyl-
silanyloxy-benzoyl)-piperidin-1-yl]-ethanone, Example 1A (262 g,
0.496 mol) in toluene (3.8 L) at -38.degree. C. add
(R)-methyloxoazaborolidine (150 mL, 0.15 mol, of 1M solution in
toluene), follow with the addition of borane dimethylsulfide
complex (750 mL of a 2M solution in toluene, 1.5 mol), over a 2 h
period at -30.degree. C. Stir between -25.degree. C. to -28.degree.
C. overnight and then allow the reaction to warm to ambient
temperature over a 2 h period. Slowly add MeOH (500 mL) over a1 h
period and then concentrate the solution to obtain 363 g of yellow
oil. Add MeOH (1.8 L) to the oil and concentrate under reduced
pressure at 80.degree. C. to obtain 341 g of a yellow oil. Purify
the oil by plug filtration through silica gel eluting with 1:1
MeOH/CHCl.sub.3. Combine and concentrate the desired fractions to
obtain 250 g of product. Further purify the product by column
chromatography over silica gel eluting with 1:3 EtOAc/hexane (20
L), 1:1 EtOAc/hexane (20 L) and 1:1 CHCl.sub.3/MeOH (40 L). Collect
and concentrate like fractions to obtain 214 g of oil. Dissolve the
oil in CHCl.sub.3 (500 mL)/toluene (600 mL), dry (MgSO.sub.4) and
concentrate to obtain 207 g of the title compound as a foam.
EXAMPLE 1C
[0080] 9
(S)-Methoxy-2-phenyl-acetic acid
{1-[2-(4-fluoro-phenyl)-ethyl]-piperidin-- 4-yl
}-(2-methoxy-3-triisopropylsilanyloxy-phenyl)-methyl ester
[0081] Stir a solution of {1
-[2-(4-fluoro-phenyl)-ethyl]-piperidin-4-yl}--
(2-methoxy-3-triisopropylsilanyloxy-phenyl)-methanol, Example 1B
(233.5 g, 0.53 mol) in CHCl.sub.3 (2 L), add
(S)-(+)-.alpha.-methoxyphenyl acetic acid (91 g, 0.55 mol) in
CH.sub.2Cl.sub.2 (40 mL) 1,3-dicyclohexylcarbodi- imide (11.2 g,
0.54 mol) and 4-dimethylaminopyridine (0.3 g, 0.008 mol). Heat the
reaction to reflux for 17 h, cool in an ice bath and add hexane (1
L). Filter the mixture to remove the by-product urea and
concentrate to obtain 368 g of yellow oil. Add hexane (1.4 L) to
the oil and heat to dissolve. Cool the solution to ambient
temperature and allow standing for 24 h. Filter off more urea and
concentrate the filtrate with 630 g of silica gel. Apply the coated
silica gel to a column previously packed with silica gel and elute
with 1:5 EtOAc/hexane (80 L) and 1:2 EtOAc/hexane (20 L).
Concentrate like fractions and obtain a semi-solid. Treat the
semi-solid with hexane and filter away the last traces of the urea.
Concentrate the filtrate to obtain 207.2 g of yellow oil.
EXAMPLE 1D
[0082] 10
(S)-Methoxy-2-phenyl-acetic acid
{1-[2-(4-fluoro-phenyl)-ethyl]-piperidin4- -yl
}-(3-hydroxy-2-methoxy-phenyl)-methyl ester
[0083] Add to methoxy-phenyl-acetic acid
{1-[2-(4-fluoro-phenyl)-ethyl]-pi-
peridin-4-yl}-(2-methoxy-3-triisopropylsilanyloxy-phenyl)-methyl
ester, Example 1C (207 g, 0.3111 mol) a 0.5M solution of methanolic
ammonium tetrafluoride (1.2 L, 0.6 mol) and reflux for 17.5 h.
Concentrate and obtain 198 g of the title compound.
EXAMPLE 1E
[0084] 11
(+)-1-
[2-(4-Fluorophenyl-)ethyl]-.alpha.-(3-hydroxy-2-methoxyphenyl)-pipe-
ridinemethanol
[0085] Add to a solution of methoxy-phenyl-acetic acid
{1-[2-(4-fluoro-phenyl)-ethyl]-piperidin-4-yl}-(3-hydroxy-2-methoxy-pheny-
l)-methyl ester, Example 1D (158.2 g, 0.311 mol) in MeOH (1.2 L),
K.sub.2CO.sub.3 (96.2 g, 0.676 mol). Stir the reaction mixture at
ambient temperature for 16 h add H.sub.2O (163 mL) and continue to
stir for 16.5 h. Cool the reaction to ambient temperature and
concentrate. Stir the residue in CHCl.sub.3 (1.5 L)-H.sub.2O (1 L)
for 10 min and separate the organic layer. Wash the organic phase
with H.sub.2O (500 mL), dry (MgSO.sub.4) and concentrate to 140 g
of white foam. Purify the product by flash chromatography over
silica gel eluting with 1.5:1 CHCl.sub.3/MeOH (40 L) and
CHCl.sub.3/MeOH (20 L). Combine and concentrate like fractions and
dissolve the residue in EtOAc (1 L). Dry the solution (MgSO.sub.4)
and concentrate to obtain 86 g of the product as a white foam.
[.alpha.].sub.D (c=1.0, in methanol)=+25.30.
EXAMPLE 1F
[0086] 12
Acetic
acid-(3-acetoxy-2-methoxy-phenyl)-{1-[2-(4-fluoro-phenyl)-ethyl]-pi-
peridin-4-yl }-methyl ester
[0087] Add acetic anhydride (5 mL), dropwise, over 10 min to a
stirring, cooled (ice/water bath) solution of
(+)-1-[2-(4-fluorophenyl-)ethyl]-.alp-
ha.-(3-hydroxy-2-methoxyphenyl)-piperidinemethanol, Example 1E (4.0
g, 11.1 mmol) in pyridine (40 mL). Stir the reaction mixture
overnight, while allowing the temperature to rise to ambient
temperature. Add dichloromethane (100 mL) and wash the organics
twice with aqueous bicarbonate solution (100 mL). Dry the organic
layer over Na.sub.2SO.sub.4, filter and evaporate under vacuum and
obtain 5.2 g of product.
EXAMPLE 1G
[0088] 13
Acetic
acid-{1-[2-(4-fluoro-phenyl)-ethyl]-piperidin-4-yl}-(3-hydroxy-2-me-
thoxy-phenyl)-methyl ester
[0089] Stir overnight a mixture of the acetic acid
-(3-acetoxy-2-methoxy-p- henyl)-{
1-[2-(4-fluoro-phenyl)-ethyl]-piperidin-4-yl}-methyl ester, Example
1F (5.2 g, 1.1 mmol), NaHCO.sub.3 (11 g, 130 mmol), methanol (100
mL) and water (50 .mu.L). Add water (100 mL) and dichloromethane
(100 mL), and separate the layers. Extract the aqueous layer with
dichloromethane (100 mL), and combine the organic layers. Dry over
Na.sub.2SO.sub.4 and filter. Remove the solvent under vacuum and
obtain 5.1 g of product.
EXAMPLE 1H
[0090] 14
Sulfuric acid mono-(+)-[3-(-{1
-[2-(4-fluoro-phenyl)-ethyl]-piperidin-4-yl
}-hydroxy-methyl)-2-methoxy-phenyl]ester
[0091] Add sulfur trioxide pyridine complex (10 g, 62 mmol) to a
solution of the acetic
acid-{1-[2-(4-fluoro-phenyl)-ethyl]-piperidin-4-yl}-(3-hydr-
oxy-2-methoxy-phenyl)-methyl ester, Example 1G (5.1 g, 11.1 mmol)
in acetonitrile (50 mL), and heat at 45.degree. C. for 18 h. Cool
the mixture to ambient temperature and add water (70 mL), methanol
(70 mL) and K.sub.2CO.sub.3 (26 g, 0.194 mol). Reflux the mixture
for 12 h. Evaporate the acetonitrile and methanol and acidify the
remaining aqueous portion to pH=6. Collect the resulting
precipitate, rinse with water and dry to obtain 3.0 g of a light,
brown solid. The solid is 98% pure by LC (Zorbax Rx C8, 5.mu.,
250.times.4.6 mm, 0.17M acetic acid-0.05M ammonium acetate
buffer/acetonitrile, 75:25. Flow: 0.8 mL/min) t.sub.R=9.40 min.
CIMS, m/z=342 (M+H--SO.sub.3--H.sub.2O).sup.+. .sup.1H NMR (300
MHz, DMSO-d.sub.6) .delta. (ppm) 7.40 (d, 1H), 7.35 (t, 2H), 7.12
(t, 2H), 7.00 (d, 1H), 6.95 (d, 2H), 4.95 (s, 1H), 4.63 (t, 1H),
3.79 (s, 3H), 3.50-2.40 (series of broad peaks, 9H), 1.90-1.40
(series of broad peaks, 5H). .sup.13C NMR (75 MHz, DMSO-d.sub.6)
.delta.=162.25, 159.95, 147.75, 145.59, 137.02, 130.05, 122.20,
121.5, 119.95, 115.05, 115.00, 69.03, 60.09, 57.00, 52.00, 33.33,
29.02, 26.02, 25.00, 24.05. .sup.19F NMR (376 MHz, DMSO-d.sub.6)
.delta.=-117.00. [.alpha.].sub.D (22.degree. C., c=0.6033 in 2:1
DMSO/MeOH)=+28.90.
EXAMPLE 2A
[0092] 15
2-Methoxy-1-(triisopropylsilyloxy)benzene
[0093] To a solution, under nitrogen, of guiacol (1.0 g, 8.06 mmol)
in DMF (20 mL) at ambient temperature add imidazole (1.15 g, 16.9
mmol) and triisopropylsilyl chloride (2.6 mL, 12.08 mmol). Allow
reaction for 23.5 h and then pour into saturated NaHCO.sub.3
solution (35 mL). Extract the aqueous mixture with hexane
(3.times.50 mL), combine the extracts, wash with 1M HCl (50 mL),
H.sub.2O (50 mL) and dry over MgSO.sub.4. Filter through
Na.sub.2SO.sub.4 and concentrate under vacuum. Distill the product
with a Kugelrohr apparatus under high vacuum and collect 2.14 g of
colorless oil.
[0094] Anal. Calc. for C.sub.16H.sub.28O.sub.2Si: C, 68.50; H,
10.08. Found: C, 68.45; H, 9.92. CIMS (CH.sub.4): m/z=281 (81%),
237 (100%). IR (KBr): 2945, 2868, 1504, 1458, 1282, 1267, 920, 745
cm.sup.-1. .sup.1H NMR (CDCl.sub.3): .delta. 6.90-6.75 (4 H), 3.79
(3 H, s), 1.32-1.19 (1 H, m), 1.09 (6 H, d, J=7.1 Hz). .sup.13C NMR
(CDCl.sub.3): .delta. (ppm) 150.9, 145.5, 121.3, 120.7, 120.5,
112.2, 55.4, 17.9, 12.9.
EXAMPLE 2B
[0095] 16
4-(2-Methoxy-3-triisopropylsilanyloxy-benzoyl)-piperidine-1-carboxylic
acid tert-butyl ester
[0096] Cool in a dry ice/acetone bath under nitrogen, a solution of
2-methoxy-1-(triisopropylsilyloxy)benzene, Example 2A (0.560 g,
2.00 mmol) in dry THF (5.0 mL) and add 2.5M n-butyllithium in
hexane (3.2 mL, 8.0 mmol) over 5 minutes. After 10 minutes more
allow the reaction to warm to 0.degree. C., then after 4 hours, to
20.degree. C. for 2h, and then to reflux for 0.5 hour. Cool the
reaction to -78.degree. C. and treat with neat
4-(N-methoxy-N-methylcarboxamido)-1-piperidinecarboxylic acid
tert-butyl ester (prepared as described in U.S. Pat. No. 5,134,139)
(0.653 g, 2.40 mmol). Allow the reaction to warm to 20.degree. C.
After 16 h, treat the reaction with saturated NH.sub.4Cl/H.sub.2O
(2 mL) and water (10 mL) and extract with CH.sub.2Cl.sub.2
(2.times.20 mL). Dry the combined extracts (Na.sub.2SO.sub.4),
concentrate under vacuum, and chromatograph over silica gel eluting
initially with 10:90 ethyl acetate/hexane, and then 20:80 ethyl
acetate/hexane, isolating the component with an R.sub.f.about.0.35
in the latter system. Remove the unreacted guaiacol contaminant
from a CH.sub.2Cl.sub.2 solution of the chromatographed material
with a 1M NaOH/H.sub.2O wash to obtain the title compound as an oil
(0.543 g, 55%).
[0097] Anal. Calc. for C.sub.27H.sub.45NO.sub.5Si: C, 65.95; H,
9.22; N, 2.85. Found: C, 66.01; H, 9.15; N, 3.02. CIMS (CH.sub.4):
m/z=492 (8%), 436 (100%), 392 (25%). IR (KBr): 2945, 2868, 1697,
1471, 1423, 1280, 1173cm.sup.-1. .sup.1H NMR (CDCl.sub.3): .delta.
(ppm) 6.94(3H,m), 4.06 (2H, bd),3.84 (3 H, s), 3.23 (1 H, tt,
J=11.2, 4.0Hz), 2.85 (2 H, bt, J=12.2 Hz), 1.84(2 H, dd, J=13.2,
3.0 Hz), 1.59(2 H, m), 1.45(9 H, s), 1.30(3 H, m), 1.12(18 H, d,
J=7.1 Hz). .sup.13C NMR (CDCl.sub.3): .delta. 206.1, 154.7, 149.4,
148.8, 134.7, 124.1, 123.2, 120.8, 79.4, 61.6, 47.8, 43.3 (broad),
28.4, 27.8, 17.8, 12.8.
EXAMPLE 2C
[0098] 17
{1-[2-(4-Fluoro-phenyl)-ethyl]-piperidin-4-yl}-(2-methoxy-3-triisopropylsi-
lanyloxy-phenyl)-methanone
[0099] Stir and cool in an ice bath under nitrogen,
4-(2-methoxy-3-triisopropylsilanyloxy-benzoyl)-piperidine-1-carboxylic
acid tert-butyl ester, Example 2B (5.71 g, 11.6 mmol) and add
trifluoroacetic acid (30 mL). Remove the cold bath after 10
minutes. After 2 h, concentrate the reaction under vacuum at
40-45.degree. C. and then pour into saturated aqueous NaHCO.sub.3.
Extract the basic layer with CH.sub.2Cl.sub.2 (2.times.200 mL), dry
(Na.sub.2SO.sub.4), and concentrate under vacuum to an oil, which
eventually solidifies to afford
4-(2-methoxy-3-triisopropylsilanyloxy-benzoyl)-piperidine.
[0100] Dissolve the crude amine from above in dry acetonitrile (60
mL), treat with diisopropylethylamine (4.9 mL, 28.2 mmol) and add
2-(4-fluorophenyl)ethyl-1-mesylate, (synthesis is described in U.S.
Pat. No. 4,221,817) (3.07 g, 14.1 mmol). Heat the reaction at
reflux under nitrogen for 24 hours, cool, treat with saturated
aqueous NaHCO.sub.3 (50 mL), and extract with CH.sub.2Cl.sub.2 (150
mL). The combined extracts were dried (MgSO.sub.4) and concentrated
under vacuum to an oil. Purify the product by column chromatography
over silica gel, eluting with 30:70 ethyl acetate/hexane to give
4.72 g (80%) of oil (Rf.about.0.3 streaking).
[0101] Anal. Calc. for C.sub.30H.sub.44FNO.sub.3Si: C, 70.13; H,
8.63; N, 2.73. Found: C, 70.03; H, 8.52; N, 2.88. CIMS (CH.sub.4):
m/z=514 (70%), 404 (100%). IR (neat): 2945, 2868, 1690, 1510, 1470,
1296, 1222,956 cm.sup.-1. .sup.1H NMR (CDCl.sub.3): .delta. (ppm)
7.17-7.11(2 H, m), 6.97-6.91(5 H), 3.84 (3 H, s), 3.08 (1 H, m),
2.97 (2 H, m), 2.76 (2 H, dd), 2.55 (2 H, dd), 2.10 (2 H, dt), 1.91
(2 H, bd), 1.80-1.68 (2 H), 1.37-1.24 (3 H, m), 1.10 (18 H).
.sup.13C NMR (CDCl.sub.3): .delta. 206.6, 162.9, 159.7, 149.4,
148.7, 136.1, 135.0, 130.0, 129.9, 124.1, 123.0, 120.8, 115.2,
114.9, 61.5, 60.7, 53.2, 47.9, 32.9, 28.1, 17.9, 12.8. .sup.19F NMR
(CDCl.sub.3): .delta. -118.061 (m).
EXAMPLE 2D
[0102] 18
{1-[2-(4-Fluoro-phenyl)-ethyl]-piperidin-4-yl}-(3-hydroxy-2-methoxy-phenyl-
)-methanone
[0103] Add to a solution of
{1-[2-(4-fluoro-phenyl)-ethyl]-piperidin-4-yl}-
-(2-methoxy-3-triisopropylsilanyloxy-phenyl)-methanone, Example 2C
(1.80 g, 3.50 mmol) in dry THF (5 mL) at ca. 20.degree. C. under
nitrogen, 1.0 M tetrabutylammonium fluoride in THF (4.55 mL, 4.55
mmol). After stirring 5 h, dilute the reaction with brine (100 mL)
and extract with CH.sub.2Cl.sub.2 (3.times.75 mL). Dry the extracts
(Na.sub.2SO.sub.4) and concentrate under vacuum. Purify the crude
product by column chromatography over silica gel eluting initially
with 50:50 ethyl acetate/hexane then 5:95 methanol/ethyl acetate
giving the product as an oil (R.sub.f.about.0.2 in ethyl acetate),
which solidifies after standing. Triturate the solid with hexanes
and recrystallize from hot ether (.about.30 mL) by cooling and
concentrating under a nitrogen stream to .about.10 mL. Collect the
resulting slightly orange crystals to obtain 1.04 g (83 %) of the
title compound, mp 100-101.degree. C.
[0104] Anal. Calc. for C.sub.21H.sub.24FNO.sub.3: C, 70.57; H,
6.77; N, 3.92. Found: C, 70.24; H, 6.72; N, 4.03. CIMS (CH4):
m/z=358 (100%), 338 (28%), 248 (96%). IR (KBr): 3437, 2957, 1684,
1510, 1221 cm.sup.-1. .sup.1H NMR (CDCl.sub.3): .delta. (ppm) 7.14
(2 H, m), 7.06 (1 H, s), 7.04 (1 H, d, J=2.1 Hz), 6.95 (3 H, m),
3.81(3 H, s), 3.09(1 H, m), 3.01(2 H, m), 2.77 (2 H, dd, J=9.3,
11.0 Hz), 2.57 (2 H, m), 2.14 (2 H, dt, J=2.3, 11.4 Hz), 1.82 (4 H,
m). .sup.13C NMR (CDCl.sub.3): .delta. 205.5, 163.0, 159.7, 149.3,
145.2, 135.9, 135.9, 132.8, 130.0, 129.9, 124.8, 120.1, 118.7,
115.2, 114.9, 62.8, 60.6, 53.2, 47.3, 32.7, 28.1. .sup.19FNMR
(CDCl.sub.3): .delta. -117.913(m).
EXAMPLE 2E
[0105] 19
Sulfuric acid
mono-(.+-.)-[3-({1-[2-(4-fluoro-phenyl)-ethyl]-piperidin-4-y-
l}-hydroxy-methyl)-2-methoxy-phenyl]ester
[0106] To a 7 mL glass screw cap tube add acetonitrile (200 .mu.L),
pyridine (200 .mu.L), sulfur trioxide pyridine complex (20 mg, 130
.mu.m) and {
1-[2-(4-fluoro-phenyl)-ethyl]-piperidin-4-yl}-(3-hydroxy-2-methoxy--
phenyl)-methanone, Example 2D (5.2 g, 15.2 .mu.m). Place on a
heating block and heat at 100.degree. C. for 2h. Cool and
concentrate under vacuum (Savant concentrator), and dissolve
residue in absolute ethanol (0.5mL). Add NaBH.sub.4 (30 mg) and
then quench with acetic acid (100 .mu.L). Dilute the reaction
mixture 1/40 with 20:80 acetonitrile/buffer (0.17M acetic acid with
0.5M ammonium acetate) and analyze by LC/MS/MS (Zorbax RX , C8,
5.mu.m, 2.1.times.150 mm, buffer: 0.17M acetic acid and 0.05M
ammonium acetate/acetonitrile; 75/25, Flow: 0.15 mL/min)
t.sub.R=6.83 min. CIDMS m/z=440 (M+H.sup.)+. .sup.1H NMR (300 MHz,
DMSO-d.sub.6) .delta. (ppm) =7.40 (d, 1H), 7.35 (t, 2H), 7.12 (t,
2H),7.00 (d, 1H), 6.95 (d, 2H), 4.95 (s, 1H), 4.63 (t, 1H), 3.79
(s, 3H), 3.50-2.40 (series of broad peaks, 9H), 1.90-1.40 (series
of broad peaks, 5H). .sup.13C NMR (75 MHz, DMSO-d.sub.6) .delta.
(ppm)=162.25, 159.95, 147.75, 145.59, 137.02, 130.05, 122.20,
121.5, 119.95, 115.05, 115.00, 69.03, 60.09, 57.00, 52.00, 33.33,
29.02, 26.02, 25.00, 24.05. .sup.19F NMR (376 MHz, DMSO-d.sub.6)
.delta. (ppm)=-117.00.
[0107] The compounds of the present invention antagonize the
effects of serotonin at the human 5-HT.sub.2A-type serotonin
receptor as shown by standard binding data. Conversely, the
compounds of the present invention do not show any significant
affinity at the following human receptors: dopamine-D.sub.2;
serotonin-5HT.sub.2C; alpha adrenergic-.alpha..sub.1A as shown by
standard binding methods.
EXAMPLE 3
Receptor Binding Assays
[0108] Cells stably expressing the human homologs of the receptors
(dopamine D.sub.2L, serotonin 5HT.sub.2A and 5HT.sub.2C,
.alpha..sub.1A adrenergic; cloned and expressed at Hoechst Marion
Roussel; Grandy et al., 1989; Monsma et al., 1993; Schwinn et al.,
1995) were grown; cell membranes were prepared, and kept frozen
until used (Kongsamut et al., 1996). The relevance of these binding
sites has been extensively discussed in the literature (see for
example: Carlsson & Carlsson, 1990; Creese et al., 1976; Gorman
& Vargas, 1995; Meltzer et al., 1989). All binding parameters
were optimized at Hoechst Marion Roussel; ligand K.sub.ds were
determined using both saturation analysis (Scatchard) as well as
kinetic analysis (association and dissociation rates). Each batch
of membrane was validated by checking the ligand K.sub.d, and rank
order of potency of selected standard compounds. Assays for the
serotonin 5HT.sub.2A and dopamine D.sub.2L receptors were conducted
at 37.degree. C. in a Tris buffer containing salts (50 mM Tris
Buffer, pH 7.7; 120 mM NaCl; 5 mM KCl; 2 mM CaCl.sub.2; 1 mM
MgCl.sub.2), while the serotonin 5-HT.sub.2C and .alpha.1A
adrenergic receptor assays used a different buffer without salts
(50 mM Tris, 4 mM CaCl.sub.2 and 1% ascorbate, pH 7.4). Various
binding parameters (ligand, ligand concentration, incubation times,
ligand K.sub.ds, displacing agent to define specific binding and
tissue/cell line used) are summarized in the Table below (Closse et
al., 1983; Hall et al., 1990; Leysen et al., 1977).
[0109] Membranes were rapidly thawed and diluted to an appropriate
concentration (between 20-150 .mu.g protein/assay point depending
on receptor expression level) in Tris buffer and homogenized. Assay
plates were incubated at 37.degree. C. in an incubator for the
times indicated. The assay was stopped by rapid filtration and
washing (15 mL ice-cold 0.05M Tris buffer, pH 7.7) through Packard
GF/B Unifilter plates (presoaked in 0.5% polyethyleneimine) using a
Tomtec 96-well Cell Harvestor. Microscint scintillation cocktail
(40 .mu.l) were added and the filter plates were counted in a
Packard Top Count scintillation counter. Data were analyzed to
determine Ki's for compounds of interest (Prusoff & Cheng, 19).
Table: Receptor Binding Parameters. All Scatchard analyses with the
ligands below showed a single site; displacement of the ligands was
assumed to be single site displacements.
1 ligand [conc.] incubation time ligand Kd non-specific receptor
ligand (nM) (min) (nM) binding cell/tissue human
[.sup.3H]N-methylspiperone 1 60 0.09 10 .mu.M CHO D.sub.2L
(-)eticlopride human [.sup.3H]N-methylspiperone 1.5 40 0.92 30
.mu.M BHK 5-HT.sub.2A methysergide human [.sup.3H]mesulergine 2 40
1.9 100 nM CHO 5-HT.sub.2C mianserin human [.sup.3H]prazosin 1 40
0.19 10 .mu.M CHO .alpha..sub.1A phentolamine
[0110] References:
[0111] 1. Carlsson, M., Carlsson, A. Interactions between
glutamatergic and monoaminergic systems within the basal
ganglia--implications for schizophrenia and Parkinson's disease.
Trends Neural Sci 13: 272-276, 1990.
[0112] 2. Closse, A. M. [.sup.3H]Mesulergine, a selective ligand
for 5HT.sub.2 receptors. Life Sci. 32: 2485-2495, 1983.
[0113] 3. Creese, I., Burt, D. R., Snyder S. H. Dopamine receptor
binding predicts clinical and pharmacological potencies of
antischizophrenic drugs. Science 192: 481-483, 1976.
[0114] 4. Grandy, D. K., Marchionni, M. A., Makam, H., Stofko, R.
E., Alfano, M., Frothingham, L., Fischer, J. B., Burke-Howie, K.
J., Bunzow, J. R., Server, A. C. and Civelli, O. Cloning of the
cDNA and gene for a human D.sub.2 dopamine receptor. Proc. Nat.
Acad. Sci. U.S.A. 86: 9762-9766, 1989.
[0115] 5. Hall, H., Wedel, I., Halldin, C., Kopp, J & Farde, L.
Comparison of the in vitro Receptor Binding Properties of
N-[.sup.3H]Methylspiperone and [.sup.3H]raclopride to Rat and Human
Brain Membranes. J. Neurochem. 55: 2048-2057, 1990.
[0116] 6. Kongsamut, S., Roehr, J. E., Cai, J., Hartman, H. B.,
Weissensee, P., Kerman, L. L., Tang, L. & Sandrasagra, A.
Iloperidone binding to human and rat dopamine and serotonin
receptors. Eur J Pharmacol 317: 417423, 1996.
[0117] 7. Leysen, J. E., Gommeren, W. & Laduron, P. M.
Spiperone: A ligand of choice for neuroleptic receptors. Biochem.
Pharmacol. 27: 307-328 (1977).
[0118] 8. Meltzer, H. Y. Clinical studies on the mechanism of
action of clozapine: the dopamine-serotonin hypothesis of
schizophrenia. Psychopharmacol 99: S18-S27, 1989.
[0119] 9. Monsma, F. J., Jr, Shen, Y., Ward, R. P., Hamblin, M. W.
& Sibley, D. R. Cloning and expression of a novel serotonin
receptor with high affinity for tricyclic psychotropic drugs.
Molec. Pharmacol. 43: 320-327, 1993.
[0120] 10. Schmidt, C., Sorensen S. M., Kehne, J. H., Carr, A. A.
& Palfreyman, M. G. The role of 5HT.sub.2A receptors in
antipsychotic activity. Life Sci. 56: 2209-2222, 1995.
[0121] 11. Schwinn, D. A., Johnston, G. I., Page, S. O., Mosley, M.
J., Wilson, K. H., Worman, N. P., Campbell, S., Fidock, M. D.,
Furness, L. M., Parry-Smith, D. J., et al. Cloning and
pharmacological characterization of human alpha-1 adrenergic
receptors: sequence corrections and direct comparison with other
species homologues. J. Pharmacol. Exp. Ther. 272:134-142, 1995.
[0122] 12. Vargas, H. M. & Gorman, A. J. Vascular alpha-1
adrenergic receptor subtypes in the regulation of arterial
pressure. Life Sci. 57: 2291-2308, 1995.
[0123] All of the forgoing references are incorporated herein by
reference.
[0124] In vitro inhibition of [.sup.3H]-Ligand binding to human
.sup.5-HT2A, D.sub.2, .sup.5HT.sub.2C and .alpha..sub.1A
receptors
2 Compound 5HT.sub.2A (K.sub.i .mu.M) D.sub.2 (K.sub.i .mu.M)
5HT.sub.2C (K.sub.i .mu.M) .alpha..sub.1A (K.sub.i .mu.M) Example
1H 0.16 >1.0 >1.0 >1.0
[0125] The compounds of this invention are capable of crossing the
blood-brain barrier (BBB) as shown by their ability to penetrate
across a membrane of a monolayer of bovine brain microvessel
endothelial cells, an in vitro model for BBB permeability.
EXAMPLE 4
Bovine Brain Endothelial Cells (BBMEC) Transport Studies
[0126] The procedure was performed according to: Kenneth L. Audus
et al., Brain Microvessel Endothelial Cell Culture System (Chapter
13) pp 239-258. In Models for Assessing Drug Absorption and
Metabolism, Ronald T. Borchardt et al. eds., Plenum Press, New York
1996, incorporated herein by reference. The test compounds are run
at two concentrations (5.4 .mu.M and 16 .mu.M) and the apparent
permeability coefficient is reported as P.sub.app in cm/sec and
values reported as mean.+-.standard deviation.
In vitro BBMEC Permeability
[0127]
3 In vitro BBMEC permeability P.sub.app(.times.10.sup.5 cm/sec)
P.sub.app(.times.10.sup.5 cm/sec) Compound at 5.4 .mu.M at 16 .mu.M
Mannitol (standard) 2.76 .+-. 0.23 2.76 .+-. 0.23 Example 1H 4.14
.+-. 0.69 3.44 .+-. 0.86
* * * * *