AP1335A

AP1335A - Method for preparing substituted 4-phenyl-4-cyclohexanoic acids.

Info

Publication number: AP1335A
Application number: APAP/P/2000/001782A
Authority: AP
Inventors: Kevin Webb; Wilford Mendelson; Jian-Hoa Chen
Original assignee: Smithkline Beecham Corp
Priority date: 1997-10-10
Filing date: 1998-10-07
Publication date: 2004-11-29
Also published as: IL135434A; TW440557B; ID25536A; UA67753C2; AU741832B2; TR200000945T2; NO20001777D0; PL339759A1; EA200000406A1; EP1043930A4; BG104302A; BR9814064A; EP1043930A1; PL191974B1; AP2000001782A0; SA99191000A; HUP0003905A2; MA24670A1; PE121599A1; CN1192025C

Abstract

This invention relates to a method of preparing a compound typre where at least one of r' or r'' is a carboxyl group (I) by treating a compound of formula (II) with a Group II(a) metal halide, with an aprotic dipolar amide-based solvent and water.

Description

This invention relates to a method of preparing a compound type where at least one of R' or R is a carboxyl group (1) by treating a compound of formula (II) with a Group 11(a) metal halide, with an aprotic dipolar amide-based solvent and water.

(56) Documents Cited : (JS 5 552 438 A US 6 452 022 A liiventors

MENDELSON Wiiford

592 General Learned Road, King of Prussia,

PA 19406,

UNITED STATES OF AMERICA

CHEN 3ian-Hoa

Egypt Road,

Apt E202,

Audubon, PA 19403,

UNITED STATES OF AMERICA

APV 0 13 5 5

Method for Preparing Substituted 4-PhenyI-4cyanocyclohexanoie Acids

Scope of the Invention

This invention covers intermediates and a synthetic route for making 4-cyano-45 (3-cyclopentyloxy-4-methoxyphenyl)cyclohexanoic acid and its analogs. This acid and its named analogs are selective for inhibiting the catalytic site in the phosphodiesterase isoenzyme denominated IV (PDE IV hereafter) and as such the acids are useful in treating a number of diseases which can be moderated by affecting the PDE IV enzyme and its subtypes.

Area of the Invention

Bronchial asthma is a complex, multifactorial disease characterized by reversible narrowing of the airway and hyper-reactivity of the respirator)’ tract to external stimuli.

Identification of novel therapeutic agents for asthma is made difficult by the fact 15 that multiple mediators are responsible for the development of the disease. Thus, it seems unlikely that eliminating the effects of a single mediator will have a substantial effect on all major components of chronic asthma. An alternative to the mediator approach is to regulate the activity of the cells responsible for the pathophysiology of the disease.

One such way is by elevating levels of cAMP (adenosine cyclic 3’,5 monophosphate). Cyclic AMP has been shown to be a second messenger mediating the biologic responses to a wide range of hormones, neurotransmitters and drugs; [Krebs Endocrinology Proceedings of the 4th International Congress Excerpta Medica, 17-29, 1973], When the appropriate agonist binds to specific cell surface receptors, adenylate cyclase is activated, which converts Mg⁺²-ATP to cAMP at an accelerated rate.

Cyclic AMP modulates the activity of most, if not all, of the cells that contribute to the pathophysiology of extrinsic (allergic) asthma. As such, an elevation of cAMP would produce beneficial effects including: 1) airway smooth muscle relaxation, 2) inhibition of mast cell mediator release, 3) suppression of neutrophil degranulation, 4) inhibition of basophil degranulation, and 5) inhibition of monocyte and macrophage activation. Hence, compounds that activate adenylate cyclase or inhibit phosphodiesterase should be effective in suppressing the inappropriate activation of airway smooth muscle and a wide variety of inflammatory cells. The principal cellular mechanism for the inactivation of cAMP is hydrolysis of the 3’-phosphodiester bond by y y u one or more of a family of isozvmes referred to as cyclic nucleotide pi: re c Woe fPDEse

It has now been shown mat a distinct cyclic nucleotide phosphom e . ip! C wozytne. PDE IV, is responsible for cAMP breakdown in airway smooth ,· ano innamruatory cells. [Torphy, Phosphodiesterase Isozymes: Potential Tai-yets for Novel Anti-asthmatic Agents in New Drugs for Asthma, Barnes, ed. IB< ..-. -icw Services Ltd,. 1989J. Research .indicates that inhibition of this enzyme no, produces airway smooth muscle relaxation, but also suppresses degranulaoon of mast cobs, basophils and neutrophils along with inhibiting the activation of mo' . , o-s and neutrophil··. Moreover, the beneficial effects of PDE IV inhibitors are niui --4potentiated when adenylate cyclase activity of target cells is elevated by appropriate hormones or autocoids, as would be the case in vivo. Thus PDE IV inhibitors, would be , ! . ioe in the asthmatic lung, where levels of prostaglandin E? and pnw;., -, tactivators of adenylate cyclase, are elevated. Such compounds would oiler a unique approach toward the pharmacotherapy of bronchial asthma and possess significant -therapeutic advantages over agents currently on the market.

The process and intermediates of this invention provide a means tor rmfong certain 4-substituted-4-(3,4-disub$titutedphenyl)cyclohexanoic acids whu · setior wealing asthma, and other diseases which can be moderated by affecting the PDE IV enzyme and its subtypes. The final products of particular interest are fully ae scribed in U.S. patent 5,552,483 issues 03 September 1996. The information and representations disclosed therein, in so far as that information and those representations are necessary io the understanding of this invention and its practice, in total, are incorporated herein i:y reference,

Summary of the Invention flirt invention relates a method for making a compound of formula ·

ΑΡ/Γ7 0 0 / 0 1 T 8 2

R. Xv

wherein

Ri is -(L.R4R5)_nC<.Ufo-l y.,R4R5)n)R6> (CR4R5)nC(O)NR4(CR4Rfor>.iR6, * i. ·· -Rs h( R4R5)mR6, ~(CR4R.5)_rR6 wherein the alkyl moieties may re optionally substituted with one or more halogens;

rn is 0 to 2;

n is 1 to 4;

AP li Ο 1 3 3 5 r is 0 to 6;

R.4 and R5 are independently selected from hydrogen or a C] _2 alkyi;

R6 is hydrogen, methyl, hydroxyl, aryl, halo substituted aryl, arvloxyCim alkyl, halo substituted aryloxyCi-3 alkvl, indanyl, indenyl, C7-11 polycycloalkvl, tetrahvdrofuranyl, furanyl, tetrahydropyranyl, pyranyl, tetrahydrothienvl, thienyl, tetrahydrothiopyranyl, thiopyranyl, C3-6 cycloaikyl, or a C4-6 cycloaikyl containing one or two unsaturated bonds, wherein the cycloaikyl and heterocyclic moieties may be optionally substituted by 1 to 3 methyl groups or one ethyl group;

provided that:

a) when R6 is hydroxyl, then m is 2; or

b) when Rg is hydroxyl, then r is 2 to 6; or

c) when R6 is 2-tetrahydropyranyl, 2-tetrahydrothiopyranyl,

2-tetrahydrofuranyl, or 2-tetrahydrothienyl, then m is 1 or 2; or

d) when Rg is 2-tetrahydropyranyl, 2-tetrahydrothiopyranyl,

2-tetrahydrofuranyl, or 2-tetrahydrothienyl, then r is 1 to 6;

j e) when n is 1 and m is 0, then R6 is other than H in

-(CR4R5)nO(CR4R5)mR6;

X is YR?, halogen, nitro, NH₂, or formyl amine;

X2 is 0 or NRg;

Y is O or 5(0)017 m'is 0, 1, or 2;

Ro is independently selected from -CH3 or -CH2CH3 optionally substituted by or more halogens;

R3 is hydrogen, halogen, C1-4 alkyl, CH2NHC(O)C(O)NH2, halo-substituted 25 C1-4 alkyl, -CH=CR8’R8’, cyclopropyl optionally substituted by Rs’. CN, ORs,

CH2OR8, NRsRlO, CH2NR8R10, C^H, C(O)ORs, C(O)NRsRl0, or CCR87 R8 is hydrogen or Cj.4 alkyl optionally substituted by one to three fluorines; Rg’is Rs or fluorine;

RjO is ORs orRn;

Rj 1 is hydrogen, or C1.4 alkyl optionally substituted by one to three fluorines;

Z’ is O, NR9, NORs, NCN, C(-CN)2, CRsCN, CR8NO2, CRsC(O)OR8,

CR8C(O)NR8R8, C(-CN)N02, C(-CN)C(O)ORc>, or C(-CN)C(O)NRsR8;

R’ and R are independently hydrogen or -C(O)OX where X is hydrogen or metal or ammonium cation;

which method comprises:

a) combining a Group 1(a) or Group 11(a) metal halide, with an aprotic dipolar amide-based solvent and water and a compound of formula A or B,

AP/P/ 0 0 ! 0 11 ff 2 . . . a < _e 5,

V t v -

A B where R,, Ry, X? and X are the same as for formula (I);

b) heating the combination to a temperature of at least about * v , .

>·ι -a .,u!y under an men atmosphere;

a 1 precipitating out a compound of formula (I) by adding a si > .e , said combination:

d) removing the anime-based solvent and water from said pre· . :·„ mid mJ!

1) purifying further the precipitate, or 21 acidifying the precipitate to obtain the free acid.

Specific Embodiments of rite Invention

This process involves the synthesis of certain 4-substituted-4-(3,4d;substitutedphenyl)cyclohexanoic acids. It allows for converting a cyanoepoxide to its corresponding homologated acid via the use of a Group 1(a) or 11(b) salt intermediate.

The compounds which arc made by this process are PDE IV inhibited They arc useful for treating a number of diseases as described in U.S. patent 5.552 w38 issued 3 September 1996.

The preferred compounds which can be made by this process are a·. S ms:

Pteierred Rj substitutents for the compounds of all named formulas arc City· r ’ CH2-C5-6 cycloalkyl. C4-6 cycloalkyl unsubstituted or substituted with

OIIC7. i 1 polycycloalkyl, (3- er 4-cyclopentenyl), phenyl, tetrahydrofuran-i-yl. benzyl or C2 alkyl unsubstituted or substituted by 1 or more fluorines, -(Cn2)l-3QO)O(CH2)0-2CH5, -iCH2)l-3O(CH2)0-2CH3, and-(CHz 2 . ·

Preferred X groups for Formula (I) or (II) arc those wherein X is YRy and Y m oxy gen. The preferred Xo group for Formula (I) is that wherein Xfo is ow _ .Pwrerred Ry groups are a Cyy alkyl unsubstituted or substituted by 1 or more halogens. The halogen atoms are preferably fluorine and chlorine, more pre;· .b.y fluorine. More preferred R? groups are those wherein Ro is methyl, or the tiawrsubstituted alkyls, specifically a C:_2 alkyl, such as a -CF3, -CHFo, or -( )^: ‘ 1 moiety, Most preferred are the -CHI⁷2 and -CH3 moieties.

AP/F/ 00/01/82 uΟ 1 3 3 5

Most preferred are those compounds wherein R j is -CH2-cyclopropyl, cyclopentvi, 3-hydroxycyclopentyl, methyl or CF2H; X is YR2; Y is oxygen; X2 is oxygen; and R? is CFoH or methyl; and R3 is CN.

The lithium salt of these compound represent a sub-set of preferred compounds. 5 In particular the lithium salt of 4-cyano-4-(3-cyclopentyloxy-4-methoxyphenyl)-r-lcyclohexanecarboxylic acid, i.e., lithium-4-cyano-4-(3-cvclopentyloxy-4methoxyphenyl)-r-l-cyclohexanecarboxylate represents a preferred embodiment. More particularly, the compound c;'r-lithium-4-cyano-4-(3-cyclopentyloxy-4methoxvphenyl)-r-l-cyclohexanecarboxylate is most preferred.

The carboxylate is made by opening the epoxide with a Group 1(a) or 11(a) metal halide to get the acyl nitrile which hydrolyzes to the acid in the presence of water. A problem in preparing the acid from the acyl nitrile is that when the carboxylate is formed from the acyl nitrile, hydrogen cyanide (HCN) is generated. The challenge is one of removing this HCN in a cost-effective way. A feature of this invention is a means for effecting a more efficient removal of HCN. It has been discovered that if the reaction is run in an aprotic dipolar amide-based solvent containing water, when a strong base is added a cyanide salt forms and remains in solution and the carboxylate salt which forms at the same time precipitates out of solution. This permits one to collect the precipitate and remove the solvent, and by that means remove most or essentially all of the cyanide salt from the alkanoic acid salt precipitate. This avoids having to run an extra purification step, such as oxidizing the HCN.

The Group 1(a) or 11(a) metal halides used in this invention are any of the halides of the alkali metals and the alkali earth metals, i.e., lithium, sodium, potassium, rubidium, cesium or francium; and beryllium, magnesium, calcium, strontium, barium, or radium. The preferred metals are lithium and magnesium. The halides include fluoride, chloride, bromide and iodide. The preferred halide is bromide. Lithium and magnesium halides are preferred. Lithium bromide and magnesium bromide are most preferred. Lithium bromide is particularly preferred.

In regards to the amide-based solvents, they are illustrated by the likes of dimethylformamide (DMF), dimethylacetamide, and N-methyl pyrrolidinone. DMF is most preferred. A second organic solvent can be used in addition to the amide-based solvent. For example acetonitrile has been used successfully in the reaction illustrated

AP/P/ 00/017 8*2 t 7 Η

V *

Μ* «ο below Normally water is added to the reaction pot as it hydrolyzes the ac b. nitrile ir. to give the alkanoic acid Hence a further preferred embodiment of thi -, invention is to use an aprotic dipolar solvent which is water miscible. DMF, dimethHat etamidc. _t.nd N-melbyi pyrrolidinone meet this standard. While it is essentia! to have water in the reaction medium, the amount of water can vary' widely. The reaction goes even when a minor amount of water is present. It is preferred to have at least 0.1 % by we-ght/weight ; wt/wt; present in the reaction vessel, calculated on the basis of both the liquids and ine sudds, ii any, present rn the vessel. A more preferred amount of water i- ,· .: about : 22 wt/wt, and most preferably about 1-5% water by wt/wt. While not ali w suable combinations of water and amide-based solvent systems have been tested, u o known that the reaction will proceed with 20% water (wt/wt). Hence it is believed mat even irgher percentages of water can be used. Optimization of the organic solvew-to-water ; s can be achieved by the skilled practioner. The use of any amount of water in combination with an amide-based solvent is considered to be within the s. . , : this invention.

The reaction can be run at any temperature above about 60 °C. Since, there art numerous combinations of amide-based solvent and water that can be used, c o not practical io set an exact upper limit, to the temperature since that will \a>’ · : - or r-uo'snt selection and the ratio or the selected solvents.

he Group 1(a) or H(ai metal halide opens the epoxide to give an ac; t nitrile. it is hydrolyzed to the acid in the presence of water. But rather than isolate the free acid. rn· insoluble salt of the carboxyiate is formed by adding about 2 or more equivalents of ;; wrong base to the reaction vessel. This base forms two salts, a salt of the vydobexanoic acid and a salt of HCN which is released in the hydrolysis of the acyl nitrile group. The metal cyanide it turns out is soluble in the solvent and the oak of tiie alkanoic acid precipitates out of solution. This makes it possible to separate ov. alkanoic acid salt from the cyanide salt by simply removing the solvent. The invention car. be practiced using less than 2 equivalents of base, but that would possir . vilt in loss of the alkanoic acid because n would not precipitate out of solution, undesirable from an economic standpoint. And unreacted HCN could contaminate the alkanoic acid that did precipitate out or solution. Hence the preferred practice is to usr 2 or more equivalents of the base.

A strong base for the purposes of this invention is any base that will form a salt with the cyanide ion. One can use any base strong enough to form these salts;

formation of the cyanide salt is the more critical of the two criteria for determining if a particular base is useful in this step. Inorganic hydroxides are preferred. For example one can use LiOH, NaOH, or KOH. One can also use ammonium salts, for example tetra-alkylammonium hydroxides or NH4OH. Lithium hydroxide is preferred because the lithium cyanide salt is highly soluble in the aqueous aprotic dipolar amide-based solvent, and thus effects more efficient and more complete removal of the cyanide ion from the acid salt when the amide-based solvent is removed. Lithium cyanide is more soluble in DMF than is sodium cyanide or potassium cyanide. So it is more advantageous to make lithium the cation in the strong base in the salt-forming step of the process.

A perferred practice of this invention is one in which the solvent(s) are charged to the reaction vessel, lithium bromide is added, and then the epoxide. Once the reaction has gone to completion essentially, two or more equivalents of an aqueous solution of lithium hydroxide are added, the cyclohexanoic acid salt is precipitated out of solution and filtered out, and the solvent discarded. The lithium salt of the cyclohexanoic acid can be further purified if needs be to remove residual contaminants such as cyanide salts, or converted to the acid by dissolving or suspending the salt in a solvent and acidifying that material to obtain the free acid.

A representative schematic of the process is set out in Scheme I and Scheme II.

These graphical representations use specific examples to illustrate the general methodology used in this invention.

AP/r/ 0 0'01? 82

Scheme I

MeO

OH

H tsovanillin

Stage 1

Cl

O

MeO

Stage 2

DMF

2) Activated Carbon

H

1) NaBH₄

DMF/MeOH 2) HOAc/Hp

ΗΓ w Μ 1 4 U 5

Met J

Stage 3

1) Cone. HCI Toluene

2) NaHCO, OH

O

Stage 4

1)NaCN Q

DMF MeO A.

2j Toluene/H-,0

Stage 5 υ X^CO₂CH₃CH₃CN, BnMe,N⁺OR H₂O/CH₃OH

2) Crystallize from Methyicyclohexane

O'

MeO.

Stage 6

NaOMe

Dioxane/MeOH

..COXK

MeO .0

SfCOjCHj

NC'i

CN

Stage 7

CO₂CH₃

i) NaHCO₃, NaOMe,

H₂0 Dioxane MeO

2! Cone. HCI

3) Crystallize from Methyicyclohexane/ Ethyl acetate

4) Recrystaliize from xylenes (optional) '1

ON

Stage 8 n CICHjCN MeO

THF/aa. KOH

C₆H_sCH₂N(C₂H₅)₃CI 21 Crystallize from

THF/methylcyclohexane 3) Wash crystals with MeOH

Stage 9

1) LiBr/H₂O DMF/CH₃CN

2) aq. LiOH

3) Wash crystals with EtOAc

AP/*/ 0 0 / 0 1 f 8 2

ΑΡ»Ο 133 5

Ο

CN

Stage 10

1) Ethyl acetate aq. HCI

2) Crystallize from

Ethyl acetate/Hexanes

MeO.

CO₂H

CN

Scheme II illustrates a second very similar set of conditions that can be used in this invention. This scheme follows the same route as the one outlined in Scheme I; some of the conditions in certain steps are changed.

Scheme II

MeO

H

Isovanillin

OH

Stage 2

1) NaBH₄ MeO DMF/MeOH

2) HOAc/H₂O

Stage 3

1) Cone. HCI Toluene

2) NaHCO₃

MeO

Stage 4

Phase-transfer, conditions

MeO

Stage 5

1) %CO₂CH₃

CHjCN, BnMe₃N*OH· H₂O/CH₃OH

2) Cyclohexane/toluene

Stage 7

1) NaOMe, NaHCO_gζΧ Dioxane

CO₂CH₃ 2) Cone. HCI

3) Cyclohexane/toluene

4) Recrystallize from xylenes (optional)

AP/P/ 0 0 / 0 1192

Stage 8

1) CICH₂CN MeO

THF/aq. KOH C₆H₅CH₂N(C₂H₅)₃CI

2) Crystallize from THF/methylcyclohexane

3) Wash crystals with MeOH

ArO 01335

Stage 6 i LiBvH₂O _MeO 9 DMF/CH_;CN T

2) aq, LiOH Ά-,

3) Wash crystals with EtOAc

CN

Stage 10

..............._MeG

1) Ethyl acetate

CO Li ^aq' ^HCI

2) Crystallize from

Ethyl acetate/Heptanes

r.-.......2j COjH

CN

The chemistries illustrated in Scheme I are set out in a co-pending U.S.

application which has been assigned USSN 60/061613 (filed 12 February ί 9°7) and aiso filed as PCT application serial number PCT/US98/02749 designating inter alia the

U.S.; it has been published as WO98/34584. That application is incorporated herein by reference, particularly as regards the chemistries underpinning steps 1-7.

ί The chemistries in Scheme II are set out in PCT application number • 10 PCI7EP98/05504 filed 26 August 1998 which, inter alia, designates the U.S as a selected State. The full disclosure of that application is incorporated herein c v ; reference Sn addition the details, of this second set of chemistries are giver, below.

. A general description of the chemistries in Schemes I and II follows, i A mixture of cyclopentyl chloride, isovanillin and potassium carbonate in j 15 dimethylformamide is stirred at about 125 °C until formation of the cvclopeni vioxy product is deemed to be complete (approximately 2 hours). The mixture is mm2 to 20-25°C, the solid (potassium chloride and potassium bicarbonate) is removed by

I centrifugation and is washed with methanol before being discarded, The dimethylformamide liquors and methanol wash are combined for use in the next step, ; 20 The solution of the cyciopentyloxy compound in dimethylformamide and methanol is cooled to about 0‘C and treated with sodium borohydride (approximately ; 1 5 hours). The. temperature is maintained below 5°C. After that the mixture ti stirred • at 0 to 10°C for 30 minutes and at 25-30°C until the reduction reaction is deemed to be complete (approximately 1 hour). Acetic acid 50% is added to destroy the excess : 25 borohydride and the dimethylformamide and methanol are removed by distillation in 5 vacuo. After cooling to 20-25’C the mixture is partitioned between water anc toluene, , The toluene phase, containing the alcohol is washed with demineralised water, passed tntough a filter for use in the next step.

Tlie, solution of alcohol in toluene is treated with concentrated hydrochloric acid • 30 (min 36% S at 15 to 25°C. The organic phase, containing the chloro compound is separated and treated with sodium bicarbonate to neutralize the HCI traces. ’ ik solid (sodium chloride, sodium bicarbonate) is removed by filtration.

I 10

APOf 33 5

The solution of the chloro compound is concentrated by distillation in vacuo. After cooling to about 20°C, demineralised water, tetrabutylammonium bromide and sodium cyanide are added. After that the mixture is heated to 80°C and stirred at this temperature until the cyanidation reaction is deemed to be complete (approximately 2 hours).

After cooling to <60°C the mixture is partitioned between water and toluene. The toluene phase, containing the cyano compound is washed at 30 to 25°C with demineralised water, distilled in vacuo to minimum volume and to this is added acetonitrile. The product solution in acetonitrile is used directly in the next step.

Solutions of methyl acrylate in acetonitrile and Triton B and acetonitrile are prepared. About 16.6% of the methyl acrylate solution is added to the cyano compound solution at <25°C. About 12.5% of the Triton B solution is the added, the mixture is stined for some minutes and then cooled back to <25°C. This addition sequence is repeated three more times, then the final 33% of the methyl acrylate solution and the final 50% of the Triton B solution are added in two portions. The reaction mixture is stirred at 20 to 25°C until the reaction is deemed to be complete (approximately 2-3 hours). The acetonitrile is removed by vacuum distillation to minimum volume. The mixture is partitioned between cyclohexane/toluene and water at 50°C. The cyclohexane/toluene phases, containing the pimelate is aged for about 1 hour at about 0 °C.

The product is isolated by centrifugation and washed with cold (<0°C) cyclohexane/toluene. The wet cake vacuum dried at max 50°C to give the pimelate as an off white to beige powder.

A 29% methanolic solution of sodium methoxide is added in one lot to a 25 solution of the pimelate in dioxane. The mixture is heated to about 75°C (reflux) and maintained at this temperature until formation of the 2-carbomethoxycyclohexan-1 -one is deemed complete (approximately 1 hour). Much of the methanol is distilled out and replaced with dioxane. Sodium bicarbonate and deminieralised water are added to the . the mixture is heated to reflux (about 85 to 88°C) and maintained at this temperature until formation of the cyclohexan-l-one is deemed to be complete (approximately 10 hours).

After that the mixture is cooled to <60°C and concentrated hydrochloric acid solution is added to reduce the pH from >10 to 7.5

Much of the dioxane and methanol is removed by distillation in vacuo. After 35 that the mixture is partitioned between cyclohexane/toluene and water at about 70°C.

The organic phase, containing the ketone is washed twice with demineralised water at about 70°C.

ΑΡ/Γ7 00/01/82

APOO13>⁵

The product solution >s cooled to 10°C and aged for about I hour at 7 to i 1~C. The product is isolated by filtration and washed with cold (I0°C) cyclohexane/toiuene. the we! cake is vacuum dried at max 50°C to give the ketone as an off whit;: powder

The dicarbonitrile is prepared from the ketone by treating the ketone with 5 ehioroacetonitriie in the presence of an inorganic base and a catalytic amount of benzykriethviammonium chloride (BTEAC). The ketone and a slight excess ojf ehioroacetonitriie in a suitable solvent such as THF is charged into a mixture of strong base (aqueous potassium hydroxide) and BTEAC and a water miscible solvent such as tetrahydrofuran at reduced temperature, about 0° C or thereabouts. The reaction is maintained at about that temperature for the duration of the reaction, usually about 1 hour The product can be isolated or used as a crude oil.

The dicarbonitrile is converted to the cyclohexanecarboxylic acid using a Group l-po or Π(a) metal halide. This reaction is carried out by charging a vessel with ' solvents; in this instance exemplified by DMF, acetonitrile and water, and die Group ‘ 15 La) or Ilia) metal halide (preferably about 1.5 equivalents), LiBr is illustrated : sweeping the vessel with an inert gas; adding the dicarbonitrile A or B, or a mixture of

A and B; and heating the vessel and its contents to about 100° C for a number o; hours, s hours being an example. The reaction is diluted with DMF and optionally v. ater.

i LiOH dissolved in water is added (about a 50% molar excess is preferred).

; 20 suspension is formed. This is stirred at a slightly elevated temperature(40 to SO ^rC) for about an hour or so. The lithium salt is recovered by conventional means.

The acid is prepared, for example, by suspending the lithium salt in an organic . solvent of the likes of ethyl acetate, and treating the suspension with aqueous mineral i acid. The organic solvent is then recovered, washed, and concentrated. The product is 1 25 -Isolated by conventional means.

The following examples are provided to illustrate specific embodiments of the invention, not to limit it. What is reserved to the inventors is set forth in the claims appended hereto.

Specific Examples

- 30 Example 1

Preparation of 5-eycIopentvloxv-4-methoxybenzaldehvde ! A mixture of cyclopentyi chloride (8.48 g, 0.08 moles), isovanillin (6 (2 g, 0.04 moles) and potassium carbonate (LI g, 0.08 moles) in dimethylformamide (4 04 g) was ί stirred in the reactor (100 mL) at 120 to 125 °C for 1.5 hours. A sample was taken to

135 verify the batch conversion. Result (GC): 0.5 area % isovanillin (target: < 1 .·) area %).

> The mixture was cooled to 20 C and filtered to remove the solid (potassium bicarbonate, potassium chloride). The wet cake was washed with methanol.

Z .8 I t o i 0 0

Example 2

Preparation of 3-cyclopentvloxy-4-methoxvbenzvI alcohol The dimethylformamide liquors and methanol wash from Example 1 were combined and retransferred into the cleaned reactor. An additional amount of methanol 5 (8.52 g) was added and the batch was cooled to 0°C. Sodium borohydride (0.49 g,

0.0129 moles) was added in small portions over 1 hour and 10 minutes maintaining the temperature between 4 and 9 °C. The batch was stirred at 7.2 to 10 °C for 30 minutes and then heated to 25 °C. A sample was taken after 110 minutes stirring at 25 to 31 °C and analysed (GC) and the reaction was deemed to be complete. Acetic acid 50% (1.80

g) was charged to the reactor to quench any remaining sodium borohydride. The batch temperature of 24 to 25 °C was maintained during this charge. The dimethylformamide and methanol were removed by distillation in vacuo (end of distillation: 58 °C, 6 mbar). After cooling to 20 - 25 °C the mixture was partitioned between water (3.13 g) and toluene (28.07 g). The toluene phase (containing the captioned compound) was washed with demineralised water (2.65 g).

Example 3

Preparation of 4-Chloromethyl-2-cyclopentyloxv-l-methoxvbenzene

The toluene solution from Example 2 was cooled to 20 °C and concentrated hydrochloric acid (37.5%; 9.80 g) was added keeping the temperature between 20 and

22.7 °C. A sample was taken 40 minutes after the addition was complete and analysed (GC) and the reaction was deemed to be complete. The phases were allowed to separate and the lower, aqueous phase discarded. Sodium bicarbonate (1.20 g) was charged to the reactor to neutralize the remaining hydrochloric acid. After stirring for 15 minutes the mixture was cooled to 23 °C and filtered to remove the solid (sodium bicarbonate, sodium chloride). A part of the toluene (17.07 g) was removed by distillation in vacuo (end of distillation: 28 °C, 7 mbar).

Example 4

Preparation of 4-Cyanomethvl-2-cycIopentyloxy-l-methoxvbenzene

After cooling the solution from Example 3 to < 25 °C tetra-butylammonium bromide (0.205 g, 0.63 mmoles), demineralised water (2.775 g) and sodium cyanide (1.976 g, 0.039 moles) were added, the mixture was heated to 80 °C and then stirred at 78.1 to 80.4 °C for 1 hour and 50 minutes. A sample was taken to verify the batch conversion.

Toluene (5.841 g) and demineralised water (8.76 g) were added, the phases were allowed to separate (at about 54 °C) and the lower, aqueous phase discarded. The toluene phase (containing the product) was washed with demineralised water (13.32 g). The toluene was removed by distillation in vacuo (end of distillation: 55 °C, 1 mbar).

AP/P/ 0 o / 0 1 7 8' 2 fiji ο ί 1 $'> 3

Example 5

Preparation of Dimethvl-4· cvano-4-(3-cvclopentyloxv-4-methoxv-phen vi .pimelate

The cy anomethyl compound prepared in Example 4 (9.05 g at 85.4%. 7 73 g at ’00%; 0.0334 moles.) was charged in the reactor (0.5 L) at room temperature Acetonitrile (28.56 g) and demineralised water (0.07 g) was charged to the reactor. Solutions of methyl acrylate (6.88 g,0.029 moles) in acetonitrile (4.02 g) and methanolic Triton B (40.2% 0.94 g, 2.269 mmoles Triton B) in acetonitrile Ak06 g) were prepared. A first portion, about 16.6% of the methyl acrylate solution ; 1 81 g> was added at 20 'C. A first portion, about 12.5% of the Triton B solution (0.6? kg) was then added. The batch temperature after the addition was 31 °C. A second portion, about 16.6% of the methyl acrylate solution (1.82 g) was added at 28 °C. A second portion, about 12.5% of the Triton B solution (0.63 g) was then added. The batch temperature after the addition was 36 °C. A third portion, about 16.6% of the methyl acrylate solution (1.81 g) was added at 35 °C. A third portion, about 12.5%- of the Triton B solution (0.62 g) was then added. The batch temperature after the addition was 32 °C. A fourth portion, about 16.6% of the methyl acrylate solution (1.81 gj was added at 32 °C. A fourth portion, about 12.5% of the Triton B solution (0.6? g) was then added. The batch temperature after the addition was 36 °C. A fifth portion, about 33.2% of the methyl acrylate solution (3.64 g) was added at 34 °C. A fifth portion, about 25%> of the Triton B solution (1.25 g) was then added. The batch temperature after the addition was 38 °C. The last portion, about 25% of the Triton B solution (i.25 g) was then added. The batch temperature after the addition was 36 °C. The reaction mixture was stirred for 1.5 hours at 20 - 25 °C. The acetonitrile was removed by distillation in vacuo (end of distillation: 59 °C, 20 mbar). The mixture was partitioned at about 50 °C between cyclohexane/toluene (1145.9/254.6 g) and water (559.8 gi. The cyclohexane/toluene phase (containing the product was washed with demineralised water (559.8 g) at 50 to 52 °C. To crystallize the captioned product, the batch was cooled over 50 minutes to 0 °C. The batch was then seeded with pimelate and aged for 1 hour at -1 to 1 °C. The pimelate was filtered and washed with cyclohexanc/foluene (6.51 g/1.44 g) and recovered by conventional means.

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Example 6

Preparation of 4-Cvano-4-(3-cvclopenty]oxv-4-methoxvphenvl)cyclohexan-l-one

The pimelate made in Example 5 (76.52g, 1,8112 moles) was charged into the reactor (100 mL). Dioxane (2214g) and a 29.1% methanolic of sodium methoxide (0.44g, 24 mmoles) were added. The mixture was heated to reflux (77 °C) and stirred at this temperature for 1 hour. A sample was taken to verify the batch conversion. The methanol was removed by distillation (16.82g distillate) to a bottom temperature of 97 °C. the loss of dioxane during this distillation was compensated by adding of fresh dioxane (121 -6g). Sodium bicarbonate (22.2g, 26. mmoles) and demineralised water (2.47g) were added. The mixture was heated to reflux (87 °C) and stirred at about to 87 °C for 10 hours. A sample was taken to verify the batch conversion. The content of the reactor was cooled to 78 °C. Dioxane (0.13g) and demineralised water (0.12g) were added to simulate a flush. After cooling to <60 °C concentrated hydrochloric acid (37%, 0.265g) was added to adjust the pH to 7.5. The dioxane, methanol and a part of water (27.73g distilled) were removed by vacuum distillation (end of distillation: 66 °C, 305 mbar).

Under stirring, cyclohexane (180.0g) and toluene (65.5g) were charged to the reactor. The mixture was heated to 70 °C and the phases were allowed to separate at 70 °C and the lower, aqueous phase was discarded. The organic phase, containing the captioned ketone was washed in two portions with demineralised water (169.4g total) at about 70 °C. Cyclohexane (165.Og) was added to the reactor to simulate a flush. To crystallize the product, the batch was cooled to 10°C over 1 hour. Then it was aged for 6 hours at 9 to 11 °C to complete the crystallization. The product batch was filtered and washed with cyclohexane/toluene (81.5g/27.2g).

Example 7

Preparation of cri-6-F3-(cvclopentyloxy')-4-methoxvphenvl')1-l-oxaspiroi2.51octane2,6-dicarbonitrile.

A 500mL round bottom flask equipped with an overhead stirrer, internal thermometer, and a nitrogen inlet was flushed with nitrogen. The flask was charged with 50% potassium hydroxide in water (22.0 g) and tetrahydrofuran (55.0 mL). While stirring at room temperature, benzyltriethylammonium chloride (0.81 g, 35 mmol, 0.05 equivalent) was added. The solution was cooled to 0 °C. To a pressure-equalizing addition funnel was charged a solution containing tetrahydrofuran (55.0 mL), 4-cyano4-(3-cyclopentyloxy-4-methoxyphenyl) cyclohexan-l-one (23.0 g, 73 mmol, 1.0 equivalent), and chloroacetonitrile (5.9 g, 78 mmol, 1.07 equivalent) at room temperature. While stirring the flasks contents at 0 °C, the solution in the pressure addition funnel was added over 15 minutes. The temperature was maintained between 0 and 5 °C, and stirred for one hour. The reaction was warmed to 25 °C, diluted with

AP/P/ 00/01/82

Ak.r' v Ο 1 3 3 ~·

Winer (90.0 mL), and ethyl acetate (90.0 mL). The solution was stirred and allowed to settle for 30 minutes. The layers were separated, the organic layer was isolated, and concentrated by vacuum distillation to a residue. Methylcyciohexane/THF (5:1) (54.0 mL) was added and the solution was heated to 60 °C then cooled to 20 ° C over 90 minutes; the product began to crystallize at about 40 °C. The suspension was then cooled to 0 ^C C and held at -0 to 5 °C for two hours. The product was filtered and washed with a methanol mixture (46.0 mL) at 0 °C. The product was dried to afford the captioned product as a white crystalline solid.

Example 8

Preparation of cfi-Lithium-4-evano-4-(3-cvclopentvloxv-4-methoxvphenvS t-r-i cyclohexanecarboxylate, 2.

To a 1.0 L, 3-neck round bottom flask equipped with an overhead stirrer, internal thermometer and a reflux condenser connect to a caustic scrubber was charged dlmethylformamide (200 mL). acetonitrile (200 mL), lithium bromide (32.4 g, ().37 moi) and water (5.6 g, 0.31 mol). The suspension was stirred until a solution was evident, followed by the addition of cw-6-[3-(cyclopentyloxy)-4-methoxvphenyi)]-loxaspiro[2.5]octane-2,6-dicarbonitrile,l, (90.0 g, 0.25 mol). The contents of she flask > 20 were heated between 90 and 95 °C for 8 to 12 hours. The reaction was cooled to 60 C i and diluted with dimethylformanude (270 mL). To the amber solution (60 °C) was quickly added an aqueous solution of lithium hydroxide (21.65 g, 0.51 mol of lithium hydroxide monohydrate dissolved in 112.5 mL of water). The suspension was stirred at 60 °C for 1 hour, cooled to 5 ^CC, and held at 5 °C for 1 hour. The suspension was ' 25 filtered, washed with ethyl acetate (100 mL) and air dried to provide 2 in 79.5 % corr Ϊ yield.

ί i

APO ί J 3 5

Example 9

Preparation of c/5-4-cvano-4-f3-cvclopentyloxv-4-methoxyphenyl)-r-1cyclohexanecarboxylate. 3, a

CN

1) Ethyl acetate 3N aq. HCI h,C

Cl

CCILi ²) Crystallize from

Ethyl acetate/Heptane

CC^H

CN

To a 1.0 L, 3-neck round bottom flask equipped with an overhead stirrer and an internal thermometer was added cis-lithium-4-cyano-4-(3-cyclopentyloxy-4methoxyphenyl)-r-l-cyclohexanecarboxylate, 2 (58.5 g, 0.167 mol) and ethyl acetate (500 mL). The light suspension was stirred at ambient temperature followed by the addition of 3N aqueous HCI (70 mL, 0.21 mol). The reaction was stirred for ten minutes and transferred to a separatory funnel. The organic layer was isolated and washed once with water (100 mL). The organic layer was isolated and filtered into a clean 1.0 L, 3-neck round bottom flask equipped with a distillation head and an overhead stirrer. The reaction was concentrated by distilling off ethyl acetate (200 mL).

The contents of the flask were cooled to 60 °C followed by the addition of heptane (275 mL). The suspension was cooled to 5 °C, held at 5 °C for 2 hours, filtered, and washed with cold (5 °C) heptane (50 mL). The product was dried in a vacuum oven to constant weight to afford 50.0 g (85%) of 3.

Claims

What is claimed is;

S A method tor making a compound of formula 1

A] is -(CR4R5)nC(O,iO(v;R4R5)inR6> *(CR4R5)nC(O)NR4(CR4K5/mR6. (CR4R5)_nO(CR4R5)mR6, ^or -(CTMRsPrRg wherein the alkyl moieties may b: optionally substituted with one or more halogens;

m is 0 to 2; n is 1 to 4; r is 0 to 6;

PU and Rs are independently selected from hydrogen or a C 3.? alkyl

Ry is hydrogen, methyl, hydroxyl, aryl, halo substituted aryl, arylo.x - .3 alkyl hato substituted aryloxyCi-3 alkyl, indanyl, indenyl, C741 polycvcloalkyl, tetrahydrofuranyl, furanyl, tetrahydropyranyl, pyranyl, tetrahydrothienyl, thieryL tetrahvdrothiopyranyl, thiopyranyk C3-6 cycioaikyl, or a C4-6 cycioaikyl containing one cr two unsaturated bonds, wherein the cycioaikyl and heterocyclic moieties may be optionally substituted by 1 to 3 methyl groups or one ethyl group;

provided that;

a'· when Rg is hydroxyl, then m is 2; or b 1 when Rg is hydroxyl, then r is 2 to 6; or

c) when Rg is 2-tetrabvdropyranyl, 2-tetrahydrothiopyranyl.

2-tetrahydrofuranyl, or 2-tetrahydrothienyi, then m is 1 or 2; or di when Rg is 2-tetrahydropyranyl, 2-tetrahydrothiopyranyi,

2-tecrahydrofuranyI, or 2-tetrahydrothienyl, then r is 1 to 6; e ί when nisi and m is 0, then Rg is other than H in

-(CR4R5)nO(CR4R5)mR6;

X is YRc, halogen, nitro, NIL, or formyl amine;

X;> is O or NRg;

¥ is O or S(O)nf; in'is 0, 1, or 2;

Ry is independently selected from -CH3 or -CH2CH3 optionally substituted by 1 or more halogens;

Rr is hydrogen, halogen, C3-4 alkyl, CH2NHC(O)C(O)NH2, halo-substituted C1 -4 alky... -CHsCRg’Rg’, cyclopropyl optionally substituted by Rgt CN. ORy CHyORg, NRgRw, CH2NR8R10. CCZhH, C(O)ORs, C(0)NRgRio, or CsCR.y

AP/P/ 0 0 / 0 1 ? 8 2 υ 0' ί 3 3 5

Rg is hydrogen or C 1.4 alkyl optionally substituted by one to three fluorines; Rg-is Rg or fluorine;

RlO is ORs orRji;

Rl 1 is hydrogen, or Cj_4 alkyl optionally substituted by one to three fluorines; 5 Z’ is O, NRp, NOR8, NCN, C(-CN)2, CRsCN, CRsNO?. CRsC(O)OR8.

CR8C(O)NR8R8. C(-CN)NO2, C(-CN)C(O)OR9, or C(-CN)C(OiNRsR8;

R’ and R are independently hydrogen or -C(O)OX where X is hydrogen or metal or ammonium cation;

which method comprises;

10 a) combining a Group 1(a) or Group 11(a) metal halide, with an aprotic dipolar amide-based solvent and water and a compound of formula 11(a) or 11(b),

CN where R,, R3, X2 and X are the same as for formula (I)

b) heating the combination to a temperature of at least about 60° for several hours, optionally under an inert atmosphere;

c) precipitating out a compound of formula (I) by adding a strong base to said combination;

d) optionally removing the amide-based solvent and water from said precipitate, and

1) purifying further the precipitate, or
2) acidifying the precipitate to obtain the free acid.

2. The process of claim 1 wherein the product is a compound wherein R1 is -CH2-cyclopropyl, cyclopentyl, 3-hydroxycyclopentyl, methyl or CF2H; X is YR2; Y is oxygen; X2 is oxygen; and R2 is CF2H or methyl; and R3 is CN.

' 3. The process of claim 1 or 2 wherein the Group 1(a) or 11(a) metal halide is lithium or magnesium halide.

4. The process of any one of claims 1-3 wherein the Group 1(a) or 11(a) metal halide is lithium bromide or magnesium bromide.

5. The process of any one of claims 1-4 in which the aprotic dipolar amidebased solvent is dimethylformamide, dimethylacetamide, or N-methyl pvrrolidinone.

6. The process of any one of claims 1-5 wherein the Group 1(a) or 11(a) metal halide is lithium bromide and the amide-based solvent is dimethylformamide.

AP/P/00'0 1 ?82 y v i 3 o *' ' . The process of any one of claim 1-6 wherein water is present in an 'amount greater than 0.1 % hv weight/weight of the contents of the reaction ve ssel.

S The process of any one of claims 1-7 in which the strong base is lithium ” hvdroxide.

5 9. The process oi any one of claim 1-8 wherein the compound ot formula iliai or iisb) is cis-6-[3-(cyclopentyloxy)-4-methoxyphenyl)]-l-oxaspiro[2.5]octane2,6-dicarbonitriie.

.10, A product of the process of any one of claims 1-9 which is css- hthium-4· cyano-4-(3-cyclopentyloxy-4-methoxyphenyl)-r-l-cyclohexanecarboxyiate.

10 11. A compound which is cti-lithium-4-cyano-4-(3-cyclopentyioxy~imethoxy phenyi )-r-1 -cyclohexanecarboxylate.

12 A compositon or matter comprising essentially pure cn-lithiuni-d -cyano4~(?-eyeiopernyioxy-4-methoxyphenyl)-r-l-cyclohexanecarboxylate.