GB2128991A

GB2128991A - Heterocyclic containing cyclobutyl amines

Info

Publication number: GB2128991A
Application number: GB08325826A
Authority: GB
Inventors: Bernard John Armitage; John Rosindale Housley; James Edward Jeffery
Original assignee: Boots Co PLC
Current assignee: Boots Co PLC
Priority date: 1982-09-30
Filing date: 1983-09-27
Publication date: 1984-05-10
Also published as: ZA836849B; EP0108488B1; DE3362328D1; BG38638A3; RO87259A; KR900005256B1; FI79529B; IE56001B1; PT77364B; NO833528L; DD218094A5; JPS5989659A; FI833453A0; PL243950A1; CS713183A2; ES526089A0; YU196483A; IL69734A; EP0108488A1; DK435583A

Abstract

Compounds of formula I <IMAGE> I in which R1 is a heterocyclic ring containing one or more heteroatoms selected from N, O and S; in which R2 is H, a straight or branched chain alkyl group containing 1 to 4 carbon atoms, an alkenyl group containing 3 to 6 carbon atoms, an alkynyl group containing 3 to 6 carbon atoms or a cycloalkyl group containing 3 to 7 carbon atoms; in which R3, is H, a straight chain alkyl group containing 1 to 3 carbon atoms or a formyl group in which R4, R5 and R6 which may be the same or different, are H, halo, trifluoromethyl, hydroxy, an alkyl group containing 1 to 3 carbon atoms, an alkoxy group containing 1 to 3 carbon atoms, phenyl or R4 and R5, together with the carbon atoms to which they are attached, form an optionally substituted second benzene ring; and their pharmaceutically acceptable salts have utility in the treatment of depression. Pharmaceutical compositions and processes for the preparation of compounds of formula I are disclosed.

Description

1

SPECIFICATION

Therapeutic agents GB 2 128 991 A 1 This invention relates to compounds having useful therapeutic activity particularly but not exclusively as 5 antidepressants, to pharmaceutical compositions containing such compounds and to processes for the preparation of such compounds.

The present invention provides compounds of formula 1 R,$ CHRIM2R 3 10 5' IRS --h 1 15 in which R, is a heterocyclic ring containing one or more heteroatoms selected from N, 0 and S; in which R2 is H, a straight or branched chain alkyl group containing 1 to 4 carbon atoms, an alkenyl group containing 3 to 6 carbon atoms, an alkynyl group containing 3 to 6 carbon atoms or a cycloalkyl group containing 3to 7 carbon atoms; in which R3, is H, a straight chain alkyl group containing 1 to 3 carbon atoms or a formyl group in which R4, R5 and R6 which may be the same or different, are H, halo, trifluoromethyl, hydroxy, an alkyl group containing I to 3 carbon atoms, an alkoxy group containing 1 to 3 carbon atoms, an alkylthio group containing 1 to 3 carbon atoms, phenyl or R4 and R5, together with the carbon atoms to which they are attached, from an optionally substituted second benzene ring; and their pharmaceutically acceptable salts.

R, is a heterocyclic ring which may contain 5 or 6 atoms and may contain one heteroatom (for example furyl, thienyl, pyrrolyl, pyridyl, tetrahydrofuryl or tetra hyd rothienyl) or more than one heteroatom which may be the same (for example imiclazolyl, pyrazolyl, pyrazinyl, pyrimiclinyl, pyriclazinyl, triazolyl, tetrazolyl or clithianyl) or different (for example thiazolyl). The heterocyclic ring maybe substituted for example by one or 30 more alkyl groups containing 1 to 3 carbon atoms (for example methyl), halo (for example fluoro or chloro) hydroxy, alkoxy groups containing 1 to 3 carbon atoms (for example methoxy) or trifluoromethyl. In preferred compounds of formula 1, R, is a furyl, thienyl, pyridyl, tetra hyd rofu ryl, dithianyl, methylfuryl, methylpyrrolyl, methylimidazolyl, methylpyrazolyl, methyltetrazolyl or methylthiazolyl group. 35 When R2 is an alkyl group, the alkyl group maybe branched and contains 1 to 4 carbon atoms (for example 35 methyl, ethyl or isopropyl). When R2 is an alkenyl or an alkynyl group, the group contains 3 to 6 carbon atoms (for example allyl or propynyl). When R2 is a cycloalkyl group, the cycloalkyl ring contains 3 to 7 carbon atoms (for example cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl). When R3 is an alkyl group, the group contains 1 to 3 carbon atoms (for example methyl, ethyl, propyl or isopropyl). In preferred compounds of formula 1, R2 is H or methyl and R3 is H, methyl or formyl. When R4, R5 or R6 is a halo group, the halo group may be fluoro, chloro, bromo or iodo. When R4, R5 or R6 is an alkyl, alkoxy or alkylthio group, the group contains 1 to 3 carbon atoms (for example methyl, methoxy or methylthio). When R4 and R5 together with the carbon atoms to which they are attached form a second benzene ring, the second benzene ring may optionally be substituted by halo (for example fluoro, chloro or bromo) or by an alkyl group or an alkoxy group containing 1 to 3 carbon atoms (for example methyl or methoxy) or the substituents on the second benzene ring may together with the carbon atoms to which they are attached form a further benzene ring. In preferred compounds of formula I R4 is a halo group (preferably a chloro, bromo or iodo group) or a methyl group, a methylthio group or a phenyl group and R5 is H, a halo group (preferably a chloro group) or R4 and REj together with the carbon atoms to which they are attached forma benzene ring.

Compounds of formula I may exist as salts which pharmaceutically acceptable acids. Examples of such salts include hydrochlorides, maleates, acetates, citrates, furnarates, tartrates, succinates and salts with clicarboxylic amino acids such as aspartic and glutamic acids. Salts of compounds of formula I may exist in the form of solvates (for example hydrates).

Compounds of formula I contain one or more chiral centres. Compounds having one chiral centre exist in 55 two enantiomeric forms and the present invention includes both enantiomeric forms and mixtures thereof.

Compounds having two or more chiral centres exist in diastereo isomeric forms and the present invention includes each of these diastereoisomeric forms and mixtures thereof.

The present invention also includes pharmaceutical compositions containing a therapeutically effective amount of a compound of formula I together with a pharmaceutically acceptable diluent or carrier. 60 In therapeutic use, the active compound may be administered orally, rectally, parenterally or topically, preferably orally. Thus the therapeutic compositions of the present invention may take the form of any of the known pharmaceutical compositions for oral, rectal, parenteral or topical administration. Pharmaceutically acceptable carriers suitable for use in such compositions are well known in the art of pharmacy. The compositions of the invention may contain 0.1 - 90% by weight of active compound. The compositions of the 65 2 GB 2 128 991 A 2 invention are generally prepared in unit dosage form.

Compositions for oral administration are the preferred compositions of the invention and these are the known pharmaceutical forms for such administration, for example tablets, capsules, syrups and aqueous or oily suspensions. The excipients used in the preparation of these compositions are the excipients known in the pharmacists' art. Tablets may be prepared by mixing the active compound with an inert diluent such as 5 calcium phosphate in the presence of disintegrating agents, for example maize starch, and lubricating agents, for example magnesium stearate, and tableting the mixture by known methods. The tablets may be formulated in a manner known to those skilled in the art so as to give a sustained release of the compounds of the present invention. Such tablets may, if desired, be provided with enteric coatings by known methods, for example by the use of cellulose acetate phthalate. Similarly, capsules, for example hard or soft gelatin capsules, containing the active compound with or without added excipients, may be prepared by conventional means and, if desired, provided with enteric coatings in a known manner. The active material in the capsules may be formulated in a sustained release form. The tablets and capsules may conveniently each contain 1 to 500 mg of the active compound. Other compositions for oral administration include, for example, aqueous suspensions containing the active compound in an aqueous medium in the presence of a non-toxic suspending agent such as sodium carboxymethy1cellulose, and oily suspensions containing a compound of the present invention in a suitable vegetable oil, for example arachis oil.

Compositions of the invention suitable for rectal administration are the known pharmaceutical forms for such administration, for example suppositories with cocoa butter or polyethylene glycol bases.

Compositions of the invention suitable for parenteral administration are the known pharmaceutical forms for such administration, for example sterile suspensions or sterile solutions in a suitable solvent.

Compositions for topical administration may comprise a matrix in which the pharmacologically active compounds of the present invention are dispersed so that the compounds are held in contact with the skin in order to administer the compounds transdermally. Alternatively the active compounds may be dispersed in a pharmaceutically acceptable cream or ointment base.

In some formulations it may be beneficial to use the compounds of the present invention in the form of particles of very small size, for example as obtained by fluid energy milling.

In the compositions of the present invention the active compound may, if desired, be associated with other compatible pharmacologically active ingredients.

The pharmaceutical compositions containing a therapeutically effective amount of a compound of formula 30 1 may be used to treat depression in human beings. In such treatment the amount of the compound of formula I administered per day is in the range 1 to 1000 mg preferably 5to 500 mg.

Compounds of formula I may be prepared by the reductive amination of ketones of formula 11 R4 CORI 35 R 5 RG 11 40 Examples of suitable reductive amination processes are given below-.a) for compounds of formula I in which R2 and R3 are H, by reaction of the ketone with an ammonium salt for example ammonium acetate and a reducing agent such a sodium cyanoborohydride, b) for compounds of formula I in which R3 is otherthan Hand R2 is H by reaction of the ketone with an amine of formula R3NH2 and a reducing agent such as sodium cyanoborohydride or sodium borohydride, c) for compounds of formula I in which neither R2 nor R3 is hydrogen by reaction of the ketone with an amine of formula HNR2R3 and either formic acid or a reducing agent such as sodium cyanoborohydride, d) for compounds of formula I in which neither R, nor R2 contains a reducible double bond by catalytic hydrogenation at elevated temperature and pressure of a mixture of the ketone and an amine of formula HNR2R3- Compounds of formula I in which neither R2 nor R3 is H may be prepared by reacting ketones of formula 11 with formamides of formula HCONR2133 for example in the presence of formic acid.

Compounds of formula I may be prepared by the reduction of compounds of formula III R4 Z p- R.5 RG 0 4 a X 3 GB 2 128 991 A 3 in which a) Z is a group of formula -CR,=NOH or an ester or ether thereof to give compounds of formula] in which R2 and R3 are H; b) Z is a group of formula -CR1=1\1R2 (where R2 is not a reducible group) to give compounds of formula 1 in which R3 is H; c) Z is a group of formula -CR,=NY in which Y represents a metal-containing moiety derived from an organometallic reagent to give compounds of formula 1 in which R2 and R3 are H.

Suitable reducing agents for the above reactions include sodium borohydride, sodium cyanoborohydride, or lithium aluminium hydride.

In (c) above Y is preferably MgCI or MgBr derived from a Grignard reagent or U derived from an organolithium compound.

Compounds of formula 1 in which R3 is H may be prepared bythe reaction of an organometallic reagent for example a Grignard reagent of formula R,MgX where X is Cl, Br or 1 or an organolithium compound of formula R, Li with imines of formula IV R4. CH=NR2 R Re ly followed by hydrolysis to give secondary amines of formula 1.

Compounds of formula I in which R2 and R3 are H maybe prepared by the decarboxylative rearrangement, for example using iodosobenzenebistrifluoroacetate or by a Hofmann reaction using bromine in alkaline solution, of amides of formula V RL. CHR1.COM2 30 5Q-h R6 Y 35 Compounds of formula 1 in whichR2 and R3are H may be prepared bythe decarboxyiative rearrangement of acyl azides in the Curtius reaction. The acyl azides may be formed for example by reaction of acid 40 chlorides of formula VI with sodium azide.

R4 CHRICOU R6 X Compounds of formula I in which R2 and R3 are H may be prepared by a Schmidt reaction in which 50 carboxylic acids of formula VII react with hydrazoic acid R4 CHRI.COOH R 5 IRS TX Compounds of formula 1 in which R3 is. H may be prepared by hydrolysis for example acid hydrolysis of compounds of formula 1 in which R3 is formy].

Compounds of formula 1 in which R3 is methyl may be prepared by reduction of compounds of formula 1 in which R3 is fornnyl for example by lithium aluminium hydride or by sodium bis(2-methoxyethoxy)aiuminium 65 hydride.

4 GB 2 128 991 A 4 Compounds of formula 1 in which R3 is formyl may be prepared by the reductive amidation of ketones of formula ll for example with formamide and formic acid or with ammonium formate and formic acid or with a formamide of formula HCONHR2 and formic acid or with an amine of formula R2NH2 and formic acid. Compounds of formula 1 in which R3 is formyl may be prepared by the formylation of compounds of formula 1 in which R3 is H for example by reaction with methyl formate. Compounds of formula 1 in which R2 is other than H and R3 is fOrMY1 may be prepared by reacting compounds of formula 1 in which R2 is H and R3 is formy] with a compound of formula R2X where X is a leaving group such as a halo group in the presence of a base (for example sodium hydride).

Compounds of formula 1 in which one or both Of R2 and R3 is other than H may be prepared from compounds of formula 1 in which one or both of R2 and R3 are hydrogen by methods which are well known in10 the art for the conversion of primary to secondary or tertiary amines or for the conversion of secondary to tertiary amines. The following are given as examples of suitable processes:a) by alkylating primary amines of formula 1 to give secondary amines of formula 1 for example by a process which includes the steps of protecting the primary amine with a protecting group such a trifluoroacety], alkylating with an alkyl halide and removing the protecting group for example by hydrolysis; 15 b) by alkylating primary amines of formula 1, for example, with an alkyl halide to give tertiary amines of formula 1 in which R2 and R3 are the same; c) by alkylating secondary amines of formula 1, for example with an alkyl halide to give tertiary amines of formula 1 in which R2 and R3 may be different; d) by reacting primary amines of formula 1 with sodium borohydride and a carboxylic acid of formula CF13(CH2)aCOOH in which a is 0, 1 or 2 to give secondary amines of formula 1 in which R2 is a group of formula CH3(CH2)a+ 1 and R3 is H or tertiary amines of formula 1 in which both R2 and R3 are a group of formula C113(CH2)a+l; e) by reacting primary amines of formula 1 with formaldehyde and formic acid to give tertiary amines of formula 1 in which both R2 and R3 are methyl; f) by reacting secondary amines of formula 1 in which R3 is H with formaldehyde and formic acid to give tertiary amines of formula 1 in which R3 is methyl; g) by formylating primary amines of formula 1, for example by reaction with methyl formate to give compounds of formula 1 in which R3 is formyl and reducing the formamides, for example with lithium aluminium hydrideto give secondary amines of formula 1 in which R2 is Hand R3 is methyl; h) byformylating secondary amines of formula 1, for example by reaction with methyl formate, to give compounds of formula 1 in which R3 is formyl and reducing the formamides, for example with lithium aluminium hydride to give tertiary amines of formula 1 in which R3 is methyl; i) by acylating primary amines of formula 1, for example by reaction with an acyl chloride of formula R7COCI oran anhydride of formula (R7C0)20 in which R7 is an alkyl, alkenyl oralkynyl group and reducing 35 the resulting amides for example with lithium aluminium hydride to give secondary amines of formula 1 in which R2 is -CH2R7 and R3 is H; j) by acylating secondary amines of formula 1 in which R2 is H for example by reaction with an acyl chloride of formula R7COCI or an anhydride of formula (R7C0)20 and reducing the resulting amides for example with lithium aluminium hydride to give tertiary amines in which R2 is -CH2R7; k) by reacting primary amines of formula] with aldehydes of formula R8CHO in which R8 is an alkyl, alkenyl or alkynyl group and reducing the resulting imines for example with sodium cyanoborohydride or, if RI3 and R, do not contain reducible double bonds, by catalytic hydrogenation to give secondary amines of formula 1 in which R2 is -CH2R8 and R3 is H; 1) by reacting primary amines of formula 1 with ketones of formula R9COR10 in which R9 and Rio, which may 45 be the same or different are alkyl groups or R9 and Rio together with the carbon atom to which they are attached form an alicyclic ring and reducing the resulting imines for example with sodium cya n oborohyd ride or, if R,, R9 and Rio do not contain reducible double bonds, by catalytic hydrogenation to give compounds of formula 1 in which R3 is H and R2 is a group of formula Vill Rio 1 R9 - CH - Vill m) by reacting secondary amines of formula 1 in which R2 is H with aldehydes of formula R8CHO in which the group R8 has a hydrogen atom on the carbon atom adjacent the formyl group, and reducing the resulting enamines for example with sodium cyanoborohyd ride or, when R8 and R, do not contain reducible double 60 bonds, by catalytic hydrogenation to give secondary amines of formula 1 in which R2 is -CH2RE1; n) by reacting secondary amines of formula 1 in which R3 is H with ketones of formula R9COR10 in which one of the groups R9 and Rio has a hydrogen atom on the carbon atom adjaceritthe carbonyl group and reducing the resulting enamines for example with sodium cyanoborohydride or when R,, R9 and Rio do not contain reducible double bonds, by catalytic hydrogenation to give compounds of formula 1 in which R2 is a group of 65 formula Vill; GB 2 128 991 A 5 Compounds of formula I in which the group R, contains one or more double bonds may be reduced, for example by catalytic hydrogenation, to give compounds of formula I in which R, is a saturated heterocyclic group.

The group R, may be built up by methods well known in the art. For example, when R, is a heterocyclic ring containing four nitrogen atoms and is substituted by an alkyl group, compounds of formula I maybe 5 prepared from cyano compounds of formula IX CN 1 1 R4 LOR2R 3 R5p-'i RG ig:

for example by reaction of cyano compounds of formula IX with sodium azide and aluminium chloride to give compounds of formula 1 in which R, is a tetrazole group followed by alkylation.

The ketones of formula 11 may be prepared by the hydrolysis of compounds of formula Ill in which Z is 20 -CR, =NH or by the acid hydrolysis of imines of formula X 1 W4. UF N - 1 R5 P 1 1 RG X in which Y represents a metal-containing moiety derived from an organometallic reagent. The imines of 30 formula X may be prepared by the reaction of said organometallic reagent with cyano compounds of formula M R4, CN R5;p-h RG M Suitable organometallic reagents include Grignard reagents of formula R, MgX where X is Cl, Br or I (Y MgX) and organolithium compounds of formula R, Li (Y = Li).

Ketones of formula 11 may be prepared by the reaction of carboxylic acid derivatives such as amides or acid halides with an organometallic reagent for example by the reaction of an acid chloride of formula X11 R4 COM 'P-] 50 R5 RS 11r with a Grignard reagent of formula R,MgX where Xis Cl, Br or 1 at low temperatures or by the reaction of carboxylic acids of formula XIII R4 COOH p-h R; R6 with an organometallic reagent, for example an organolithiurn compound of formula RjLi.

Compounds of formula III in which Z is a group of formula -CR, =NOH or ethers or esters thereof may be 65 6 GB 2 128 991 A prepared by the reaction of hydroxylamine or an ether or ester thereof with ketones of formula 11.

Compounds of formula Ill in which Z is a group of formula -CR,=NR2 maybe prepared by the reaction of amines of formula R2NH2 with ketones of formula 11 or, when R2=H, by the hydrolysis of compounds of formu [a III in which Z is a group of formula -CR,= NY.

The preparation of compounds of formula III in which Z is a group of formula -CR,= NY has been described above in respect of compounds of formula X.

Imines of formula IV may be prepared by reaction of amines of formula RjNH2 with aldehydes of formula XIV 6 R 4 V- CHO R.

5, RG X17 Amides of formula V may be prepared by the reaction of ammonia with carboxylic acid derivatives for example acid chlorides of formula VI or they may be prepared from cyano compounds of formula XV for example by hydration with aqueous acids or by reaction with hydrogen peroxide in the presence of a base.

R4 CH ICN R5 19 h XT Carboxylic acids of formula VII and XIII may be prepared by the hydrolysis, for example basic hydrolysis, of cyano compounds of formula XV and XI respectively. Carboxylic acids of formula VII may be prepared by the reaction of amides of formula V with nitrous acid. Carboxylic acids of formula XIII may be prepared by the reaction of nitrous acid with the amides formed by (a) the reaction of ammonia with carboxylic acid derivatives for example acid chlorides of formula XII or (b) by the reaction of cyano compounds of formula XI with hydrogen peroxide in the presence of a base.

Cyano compounds of formula IX may be prepared by one of the following reactions:a) by the reaction of cyano compounds of formula X1 with an aluminium hydride, for example diisobutylaluminium hydride, to form compounds of formula Ill in which Z is a group of formula -CH=NAV13U2 followed by reaction of these compounds with cyanide ion and hydrolysis to givethe cyano compounds of formula IX in which both R2 and 23 are H, or b) by the reaction of aldehydes of formula XIV with an alkali metal cyanide and an amine of formula NHIR2R3.

Cyano compounds of formula XI may be prepared by the reaction of cyano compounds of formula XVI 40 R4. CH2 CN RS R6 m with a 1,3-disubstituted propane for example 1,3-di bromopro pane and a base such as sodium hydride. 50 Cyano compounds of formula XV may be prepared from the cyano compounds of formula XVII R 4 CH 2 XN R: 4 G - 45 m for example by reaction with a halide of formula RjX where X is chloro, bromo or iodo in the presence of a 60 base such a lithium diisopropylamide.

Cyano compounds of formula XV may also be prepared by reacting ketones of formula 11 with a reagent for introducing a cyano group such asp-toluene-sulphony[methyl isocyanide.

Cyano compounds of formula XVII may be prepared from cyano compounds of formula XI byfor example the following series of reactions:- 7 GB 2 128 991 A 7 a) hydrolysis of the cyano group to form a carboxylic acid of formula XIII oralcoholysis of the cyano group to form an ester of a carboxylic acid of formula XIII; b) reduction of the carboxylic acid or the ester thereof for example with lithium aluminium hydride of boranedimethyisulphide complex to form the corresponding alcohol; c) replacement of the hydroxy group of the alcohol by a leaving group for example aptoluenesulphonyloxy group and d) replacement of the leaving group with a cyano group.

Acid chlorides of formula XII and V[ may be prepared by the reaction of carboxylic acids of formula XIII and VII respectively with for example thionyl chloride.

Aldehydes of formula XIV may be prepared by methods well known to those skilled in the art. The following are given as examples of suitable methods:a) by the reduction of cyano compounds of formula XI with for example, di-tert-butylaluminium hydride or diisobutylaluminium hydride followed by hydroxlysis. b) by the reduction of carboxylic acid derivatives, for example i)by the reduction of tertiary amides formed by the reaction of secondary amines with acid chlorides of 15 formula XII, for example when the secondary amine is a dialkylamine using lithium cliethoxyaluminohydride as a reducing agent or when the secondary amine is ethyleneimine using lithium aluminium hydride as the reducing agent, ii) bythe reduction of acid chlorides of formula X11 for example, with lithium tri-tert20 butoxyaluminohydride.

c) by the oxidation of alcohols (prepared by the reduction of carboxylic acids of formula XIII) with, for example, chromium trioxide-pyridine complex in dichloromethane under anhydrous conditions.

Ketones of formula 11, the compounds of formula III, the imines of formula X, the amides of formula V, the acid chlorides of formula VI, the carboxylic acids of formula VII and the cyano compounds of formula XV are described herein as intermediates are novel compounds.

The therapeutic activity of the compounds of formula I has been indicated by assessing the ability of the compounds to reverse the hypothermic effects of reserpine in the following manner. Male mice of the Charles River CD1 strain weighing between 18 and 30 grammes were separated into groups of five and were supplied with food and water ad libitum. Afterfive hours the body temperature of each mouse was taken orally and the mice were injected intraperitoneally with reserpine (5 mg/kg) in solution in deionised water 30 containing ascorbic acid (50 mg/m I). The amount of I iquid injected was 10 ml/kg of body weight. Nine hours after the start of the test food was withdrawn but water was stil I available ad I ibitum.Twenty-fourhours after the start of the test the temperatures of the mice were taken and the mice were given the test compound suspended in a 0.25% solution of hydroxy ethyl cellulose (sold underthe trade name Cellosize QP 15000 by Union Carbide) in deionised water at a dose volume of 10 ml/kg of body weight. Three hours later the temperatures of all the mice were again taken. The percentage reversal of the reserpine-induced loss of body temperature is then calculated by the formula:

(T27 - T24) X 100 (T5 - T24 in which Tt is the temperature in degrees Celsius after t hours. The mean value for each g roup of f ive mice was taken at several dose rates to enable a value of the mean dose which causes a 50% reversal (ED50) to be 45 obtained. All the compounds which are the final products of the Examples hereinafter gave values of ED50 of mg/kg or less. It is widely understood by those skilled in the art that this test is indicative of compounds having antidepressant activity in humans.

The invention will now be illustrated by the following Examples which are given by way of example only.

All compounds were characterised by conventional analytical techniques and gave satisfactory elemental 50 analyses. All melting and boiling points are expressed in degrees Celsius.

Example 1

Thiophene (10 mi) was added to a solution of butyllithium in dry ether (60 mi) (prepared bythe reaction of lithium (1.8 g) and butyl-bromide (14 9) followed by filtration through glass wool) and the mixture heated 55 under reflux for 2 hours. A solution of 1-(4chlorophenyi)cyclobutanecarbonitrile (15 g) in dry ether (20 mi) was added dropwise and the mixture heated under reflux for 75 minutes. After cooling to - 1 O'C a mixture of ice and water (30 mi) and then ice-cold 5N hydrochloric acid (50 mi) were added. Toluene (100 mi) was added and the mixture heated under reflux for 3 hours. The toluene layer was separated, dried and the solvent removed by evaporation to give a residue which was distilled at 1WC at 0. 05 mm Hq to give [1-(4-chiorophenyi)cyclobutyll(thien-2-yi) ketone (m.p. 74-76'C).

A mixture of the ketone (2.77 g) prepared as above, formamide (10 mi) and 98% formic acid (2 mi) was heated at 190'C for 17 hours. The mixture was cooled and extracted with dichloromethane. The extract was washed, dried and the solvent removed to yield an oil which solidified to give N-formyI-[1 -chlorophenyl) cyclobutyll(thien-2-yi)methylamine (m.p. 114-119'C).

8 GB 2 128 991 A 8 The N-formy] compound (1.55 g) prepared as above was added to a mixture of concentrated hydrochloric acid (10 m]), water (10 mi) and diethyleneg lycold i methyl ether (20 mi) and the reaction mixture heated to 140'C for 4 hours 30 minutes. The reaction mixture was poured into water (300 mi), aqueous sodium hydroxide was added and the resulting basic mixture extracted with ether. The ether extract was washed with water and extracted with 1 M hydrochloric acid. The acid extract was washed with ether, basified with aqueous sodium hydroxide and extracted with ether. Hydrogen chloride gas was passed through the dried ether extract to give [1 -(4-chlorophenyi)cyclobutyll(thien-2-yi)- methylamine hydrochloride (m.p. 238-240OC).

Example2

A solution of 2-bromopyridine (12.3 g) in dry ether (80 m]) was added to a 1.55M solution of butyllithium in 10 hexane (30 mO at -78'C. The mixture was stirred at -78'C for one hour and a solution of 1-(4 chlorophenyi)cyclobutanecarbonitrile (8 g) in ether (8 mi) added and the temperature of the mixture was allowed to rise to ambient. After one hour a solution of sodium borohydride (3 g) in dry diethyleneglycol dimethyl ether (130 mi) was added and the mixture heated at 950C for two hours. Water (100 mi) was added and the mixture extracted with ether. The ether extract was extracted with 8N hydrochloric acid and the acid extractwashed with ether, basified with aqueous sodium hydroxide solution and extracted with ether. The ether extract was filtered through diatomaceous earth, dried and the solvent removed by evaporation. The residue was distilled in the range 1680-1800C at 0.2 mm Hg pressure to yield an oil which was dissolved in ether. Hydrogen chloride gas was passed through the ethereal solution and the resulting precipitate was heated with propan-2-ol to give [1-(4-chlorophenyi)cyclobutyil-(pyrid-2yi)methylamine dihydrochloride 20 (m.p. 240'-245'C (dec)).

In a similar manner to that described above the following compounds were prepared 2a) [1-(4-Chlorophenyi)cyclobutyll(pyrid-3yi)methylaminedihydrochloride(m.p.275 -280'C) 2b) '[1-(4-Chlorophenyi)cyclobutyll(pyrid-4yi)methylaminedihydrochloride(m.p.26 0-265'C) Example 3

A solution of 2-bromopyridine (4.8 g) in dry ether (30 mi) was added to a 1.7M solution of butyllithium in hexane (18 mi) at -780C with stirring. After one hour at that temperature a solution of 1-(4-biphenylyl) cyclobutanecarbonitffle (4 9) in a mixture of dry ether (80 mi) and dry tetrahydrofuran (10 m]) was added and the temperature allowed to rise to O'C. After cooling to -200C, methanol (20 m]) and then water (30 ml) were added dropwise. The aqueous mixture was extracted with ether and the ether extract washed, dried and evaporated to give [1 -(4-biphenyiyi)cyclobutyll(pyrid-2-yi)methanimine as an orange oil. The oil was dissolved in propan-2-ol (200 mi) and heated under refluxwith sodium borohydride (2.0 g) forfive hours.

Water was added and the propan-2-ol removed by evaporation. The aqueous residue was extracted with ether. Hydrogen chloride gas was passed into the dried ether extract to give a gum which was heated with propan-2-ol to give a white solid which was recrystallised from a mixture of methanol and propan-2-ol to give [1 -(4-bi p henylyl)cyclobutyl 1-(pyrid-2-y1) methyl am! ne dillydrochloride hydrate (m.p. 240'C (dec)).

In a similar manner to that described above compounds of formula XVIII listed in Table 1 were prepared.

(0 TABLE 1

HR,NH,.nHCt IM Example Ar R, n Melting point Notes oc 3a 3-trifl u orom ethyl phenyl 3-pyridyl 2 265'(dec) 3b 4-chlorophenyl 3-thioyl 1 253-255' (1)(2) 3c 4-ch loro-3,5-di methyl phenyl 2-pyridyl 2 238-242o (3) 3d 3,4-dichlorophenyl 2-pyridyl 2 271-273' (dec) (3) 3e 4-methylthiophenyl 3-pyridyl 1.1 253-257o (3)(4)(5) (6)(8) 3f 4-fluorophenyl 2-thienyl 1 230-233' (4) (5) (8) (9) 39 6-chloro-2-naphthyl 2-pyridyl 2 208-212' (3)(4)(5) (7)(8) 3h 4-chloro-2-fluorophenyl 3-pyridyl 2 276-279' (3) (4) (5) (8) G) m NJ r-i 00 m,R CD GB 2 128 991 A Notes to Table 1 (1) imine purified by distillation and isolated as its hydrochloride salt (2) the sodium borohydride was added in diethyleneglycoldimethyl ether (3) the sodium borohydride was added in ethanol 5 (4) carbonitrile added in ether solution (5) after reduction the solvent was removed by distillation and the residue dissolved in ether. The ether solution was then washed with water (6) salt contains 0. 67 moles of water (7) hernihydrate recrystallised from propan-2-ol (8) butyllithium added at -70'C; methanol added at -40'C (9) product recrystallised from a mixture of ethanol and petroleum ether (b.p. 60- 80'C).

Example 4

1 -Methyl pyrazole (4.8 g) was added to a mixture of dry ether (60 ml) and a 1.7M solution of butyllithium in hexane (30 mi) under nitrogen at a temperature of less than 50C. NNNfN'- Tetramethylethylenediamine (TMEDA) (8.3 g) was added and the mixture stirred at 0-50C for one and three quarter hours and then 1-(4- chlorophenyi)cyclobutanecarbonitrile (6.0 g) was added and the mixture stirred for 90 minutes at a temperature in the range 0 to 50C. Water was added and the reaction mixture extracted with ether. The extract was washed, dried and evaporated to give an oil which is [1 -(4- chlorophenyi)cyclobutyil(l- methyl pyrazol-5-y1)methani mine. The imine was stirred with a mixture of sodium borohydride (2 g) in diethyleneglycoldimethyl ether (100 mi) under nitrogen at 950C for two hours. The mixture was poured into water and extracted with ether. The extract was washed, dried and evaporated to give a residue which was dissolved in dry ether. Hydrogen chloride gas was passed through the ethereal solution to give a hydrochloride salt of [1-(4-chlorophenyi)cyclobutyll(l-methylpyrazol-5-yi)methylamine hydrochloride (m.p.

316-318'C) containing 1.25 moles of hydrochloride and 0.25 moles of water.

The compounds of formula XVIII listed in Table 2 were prepared in a similar mannerto that described above except that the reaction between the heterocycle and the butyllithium took place at 40'C. Other modifications of the above method are indicated by notes to Table 2.

c w TABLE 2

CHR1NH2.nKI Ar - __] Example Ar R, n N otes m.p. of HCL No. salt of amine 4a 4-chlorophenyl 5-methylfur-2-yl 1 (1)(5) 218-219'C(dec) 4b 4-chlorophenyl 2-furyl 1 (2)(5) 23WC (dec) 4c phenyl 2-thienyl 1 (2)(5) 225-230'C (dec) 4d 4-biphenylyi 2-thienyl 1 (1)(5)(6) 165-170'C 4e 4-chlorophenyl 1 -methyl pyrrol -2-yl 1 (3)(4) 4f 3,4-dichlorophenyl 1-methylimidazol-2-yi 2 (5)(7)(8) 259-261'C a) eu i; co co,R 12 GB 2 128 991 A 12 Notes (1) imine isolated as its hydrochloride salt (2) a solid containing the i mine or a salt of the imine was precipitated by the addition of a solution acetic acid in ether (3) the product was separated as the free base by high pressure liquid chromatography. The physical 5 constants of the product were not determined (4) the imine intermediate had an ED50 of less than 30 mg/kg when determined in the test described hereinbefore (5) NoTMEDAused (6) the sodium borohydride was added in propan-2-ol.

(7) the sodium borohydride was added in ethanol.

(8) the reaction between the heterocycle and the butyllithium took place at O'C.

Example 5

A solution of 2-bromothiophene (32.9 g) in dry ether (50 ml) was added dropwise to a stirred mixture of magnesium turnings (4.85 g) and ether (50 ml) under nitrogen. When all the magnesium had dissolved a solution of 1-(3,4- dichlorophenyl)cyclobutane-carbonitrile (30.6 g) in dry ether (200 ml) was added and the mixture stirred at 20'C for one hour and then heated under reflux for one hour. A solid formed which is believed to be [1-(3,4dichlorophenyl)cyclobutyll(thien-2-yl)methaniminylmagnesium bromide and was collected by f iltration. The solid was dissolved in ethanol (200 ml) and a solution of sodium borohydride (10 20 g) in ethanol (500 ml) added and the mixture heated under reflux for four hours. The mixture was cooled and water (200 ml) and then 5N hydrochloric acid added. The ethanol was removed by evaporation and the aqueous solution basified by the addition of 5N sodium hydroxide solution. The aqueous layer was extracted with ether and the extract dried. Hydrogen chloride gas was passed into the ethereal solution to give [1-(3,4-dichlorophenyl)cyclobuty[I)thien-2-yl)methylamine hydrochloride (m.p. 238-242'C).

The compounds of formula XVIII listed in Table 3 were prepared in a similar manner to that described above.

2- 5 CA) TABLE 3

HR,NH,.rtHCI Ar --, Example Ar R, Notes n M.P.

No.

5a 4-chlorophenyi 2-thienyl 1 238-240'C 5b 4-chlorophenyl 1 -methyl i midazol-2-yl (1)(2)(4) 0 93-94'C 5c 2-naphthyl 1 -methyl i midazol-2-yl M(3)(4) 0 126-129'C 5d 4-methylphenyl 2-thienyl (5) 1 228-230'C 5e 4-methoxyphenyl 2-thienyl 1 192-195'C 5f 4-bromophenyl 2-thienyl 1 235-237'C 5g 4-iodophenyl 2-thienyl 1 228-230'C a) ca K) N) OD CD T 14 GB 2 128 991 A Notes (1) 1-methylimidazolylmagnesium bromide was prepared by a modification of the process described in R. Kalish et al. J. Het. Chem. 1953 20 p. 702- 707 (2) the free base was obtained by distillation (boiling point range 160 to 170' at 0.1 mm Hg) and 5 recrystallised from cyclohexane (3) the sodium borohydride was in solution in diethyleneglycoldimethyl ether (4) Grig na rd reagent made in tetrahydrof u ran solvent (5) iminy1magnesium bromide not isolated as a solid. The ether was removed by evaporation and the residue heated under a nitrogen atmosphere at 90-950C for an hour. The treated residue was dissolved in 10 ethanol.

14 Example 6

A solution of 4-methylthiazole (4.95 g) in ether (5 m]) was added to ethyimagnesium bromide prepared under nitrogen from magnesium turnings (1.2 g) and ethyl bromide (5.5 g) in ether (40 m[). Ayell ' ow precipitate was formed which dissolved when the ether was replaced by tetrahydrofuran (70 mi).

1-(4-Chlorophenyi)cyclobutanecarbonitrile (6.0 g) was added and the solvent replaced by toluene and the mixture heated at 900C for two hours. Water and 2N sodium hydroxide solution were added and the reaction mixture extracted with ether. The extract was dried and the solvents removed by evaporation. The residue was dissolved in ether and hydrogen chloride gas was passed into the solution to give a pale yellow solid which is believed to be [1-4-chlorophenyi)cyclobutyi](4-methyithiazol-2- yi)methanimine hydrochloride. This 20 saltwas heated at 95'C fortwo hours with a solution of sodium borohydride (2 g) in diethyleneglycol dimethylether (100 ml). Water and 2N sodium hydroxide solution were added and the reaction mixture extracted with ether. The extract was dried and the solvents removed by evaporation. The residue was dissolved in ether and hydrogen chloride gas was passed into the solution to give a yellow solid. This solid was converted into the free base which was purified by column chromatography on a florisil column eluted 25 with a mixture of ether and cyclohexane to give [1-(4- chlorophenyi)cyclobutyil(4-methyithiazol-2-yi)methylamine which was converted into a hydrochloride salt [m.p. 230232'C(dec)l containing 1.5 moles of hydrochloride by dissolving the freebase in ether and passing hydrogen chloride gas through the solution.

Example 7

The product of Example 5(a) in the form of its free base (2.0 g), 98% formic acid (8 mi) and 37-40% aqueous formaldehyde solution (16 mi) was stirred at 20'C for one hour and then heated to 55-60'C for one hour and volatile materials were evaporated at 95'C and atmospheric pressure. The residue was basified with aqueous sodium hydroxide solution and extracted with ether. Hydrogen chloride gas was bubbled through the dried ethereal solution to deposit an oil. The solvent was evaporated and the residue triturated with dry ether and 35 clarified by filtration. The filtrate was evaporated and the residue triturated with dry acetone to give N,N-di m ethyl-[ 1 -(4-ch lo roph enyl)cycl obutyil-(th ien-2-y1) methyl am in e hydrochloride (m.p. 185-190'C).

Example 8

Acetic anhydride (5 m[) was added to a mixture of the product of Example 5(a) in the form of its free base (3 40 g) and crushed ice (5 g) and the resulting mixture stirred for 5 minutes. Aqueous sodium hydroxide (5N) was added and the resulting basic mixture extracted with ether. The ether extract was washed with water, dried and the ether removed by evaporation to give a residue which was triturated with petroleum ether (b.p.

60-80'C) to give a solid which was crystallised from petroleum ether (b.p. 80-1 OOOC) to give N-acety]-[1 -(4chlorophenyi)cyclobutyil-(thien-2-yi)methylamine (m.p. 105-108'C).

Borane-dimethyisulphide complex (2 mi) was added dropwise to a solution of the Macetyl compound (prepared as above) (1.5 9) in dry tetrahydrofuran. The mixture was stirred for 30 minutes at 20'C and at 40- 45'C for 10 minutes. Water was added to the cooled reaction mixture which was then extracted with ether. Hydrogen chloride gas passed into the dried ether extract to give a solid which was heated with boiling ether. The material which did not dissolve was n-ethyi-[1-4chlorophenyi)cyclobutyil-(thien-2-yi)methylamine hydrochloride (m.p. 204207OC).

Example 9

A 1.7M solution of butyilithium in hexane (30 m]) was added under nitrogen to a stirred solution of diisopropylamine (5.2 g) in dry ether (20 mi) at 20'C. After 20 minutes the mixture was cooled to -20'C and a 55 solution of 1,3-dithiane (6 g) in dry ether (50 m]) added dropwise. A solution of 1-(4-ch 1 o ro phenyl) cyclobutane carbonitrile (6 g) in dry ether (20 mi) was added. The temperature was maintained at O'C for 20 minutes. Sodium borohydride (2 g) in dry diethyleneglycol dimethyl ether (150 mi) was added and the mixture heated at 95'C fortwo hours. Waterwas added and an ether extraction performed. The extractwas washed, dried and evaporated to yield a residue which was dissolved in ether. [1-(4-Chlorophenyi) cyclobutyl 1 (1,3-dith ian-2-y1) methyl am i ne hydrochloride (m.p. 165167oC (dec)) was precipitated by passing hydrogen chloride gas into the ether extract.

GB 2 128 991 A 15 Example 10

The product of Example (4)b (1.49 g) was dissolved in absolute ethanol (45 ml) and Raney nickel (approximately 3 ml) added. The mixture was stirred under an atmosphere of hydrogen for two hours and thirty minutes and the reaction mixture was filtered and the solvent removed by evaporation. The residue was dissolved in dilute hydrochloric acid and the solution basified. A white solid formed which was extracted into ether. The extract was dried and yielded [1 -(4-ch lo ro phenyl)cyclobutyll (tetra hyd rofu r-2-yl) m ethyla m i ne as an oil (Physical constants not determined).

Example 11

The product of Example 3 in the form of its free base was mixed with methyl formate and the mixture 10 stored at ambient temperature for 4 days. A gum formed which was triturated with petroleum ether with warming to give N-formyi-[1 -(4-bi p henylyl)cycl obutyil (pyri d-2-yi) methyl am i ne (m.p. 1 01'C).

Example 12 A 1 M solution of diisobutylaluminium hydride in hexane (200 m]) was added at -30'C to a solution of 1-(4chlorophenyi)cyciobutanecarbonitrile (38.3 9) in ether (200 mi) under nitrogen. The temperature was maintained at -5'C for two hours and then cooled to -20'C. Finely powdered sodium cyanide (12.25 g), finely powdered ammonium chloride (51.1 g) and dimethyisulphoxide (200 mi) were added sequentially and the mixture warmed to ambient temperature. 18- Crown-6(1 g) was added and them ixturestirred for 16 20 hours. After 5 hours rapid stirring, water (8 mi) was added dropwise and the stirring continued for 16 hours. 20 Water (100 mi) was then added in ten portions and the reaction mixture poured into 2N aqueous sodium hydroxide solution (500 mi). An ether extraction was performed and the extract dried. Hydrogen chloride gas was passed through the extract to give a pale yellow solid which was recrystallised from propan-2-ol to give 1-amino-l[1-(4-chlorophenyl)-cyclobutyllacetonitrile hydrochloride hydrate. 25 Finely powdered sodium azide (19 g) was added to a solution of aluminium chloride (13.35 g) in tetrahydrofuran (120 mi) under nitrogen and the mixture heated under reflux for 30 minutes. The acetonitrile salt (13.75 g) prepared as described above was added and the mixture heated under reflux with stirring for 70 hours. After cooling the reaction mixture, water (200 mi), concentrated hydrochloric acid (200 mi) and water (500 mi) were added sequentially and the mixture heated to 90-95' under vacuum to reduce the volume. An oil and sodium chloride separated from the reaction mixture. These were discarded and the filtrate was evaporated to give a white solid which was stirred with isopropanol (200 ml) and the mixture filtered. The solvent was removed from the filtrate and the residue dissolved in water (150 mi). A solid was precipitated by the addition of aqueous ammonia solution and a sample of this solid (5 g) in finely ground form was added to a mixture of acetone (30 mi) and water (200 mi). The mixture was made strongly alkaline by adding potassium hydroxide solution and then climethyl sulphate (20 mi) was added dropwise over three hours. The 35 pH was maintained at 10. The mixture was stirred at ambient temperature for sixteen hours and excess concentrated aqueous ammonia solution added. The mixture was extracted with ether. The ether extract was dried and the ether removed. Hydrogen chloride gas was passed through an ethereal solution of the residue to give a solid which was dissolved in methanol. The methanol was removed by evaporation. The residue was dissolved in propan-2-ol and the solvent removed by evaporation to give a hydrochloride salt 40 containing 90% N-methyl-[11 -(4-chlorophenyi)cyclobutyll(l-methyi-5- tetrazoiyi)methylamine and 10% N methyl-[ 1 -(4-ch 1 o ro ph e nyi)cycl obutyl] (cyclo butyl] (2-m ethyl-5tetrazo lyl) methyla m in e. The salt contained 1.1 moles I-IC1 (m.p. 230'C(dec)).

Example 13

The product of Example 3(d) in the form of its free base (3 g) and cyclopentanone (1.65 g) were mixed at room temperature, then heated with stirring at 140'C for 18 hours. The mixture was then cooled to room temperature dissolved in the minimum amount of ethanol (200 ml), and treated with a suspension of sodium borohydricle (2 g) in ethanol (20 ml). The mixture was heated under reflux for 2 hours left at room temperature for 16 hours and the solvent removed. The residue was diluted with water, acidified with 2N hydrochloric acid, basified with 2N aqueous sodium hydroxide, and extracted with ether. The extracts were washed and dried and the solvent removed to leave an oil which was purified by chromatography to give a pale brown gum which was taken up in ether and saturated with hydrogen chloride to give N-1[1-(3,4 dichlorophenyl)cyclobutyl](2-pyridyl)methyllcyclopentylamine sesquihydrochloricle (m.p. 120-1220C).

Example 14

A mixture of the compound of Example 4f in the form of its free base (39), acetone (1 g), sodium cyanoborohydride (1.1 9) and methanol was stirred at ambient temperature for seven days. The solvent was removed by evaporation and water added. The aqueous mixture was extracted with ether. Evaporation of the washed and dried extract gave a white solid which was purified by chromatography on a silica column 60 eluted with a mixture of ether (9 parts) and methanol (1 part) as eluant to give M{[1 -(3,4-dichlorophenyi) cyclobutyll (1 -methylimidazol-2-yi)methyi}-1 -methyl-ethyla mine (m.p. 98-100'C.

Example 15

In a similar mannerto that described in Example 14, N-{[1-(3,4dichlorophenyi)cyclobutyll(pyrid-2-yi)- 65 16 GB 2 128 991 A 16 methyl}-1-methylethylamine was obtained as an oil, the physical characteristics of which were not determined.

Example 16

Pharmaceutical compositions containing any one of the compounds of formula 1 disclosed in Examples 1 5 to 15 are prepared in the following manner.

Example 16(a)

Tablets are prepared from the following ingredients:

Active Ingredient Lactose Polyvinyl pyrrol idone Maize Starch Magnesium Stearate Parts by Weight 50.0 78.5 5.0 15.0 1.5 The active ingredient, the lactose and some of the starch are mixed and granulated with a solution of the polyvinylpyrrolidone in etahnol. The granulate is mixed with stearic acid and the rest of the starch and the 20 mixture is compressed in a tabletting machine to give tablets containing 50.0 mg of the active ingredient.

Example 16(b)

Capsules are prepared in the following way. A mixture of the active ingredient (45 parts by weight) and lactose powder (205 parts by weight) is filled into hard gelatin capsules, each capsule containing 45 mg of 25 the active ingredient.

Example 16(c)

In the preparation of enteric coated tablets, the tablets described in Example 16(a) are given a thin coat of shellac varnish, followed by 20 coats of cellulose acetate phthalate in a manner well known in the art. In a 30 similar manner the capsules of Example 16(b) may be provided with an enteric coating.

Example 16(d)

Vials containing a solution of water-soluble compounds of the present invention suitable for injection are prepared from the following ingredients:

Active Ingredient Mannitol Water, freshly distilled 11009 1100 g to 11 litres The active ingredient and mannitof are dissolved in some of the water and the volume of the solution is adjusted to 11 litres. The resulting solution is sterilised by filtration and filled into sterile vials each containing 1.65 mi of solution.

Claims

1. Compounds of formula 1 R4 CHRI.NIR2 R 3 R5 R8 I in which R, is a heterocyclic ring containing one or more heteroatoms selected from N, 0 and S; in which R2 is H, a straight or branched chain alkyl group containing 1 to 4 carbon atoms, an alkenyl group containing 3 to 6 carbon atoms, an alkynyl group containing 3 to 6 carbon atoms or a cycloalkyl group containing 3 to 7 carbon atoms; in which R3, is H, a straight chain alkyl group containing 1 to 3 carbon atoms or a formyl group in which R4, Rr, and R6 which may be the same or different, are H, halo, trifluoromethyl, hydroxy, an alkyl group containing 1 to 3 carbon atoms, an alkoxy group containing 1 to 3 carbon atoms, an alkylthio group containing 1 to 3 carbon atoms, phenyl or R4 and R5, together with the carbon atoms to which they are attached, form an optionally substituted second benzene ring; and their pharmaceutically acceptable salts.

Z I; 17 GB

2 128 991 A 17 2. Compounds of formula 1 as claimed in claim 1 wherein R, isa heterocyclic ring containing 5 or6 atoms, one of which is a heteroatom selected from N, 0 and S.

3. Compounds of formula 1 as claimed in claim 2 wherein R, is a fury[, thienyl, pyrroly], pyridyi, tetrahydrofuryl or tetra hyd roth ienyl ring.

4. Compounds of formula 1 as claimed in claim 1 wherein R, is a heterocyclic ring containing 5 or 6 5 atoms, two or more of which are similar heteroatoms selected from N, 0 and S.

5. Compounds of formula] as claimed in claim 4 wherein R, is an imidazolyl, pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazolyl, tetrazolyl or dithianyl group.

6. Compounds of formula 1 as claimed in claim 1 wherein R, is a heterocyclic ring containing 5 or6 atoms, two or more of which are different heteroatoms selected from N, 0 and S.

7. Compounds of formula 1 as claimed in claim 6 wherein R, is a thiazolyl ring.

8. Compounds of formula 1 as claimed in anyone of the preceding claims wherein R, is substituted by one or more alkyl groups, containing 1 to 3 carbon atoms, one or more halo groups, one or more alkoxy groups containing 1 to 3 carbon atoms or one or more trifluoromethyl groups.

9. Compounds of formula 1 as claimed in claim 1 wherein R, is afuryi, thienyi, pyridyi,tetrahydrofury], 15 dithianyl, methyifury], methylpyrroly], methyiimidazoiyl, methyl pyrazolyl, methyltetrazolyl or methyl thiazolyl group.

10. Compounds of formula 1 as claimed in anyone of the preceding claims wherein R2 is a methyl, ethyl, isopropyl, allyl, propyny], cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl group.

11. Compounds of formula 1 as claimed in anyone of the preceding claims wherein R3 is a methyl, ethyl, 20 propyl or isopropyl group.

12. Compounds of formula 1 as claimed in anyone of the preceding claims wherein R4, R5 and R6 which may be the same or different are selected from the group consisting of H, fluoro, chloro, bromo, iodo, methyl, methoxy and methylthio groups.

13. Compounds of formula 1 as claimed in anyone of claims 1 to 11 wherein R4 and R5 together with the carbon atoms to which they are attached form a second benzene ring optionally substituted by one or more halo groups, one or more alkyl groups containing 1 to 3 carbon atoms, one or more alkoxy groups containing 1 to 3 carbon atoms or the substituents on the second benzene ring together with the carbon atoms to which they are attached form a further benzene ring.

14. Compounds of formula] as claimed in claim 13 wherein the substituents on the second benzene ring 30 are fluoro, chloro, bromo, methyl or methoxy groups.

15. Compounds of formula 1 as claimed in claim 12 wherein R4 is a halo group, a methyl group, a methylthio group or a phenyl group and R5 is H or a halo group or R4 and R5 together with the carbon atoms to which they are attached form a second benzene ring.

16. Compounds of formula 1 as claimed in anyone of the preceding claims in the form of their hydrochloride, maleate, acetate, citrate, furnarate, tartrate, succinate, aspartate and glutamate salts.

17. Compounds of formula[ as claimed in claim 16 in the form of solvates.

18. Compounds of formula 1 selected from the group consisting of:

[1-(4-chlorophenyi)cyclobutyll(thien-2-yi)methylamine, [1-(4-chlorophenyi)cyclobutyll(pyrid-2-yi)methylamine, [1-(4chlorophenyl)cyclobutyll(pyrid-3-yi)methylamine, [1 -(4-ch 1 o rop henyl)cycl o butyll (pyrid-4-y1) methyl am i ne, [1-(4biphenylyi)cyclobutyll(pyrid-2-yi)methylamine, [ 1 -(3-trifl u oro methyl phenyl)cyclo butyl 1 (pyrid-3-y1)methyla mine, [1-(4-chforophenyi)cyclobutyll(thien-3-yi)methylamine, [ 1 -(4-ch loro-3, 5-d i methyl phenyl)cycl obutyl 1 (pyrid-2-y1) methyl am i ne, [1 -(3,4dichlorophenyi)cyciobutyll(pyrid-2-yi)methylamine, [1 -(4methyithiophenyi)cyclobutyll(pyrid-3-yi)methylamine, [1 -(4fluorophenyi)cyclobutyll(thien-2-yi)methylamine, [1 -(6-chloronaphth-2-yi)cyclobutyll(pyrid-2-yi)methylamine, [1 -(4-ch 1 oro-241 u orop henyl)cycl obutyll (pyrid-3-y1) methyl a mine, [1 -(4chlorophenyi)cyclobutyll(l -methyl pyrazol-5-yi)methylamine, [1 -(4chlorophenyl)cyclobutyil(5-methyifur-2-yi)methylamine, [1 -(4chlorophenyl)cyclobutyll(fur-2-yi)methylamine, (1 -phenylcyclobutyi)(thien-2-yi)methylamine, [1 -(4biphenyiyi)cyclobutyll(thien-2-yi)rnethylamine, [1 -(4chlorophenyi)cyclobutyll(l -methyl pyrrol-2-yi)methylamine, [1 -(3,4dichlorophenyi)cyclobutyi](1 -methyl im idazol-2-yi)methyla m in e, [1 (3,4-dichlorophenyi)cyclobutyll(thien-2-yi)methylamine, [1 -(4-chlorophenyi)cyclobutyll(l -methyl im idazol-2-yl)methylam ine, [1 -(naphth-2-yi)cyclobutyll(l -methylimidazol-2-yi)methylamine, [1 -(4-m ethyl phenyl)cycl obutyl 1 (th ien-2-yi)methyla m i ne, [1 -(4methoxyphenyi)cyclobutyll(thien-2-yi)methylamine, [1 -(4bromophenyi)cyclobutyll(thien-2-yi)methylamine, [1-(4-iodoph enyl)cycl o butyll (thien-2-y1) methyl am i ne, 18 GB 2 128 991 A 18 [1-(4-chlorophenyl)cyclobutyl](4-methylthiazol-2-yl)methylamine, N,Ndimethyl-[1-(4-chlorophenyl)cyclobutyl](thien-2-yl)methylamine, N-ethyl[l-(4-chlorophenyl)cyclobutyll(thien-2-yl)methylamine, [1-(4Chlorophenyl)cyclobutyl](1,3-dithian-2-yl)methylamine, [1 -(4-chlorophenyl)cyclobutyll (tetra hyd rofu r-2-yl)methylamine, Nformyl-[l-(4-biphenylyl)cyclobutyll(pyrid-2-yl)methylamine, N-methyl-[ 1 (4-ch I o roph enyl)cycl obutyl] (1 -methyl-5-tetrazolyi) m ethyl am i ne, N-methyl-[1 -(4-ch I o rophenyl)cycl obutyl] (2-methyl-5-tetr.azolyl) m ethyl am ine, N-1[1-(3,4-dichlorophenyl)cyclobutyl](2-pyridyl)methyllcyclopentylamine, 10 and pharmaceutically acceptable salts thereof.

19. Pharmaceutical compositions comprising a therapeutically effective amount of a compound of formula I as claimed in any one of the preceding claims together with a pharmaceutically acceptable diluent or carrier.

20. Pharmaceutical compositions as claimed in claim 18 in unit dosage form.

21. A process for the preparation of compounds of formula I comprising the reductive amination of 15 ketones of formula 11 R4 CORI t R 5 RG 11

22. A process as claimed in claim 21 wherein ketones of formula 11 are reacted with an ammonium salt and a reducing agent to give compounds of formula I-in which both R2 and R3 are H.

23. A process as claimed in claim 21 wherein ketones of formula 11 are reacted with an amine of formula R3NH2 and a reducing agent to give compounds of formula I in which R2 is Hand R3 is other than H.

24. A process as claimed in claim 21 wherein ketones of formula 11 are reacted with amines of formula HNR2133 and a reducing agent to give compounds of formula I in which R2 and R3 are both other than H.

25. A process as claimed in claim 21 wherein ketones of formula 11 are reacted with amines of formula HNR2R3 in which neither R, nor R2 contain a reducible double bond by catalytic hydrogenation at elevated temperature and pressure of a mixture of the ketones and amines.

26. A process for the preparation of compounds of formula I by the reduction of compounds of formula III R4 z RS RG II in which a) Z is a group of formula -CR, = NOH or an ester or ether thereof to give compounds of formula[ in which 45 R2 and R3 are H; b) Z is a group of formula -CR, =NR2 (where R2 is not a reducible group) to give compounds of formula 1 in which R3 is H; c) Z is a group of formula -CR, =NY in which Y represents a metal-containing moiety derived from an organometallic reagent to give compounds of formula 1 in which R2 and R3 are H:

27. A process as claimed in claim 26 wherein the reduction is preformed by a reducing agent selected from sodium borohydride, sodium cyanoborohydride or lithium aluminium hydride.

28. A process as claimed in claim 26 in which Yis a group of formula MgCI or Mg13rderivedfrom a Grignard reagent or Li derived from an organolithium compound.

29. A process for the preparation of compounds of formula 1 by the reaction of an organometallic reagent 55 for example a Grignard reagent of formula R1MgX where X is Cl, Br or 1 or an organolithium compound of formula R1Li with imines of formula W R4 CH=Q2 R 3 1 R6 ly 1 S 19 GB 2 128 991 A 19 followed by hydrolysis to give secondary amines of formula I in which R3 is H.

30. A process for the preparation of compounds of formula I prepared by the decarboxylative rearrangement, for example using iodosobenzenebistrifluoroacetate or by a Hofmann reaction using bromine in alkaline solution, of amides of formula V R4 CHRI,CONI-1p 5 p - --J R5 RG Y 10 to give compounds of formula 1 in which R2 and R3 are H.

31. A process for the preparation of compounds of formula 1 by the decarboxylative rearrangement of 15 acyl azides, formed by the reaction of acid chlorides of formula V1 R4 CHR1COU 20,Q- --I R6 YE with sodium azide, to give compounds of formula 1 in which R2 and R3 are H.

32. A process for the preparation of compounds of formula 1 by the reaction of hydrazoic acid with 25 carboxylic acids of formula V11 R4 CHRI.COOH RSP--h RG WI to give compounds of formula 1 in which R2 and R3 are H.

33. A process for the preparation of compounds of formula 1 in which R3 is H by the hydrolysis of compounds of formula 1 in which R3 is formyi.

34. A process for the preparation of compounds of formula[ in which R3 is methyl by the reduction of compounds of formula 1 in which R3 is formyl.

35. A process for the preparation of compounds of formula] in which R3 is formyl by the reductive 40 amidation of ketones of formula 11.

36. A process as claimed in claim 35 in which the ketones of formula 11 are reacted with (a)formamide and formic acid or (b) ammonium formate and formic acid to give compounds of formula 1 in which R2 is H.

37. A process as claimed in claim 35 in which the ketones of formula 11 are reacted with (a) aformamide of formula HCONHR2 and formic acid and (b) an amine of formula R2NH2 and formic acid to give compounds 45 in which R2 is other than H.

28. Compounds of formula] whenever prepared by a process as claimed in anyone of claims 21 to 37.

39. Pharmaceutical compositions containing a therapeutically effective amount of a compound of formula 1 as claimed in claim 38 together with a pharmaceutically acceptable diluent or carrier.

40. Compounds of formula] as claimed in anyone of claims 1 to 18 or38for use in thetreatment of depression.

41. Pharmaceutical compositions as claimed in claim 19,20 or 39 for use in the treatment of depression.

Printed for Her Majesty's Stationery Office, by Croydon Printing Company Limited, Croydon, Surrey, 1984. Published by The Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.