WO1993002050A1

WO1993002050A1 - Indoles

Info

Publication number: WO1993002050A1
Application number: PCT/EP1992/001625
Authority: WO
Inventors: Julian Blagg; Kelvin Cooper; Peter Lionel Spargo
Original assignee: Pfizer Corp Belgium; Pfizer Ltd Great Britain; Pfizer Inc
Current assignee: Pfizer Corp Belgium; Pfizer Ltd Great Britain; Pfizer Inc
Priority date: 1991-07-24
Filing date: 1992-07-20
Publication date: 1993-02-04
Anticipated expiration: 1994-01-24
Also published as: SK8494A3; IE922387A1; IL102544A0; ZA925546B; FI940310A0; HU9400199D0; FI940311A7; AU655662B2; CA2112689A1; CN1068817A; AU2327092A; BR9206306A; PT100718A; FI940311A0; EP0598750A1; NZ243687A; NO940237D0; MX9204342A; JPH06511483A; ZA925547B

Abstract

The present invention provides compounds of formula (I) and pharmaceutically acceptable salts thereof, wherein Y is C1-C6 alkylene optionally substituted by C1-C6 alkyl; R is H, OH, halo, C1-C4 alkyl or C1-C4 alkoxy; R?1, R2, R3 and R4¿ are each independently selected from H, C¿1?-C4 alkyl, C1-C4 alkoxy, OH, halo and CF3; one of R?6, R7 and R8¿ is a group of formula (a) or (b), and the remainder, together with R?5 and R9¿, are each independently selected from H, C¿1?-C4 alkyl, C1-C4 alkoxy, halo and halo(C1-C4)alkyl; R?10¿ is COOH, COOR11 or CONR?12R13; R11¿ is a biolabile ester-forming group; R?12 and R13¿ are each independently selected from H and C¿1?-C4 alkyl; R?14¿ is H, C¿1?-C6 alkyl, C3-C7 cycloalkyl or aryl; and ''aryl'', used in the definitions of R?6, R7, R8 and R14¿, means phenyl optionally substituted by C¿1?-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, OH, halo, CF3, halo(C1-C6 alkyl), nitro, amino, C2-C6 alkanamido, C2-C6 alkanoyl or phenyl: together with pharmaceutical compositions containing, processes for the preparation of and uses of, such compounds.

Description

INDOLES

This invention relates to indole derivatives which have steroid Sce-reductase inhibitory activity.

More particularly this invention relates to indoles, their preparation and their use as testosterone-5α- reductase inhibitors.

The androgen class of steroidal hormones, which includes testosterone, is responsible for the difference in the physical characteristics of males and females. Of all the organs that produce androgens, the testes produce these hormones in the greatest amounts. Over-production of these, hormones in the body results in many undesirable physical manifestations and disease states, e.g. acne vulgaris, alopecia, seborrhoea, female hirsutism, benign prostatic hypertrophy and male pattern baldness.

The principal androgen secreted by the testes is testosterone and it is the primary androgen present in male plasma. The principal mediator of androgenic activity in certain organs such as the prostate and sebaceous gland are the 5α-reduced androgens.

Testosterone is therefore the prohormone of 5α- dihydrotestosterone which is formed locally in the above organs by the action of testosterone-5α-reductase. The presence of elevated levels of dihydrotestosterone in many disease states has therefore focussed attention on the synthesis of testosterone 5α-reductase inhibitors.

Testosterone 5α-reductase inhibitors may also be useful in the treatment of human prostate

adenocarcinomas.

EP-A-0458207 discloses certain indole derivatives which have testosterone 5α-reductase inhibitory activity. The present invention provides compounds of the formula:-

and pharmaceutically acceptable salts thereof,

wherein Y is C₁-C₆ alkylene optionally substituted by

C₁-C₆ alkyl;

R is H, OH, halo, C₁-C₄ alkyl or C₁-C₄ alkoxy;

R¹, R², R³ and R⁴ are each independently selected from H, C₁-C₄ alkyl, C₁-C₄ alkoxy, OH, halo and CF₃; one of R⁶, R⁷ and R⁸ is a group of the formula:-

-OCH-Aryl or -CHO-Aryl, and the remainder, together with R⁵ and R⁹, are each independently selected from H, C₁-C₄ alkyl, C₁-C₄ alkoxy, halo and halo(C₁-C₄) alkyl; R¹⁰ is COOH, COOR¹¹ or CONR¹²R¹³;

R¹¹ is a biolabile ester-forming group ;

R¹² and R¹³ are each independently selected from H and C₁-C₄ alkyl ;

R¹⁴ is H, C₁-C₆ alkyl , C₃-C₇ cycloalkyl or aryl ; and "aryl" , used in the definitions of R⁶, R⁷ , R⁸ and R¹⁴, means phenyl optionally substituted by C₁-C₆ alkyl , C₁-C₆ alkoxy, C₂-C₆ alkenyl , OH, halo , CF₃, halo (C₁-C₆ alkyl) , nitro, amino, C₂-C₆ alkanamido , C₂-C₆ alkanoyl or phenyl .

In a further aspect of the present invention

Y is C₁-C₆ alkylene optionally substituted by C₁-C₆ alkyl ;

R is H, OH, halo , C₁-C₄ alkyl or C₁-C₄ alkoxy;

R¹ , R² , R³ and R⁴ are each independently selected from H, C₁-C₄ alkyl, C₁-C₄ alkoxy, OH, halo and CF₃; one of R⁶, R⁷ and R⁸ is a group of the formula : -

-O

CH-Aryl or -CHO-Aryl , and the remainder, together with R⁵ and R⁹, are each independently selected from H, C₁-C₄ alkyl,

C₁-C₄ alkoxy, halo and halo (C₁-C₄) alkyl;

R¹⁰ is COOH, COOR¹¹ or CONR¹²R¹³; R¹¹ is a biolabile ester-forming group;

R¹² and R¹³ are each independently selected from H and C₁-C₄ alkyl;

R¹⁴ is H, C₁-C₆ alkyl, C₃-C₇ cycloalkyl or aryl; and "aryl" , used in the definitions of R⁶, R⁷, R⁸ and R¹⁴, means phenyl optionally substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, C₂-C₆ alkenyl, OH, halo, CF₃, halo C₁-C₆ alkyl) , nitro , amino, C₂-C₆ alkanamido, C₂-C₃ alkanoyl or phenyl: with the provisos

i) when R⁷ is 1- (4- (2-methylpropyl) - phenyl) ethoxy, R, R¹, R^z, R³, R⁴, R⁵, R⁶, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH when the compound of the formula (I) is in the racemic form;

ii) when R⁷ is 1-(4-(2-methylpropyl)- phenyl)propoxy or 2,2-dimethyl-1-(4-(2- methylpropyl)phenyl)propoxy, R, R¹, R², R³, R⁴, R⁵, R⁶, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH or COOC₂H₅ when the compound of the formula (I) is in the racemic form;

iii) when R⁶ is 1-(3-(2-methylpropyl)phenyl)- ethoxy, R, R¹, R², R³, R⁴, R⁵, R⁷, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH or COOC₂H₅ when the compound of the formula (I) is in the racemic form; iv) when R⁷ is 1-(4-(2-methylpropyl)phenyl)- ethoxy, R⁵ and R⁶ are both methyl, R, R¹, R^z, R³, R⁴, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH or COOC₂H₅ when the compound of the formula (I) is in the racemic form;

v) when R⁷ is bis(4-(2-methylpropyl)phenyl)- methoxy, R, R¹, R², R³, R⁴, R⁵, R⁶, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH;

vi) when R⁶ is bis(4-(2-methylpropyl)phenyl)- methoxy, R, R¹, R², R³, R⁴, R⁵, R⁷, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH; and

vii) when R⁶ is 4-(2-methylpropyl)phenoxymethyl or 3- (2-methylpropyl)phenoxymethyl, R, R¹, R^z, R³, R⁴, R⁵, R⁷, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH or

COOC₂H₅.

Alkyl, haloalkyl, alkenyl and alkoxy groups

containing three or more carbon atoms and alkanamido and alkanoyl groups containing four or more carbon atoms may be straight- or branched-chain.

The term "halo" means fluoro, chloro, bromo or iodo.

The term "biolabile ester-forming group" is well understood in medicinal chemistry as meaning a group which forms an ester which can be readily cleaved in vivo to liberate the corresponding acid of the formula (I) wherein R¹⁰ is COOH. A number of such ester groups are well-known, for example in the penicillin area or in the case of the angiotensin-converting enzyme (ACE) inhibitor antihypertensive agents. Esters of the formula (I) wherein R¹⁰ is CO₂(C₁-C₈ alkyl) are steroid 5α-reductase inhibitors per se but, in general, where R¹⁰ is COOR such compounds are useful as pro-drugs to provide compounds of the formula (I) wherein R¹⁰ is COOH in vivo following oral administration. Such esters are also useful as intermediates for the

preparation of compounds" of the formula (I) wherein R¹⁰ is COOH.

The suitability of any particular ester-forming group for this purpose can be assessed by conventional in vitro or in vivo enzyme hydrolysis studies.

Examples of suitable biolabile ester-forming groups are alkyl (e.g. C₁-C₆ alkyl), alkanoyloxyalkyl (including alkyl, cycloalkyl or aryl substituted derivatives

thereof), arylcarbonyloxyalkyl (including aryl

substituted derivatives thereof), aryl, arylalkyl, indanyl and haloalkyl: wherein alkanoyl groups have from 2 to 8 carbon atoms and alkyl groups have from 1 to 8 carbon atoms, all of which may be straight- or branched- chain, and aryl means phenyl or naphthyl, both of which may be optionally substituted by C₁-C₄ alkyl, C₁-C₄ alkoxy or halo.

In addition to C₁-C₆ alkyl, specific examples of other biolabile ester-forming groups are benzyl, 1-(2,2- diethylbutyryloxy) ethyl, 2-ethylpropionyloxymethyl, 1-(2- ethylpropionyloxy) ethyl, 1-(2,4-dimethylbenzoyloxy) ethyl, α-benzoyloxybenzyl, 1-(benzoyloxy) ethyl, 2-methyl-1- propionyloxy-1-propyl, 2,4,6-trimethylbenzoyloxymethyl, 1-(2,4,6-trimethylbenzoyloxy) ethyl, pivaloyloxymethyl, phenethyl, phenpropyl, 2,2,2-trifluoroethyl, 1- or 2- naphthyl, 2,4-dimethylphenyl, 4-t-butylphenyl and 5- indanyl.

The pharmaceutically acceptable salts of the

compounds of the formula (I) are the acid addition and the base salts thereof. Suitable acid addition salts are formed from acids which form non-toxic salts and examples are the

hydrochloride, hydrobromide, hydroiodide, sulphate, bisulphate, phosphate, hydrogen phosphate, acetate, maleate, fumarate, lactate, tartrate, citrate, gluconate, benzoate, methanesulphonate, benzenesulphonate and p- toluenesulphonate salts.

Suitable base salts are formed from bases which form non-toxic salts and examples are the aluminium, calcium, lithium, magnesium, potassium, sodium, zinc and

diethanolamine salts.

For a review on suitable salts see Berge et al, J. Pharm. Sci., 66 , 1-19 (1977).

In the above definitions relating to the present invention:

Preferably Y is C₁-C₆ alkylene.

More preferably Y is methylene, propylene, butylene or pentylene.

Most preferably Y is propylene.

Preferably R is H or C₁-C₄ alkyl.

More preferably R is H or methyl.

Most preferably R is H. Preferably R¹, R², R³ and R⁴ are each H.

Preferably one of R⁶, R⁷ and R⁸ is a group of the formula:-

-OCH-Aryl or -CHO-Aryl, and the remainder, together with R⁵ and R⁹, are each independently selected from H and C₁-C₄ alkyl. More preferably R⁷ is a group of the formula:-

-OCH-Aryl or -CHO-Aryl, and R⁵, R⁶, R⁸ and R⁹ are each independently selected from H and C₁-C₄ alkyl.

Most preferably R⁷ is a group of the formula:- -O

CH-Aryl,

and R⁵, R⁶, R⁸ and R⁹ are each H.

Preferably R¹⁰ is COOH or COOR¹¹.

Most preferably R¹⁰ is COOH.

Preferably R¹¹ is C₁-C₆ alkyl.

Most preferably R¹¹ is ethyl.

Preferably R¹⁴ is H, C₁-C₄ alkyl, C₄-C₆ cycloalkyl or phenyl substituted by C₁-C₄ alkyl.

More preferably R¹⁴ is H, methyl, n-propyl,

cyclopentyl or 4-(n-propyl) phenyl.

Most preferably R¹⁴ is methyl.

Preferably "aryl" means phenyl optionally

substituted by from 1 to 3 substituents, more preferably means phenyl optionally substituted by 1 or 2

substituents and most preferably means phenyl optionally substituted by one substituent.

In a preferred aspect of the present invention

"aryl", means phenyl optionally substituted by C₁-C₆ alkyl or halo, more preferably means phenyl optionally

substituted by methyl, ethyl, n-propyl, isobutyl or chloro, yet more preferably means phenyl, 4-methylphenyl, 4-ethylphenyl, 4-(n-propyl) phenyl, 4-isobutylphenyl or 3,4-dichlorophenyl and most preferably means 4- isobutylphenyl. A compound of the formula (I) may contain one or more asymmetric carbon atoms and/or one or more alkenyl groups and may therefore exist in two or more

stereoisomeric forms. The present invention includes both the individual stereoisomers of the compounds of the formula (I) together with mixtures thereof. Separation of diastereoisomers or cis and trans isomers may be achieved by conventional techniques, e.g. by fractional crystallisation, chromatography or H.P.L.C. of a

stereoisomeric mixture of a compound of the formula (I) or a suitable salt or derivative thereof. An individual enantiomer of a compound of the formula (I) may also be prepared from a corresponding optically pure intermediate or by resolution, such as by H.P.L.C. of a racemate using a suitable chiral support or by fractional

crystallisation of the diastereoisomeric salts formed by reaction of a racemate with a suitable optically active acid or base.

A preferred group of compounds of the formula (I) is where one of R⁶, R⁷ and R⁸ is a group of the formula:-

and the remainder, together with Y, R, R¹, R², R³, R⁴, R⁵, R⁹, R¹⁰, R¹¹, R¹², R¹³ and "aryl" are as previously defined for a compound of the formula (I). Particularly preferred embodiments of the compounds of the formula (I) are

(R,S)-4-(3-[4-(1-[4-(2-Methylpropyl)phenyl]ethoxy)- benzoyl]indol-1-yl) butanoic acid,

(S)-4-(3-[4-(1-[4-(2-Methylpropyl)phenyl]ethoxy)- benzoyl]indol-1-yl)butanoic acid,

(R,S)-4-(2-Methyl-3-[4-(1-[4-(2-methylpropyl)- phenyl]ethoxy)benzoyl]indol-1-yl) butanoic acid and

(S)-4-(2-Methyl-3-[4-(1-[4-(2-methylpropyl)phenyl]- ethoxy)benzoyl]indol-1-yl) butanoic acid:

and the pharmaceutically acceptable salts thereof.

The compounds of formula (I) provided by the

invention may be prepared by the following methods:-

1) The compounds of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) may be prepared by cleavage of an ester of the formula:-

wherein R¹⁵ is a suitable ester-forming group and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I). A plethora of suitable ester-forming groups that may be cleaved to provide the corresponding carboxylic acid are known to the skilled man, see, e.g., T.W. Greene and P.G. Wuts, "Protective Groups in Organic Synthesis", Wiley-Interscience (2nd edition, 1991).

Where R¹⁵ is an ester-forming group that may be removed by hydrolysis, e.g. C₁-C₆ alkyl or an

alternative biolabile ester-forming group as

previously defined (i.e. a compound of the formula (I) wherein R¹⁰ is COOR¹¹), the hydrolysis may be carried out under acidic or basic conditions, e.g. using an aqueous solution of either a suitable mineral acid or a suitable inorganic base.

Preferably the hydrolysis is carried out under basic conditions.

In a typical procedure an ester of the formula (II) is treated with an aqueous solution of a suitable base, e.g. sodium or potassium hydroxide, and in the presence of a suitable organic co-solvent, e.g.

tetrahydrofuran or a C₁-C₄ alkanol such as methanol. The hydrolysis is typically carried out at from room temperature to the reflux temperature and preferably is carried out at room temperature. The product is obtained as a base salt which may be converted to the carboxylic acid by acidification in the work-up procedure.

Where R¹⁵ is an ester-forming group that may be removed by reduction, e.g. benzyl, the reduction may be carried out by catalytic hydrogenation using, e.g., palladium-on-charcoal, as the catalyst. 2) The compounds of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) may be prepared by hydrolysis of a compound of the formula (I) wherein

R ¹⁰ is CONR¹²R¹³ and Y, R, R¹ to R⁹, R¹² and R¹³ are as previously defined for a compound of the formula (I).

The hydrolysis may be carried out under acidic or basic conditions, e.g. using an aqueous solution of either a suitable mineral acid, e.g. hydrochloric or sulphuric acid, or a suitable inorganic base, e.g. sodium or potassium hydroxide, at from room

temperature to the reflux temperature. When basic hydrolysis conditions are used the product is obtained as a base salt which may be converted to the carboxylic acid by acidification in the work-up procedure.

3) The compounds of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) may be prepared by hydrolysis of a compound of the formula:-

wherein Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) and R¹⁶ is H or C₁- C₄ alkyl.

The hydrolysis may be carried out under acidic or basic conditions, e.g. using an aqueous solution of either a suitable acid, e.g. hydrochloric or acetic acid, or a suitable inorganic base, e.g. sodium or potassium hydroxide, at from room temperature to the reflux temperature. When basic hydrolysis

conditions are used the product is obtained as a base salt which may be converted to the carboxylic acid by acidification in the work-up procedure.

4) The compounds of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) may be prepared by hydrolysis of a compound of the formula:-

wherein Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) .

The hydrolysis may be carried out under acidic or basic conditions, e.g. using an aqueous solution of either a suitable acid, e.g. hydrochloric or sulphuric acid, or a suitable inorganic base, e.g. sodium or potassium hydroxide, at from room

temperature to the reflux temperature. When basic conditions are used hydrogen peroxide may optionally be present and also the product is obtained as a base salt which may be converted to the carboxylic acid by acidification in the work-up procedure.

5) The compounds of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) may be prepared by acidic hydrolysis of a compound of the formula:-

wherein Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) and R¹⁷ and R¹⁸ taken together represent ethylene, said ethylene group being optionally substituted by phenyl or C₁-C₄ alkyl (preferably methyl). Preferably R¹⁷ and R¹⁸ taken together represent -CH₂C(CH₃)₂-.

The hydrolysis may be carried out using an aqueous solution of a suitable acid such as hydrochloric acid at from room temperature to the reflux

temperature.

6) The compounds of the formula (I) wherein R¹⁰ is CONH₂ and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) may be prepared by partial hydrolysis of a compound of the formula (IV) wherein Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I). The hydrolysis may be carried out using concentrated sulphuric acid at from 0°C to room temperature.

7) The compounds of the formula (I) wherein R¹⁰ is COOR¹¹ and Y, R, R¹ to R⁹ and R¹¹ are as previously defined for a compound of the formula (I) may be prepared by esterification of a compound of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) with an alcohol of the formula R¹¹OH wherein R¹¹ is as previously defined for this method. The reaction may be carried out under classical esterification conditions such as by using an excess of the alcohol and with acid catalysis, e.g. by sulphuric acid or p-toluenesulphonic acid, at from room temperature to the reflux temperature. The water generated during the reaction may be removed by azeotropic distillation or by the use of a dehydrating agent or a molecular sieve.

The esterification may also be carried out by reacting the acid with the alcohol in the presence of a dehydrating agent, e.g.

dicyclohexylcarbodiimide or diethylazodicarboxylate/ triphenylphosphine (see O. Mitsunobu, Synthesis, 1981, 1).

Alternatively the esterification may be carried out by first forming an activated ester or imidazolide derivative of the carboxylic acid, followed by reaction of the activated ester or imidazolide in situ with the alcohol of the formula R¹¹OH. An activated ester may be formed by reacting the carboxylic acid with 1-hydroxybenzotriazole in the presence of a suitable dehydrating agent, e.g. 1-(3- N,N-dimethylaminopropyl)-3-ethylcarbodiimide, and in a suitable solvent, e.g. dichloromethane, at room temperature. An imidazolide may be formed by

reacting the carboxylic acid with 1,1'- carbonyldiimidazole in a suitable solvent, e.g.

dichloromethane, at room temperature.

8) The compounds of the formula (I) wherein R¹⁰ is COOR¹¹ wherein Y, R, R¹ to R⁹ and R¹¹ are as previously defined for a compound of the formula (I) may be prepared by reaction of a compound of the formula:-

wherein Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) and Z¹ is a

suitable leaving group, e.g. chloro or bromo, with an alcohol of the formula R¹¹OH wherein R¹¹ is as previously defined for this method.

The reaction may be carried out in the presence of an acid acceptor, e.g. pyridine, and in a suitable solvent, e.g. dichloromethane, at from 0°C to room temperature.

9) The compounds of the formula (I) wherein R¹⁰ is COOR¹¹ wherein Y, R, R¹ to R⁹ and R¹¹ are as previously defined for a compound of the formula (I) may be prepared by reaction of a base salt of a compound of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) (i.e. a carboxylate base salt) with a compound of the formula R¹¹Z² wherein R¹¹ is as

previously defined for a compound of the formula (I) and Z² is a suitable leaving group, e.g. halo, preferably bromo or iodo, or p-toluenesulphonyloxy. Preferred base salts of the compounds of the formula (I) for use in this method are the sodium and potassium salts. The reaction may be carried out in a suitable solvent, e.g. dimethylformamide or tetrahydrofuran, at from room temperature to the reflux temperature.

10) The compounds of the formula (I) wherein R¹⁰ is

CONR¹²R¹³ and Y, R, R¹ to R⁹, R¹² and R¹³ are as

previously defined for a compound of the formula (I) may be prepared by reaction of a compound of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) with an amine of the formula R¹²R¹³NH wherein R¹² and R¹³ are as previously defined for this method in the presence of a dehydrating agent, e.g. dicyclohexylcarbodiimide. The reaction may be carried out in a suitable organic solvent, e.g.

dichloromethane, at from room temperature to the reflux temperature.

Alternatively the reaction may be carried out by first forming an activated ester or imidazolide derivative of the carboxylic acid, followed by reaction of the activated ester or imidazolide in situ with the amine of the formula R¹²R¹³NH. Suitable procedures for the formation of an activated ester or imidazolide are described in method (7).

11) The compounds of the formula (I) wherein R¹⁰ is

CONR¹²R¹³ and Y, R, R¹ to R⁹, R¹² and R¹³ are as

previously defined for a compound of the formula (I) may be prepared by reaction of a compound of the formula (VI) wherein Y, R, R¹ to R⁹ and Z¹ are as previously defined for a compound of the formula (VI) with an amine of the formula R¹²R¹³NH wherein R¹² and R¹³ are as previously defined for this method. The reaction may be carried out in the presence of an acid acceptor, e.g. pyridine, and in a suitable solvent, e.g. dichloromethane, at from 0°C to room temperature.

12) The compounds of the formula (I) wherein R¹⁰ is

CONR¹²R¹³ and Y, R, R¹ to R⁹, R¹² and R¹³ are as

previously defined for a compound of the formula (I) may be prepared by reaction of a compound of the formula (II) wherein R¹⁵ is a suitable ester-forming group, e.g. C₁-C₆ alkyl or an alternative biolabile ester-forming group as previously defined (i.e. a compound of the formula (I) wherein R¹⁰ is COOR¹¹) , or p-nitrophenyl, and Y, R and R¹ to R⁹ are as

previously defined for a compound of the formula (I) with an amine of the formula R¹²R¹³NH wherein R¹² and R¹³ are as previously defined for this method. The reaction may be carried out in a suitable solvent, e.g. a C₁-C₄ alkanol, at from room temperature to the reflux temperature. The reaction is usually carried using an excess of the amine and in a sealed

reaction vessel (e.g. a bomb).

13) The compounds of the formula (I) wherein R¹⁰ is COOH or CONR¹²R¹³ and Y , R, R¹ to R⁹, R¹² and R¹³ are as previously defined for a compound of the formula (I) may be prepared by acidic hydrolysis of a compound of the formula:-

wherein Y, R and R¹ to R⁹ are as previously defined for this method, R¹⁹ and R²⁰ are either each C₁-C₄ alkyl or when taken together represent C₂-C₃

alkylene, said alkylene group being optionally substituted by C₁-C₄ alkyl, and R²¹ is -OH, -OR²² wherein R²² is a suitable ester-forming group that may be removed by hydrolysis, e.g. C₁-C₆ alkyl or an alternative biolabile ester-forming group as

previously defined, or NR¹²R¹³ wherein R¹² and R¹³ are as previously defined for this method. The

hydrolysis may be carried out using a suitable acid, e.g. hydrochloric acid or p-toluenesulphonic acid, in the presence of water. A compound of the formula (VII) may be prepared by first forming the corresponding ketal of a compound of the formula (VIII) wherein R and R¹ to R⁹ are as previously defined for this method by reacting with the corresponding alcohol under acidic conditions, e.g. see T.W. Greene and P.G. Wuts, "Protective Groups in Organic Synthesis", Wiley-Interscience (2nd edition, 1991), followed by N-alkylation of the ketal by a similar procedure to that described in method (14) for alkylation of a compound of the formula (VIII).

14) All the compounds of the formula (I) wherein Y, R and R¹ to R¹⁰ are as previously defined for a

compound of the formula (I) may be prepared by alkylation of a base salt (i.e. the N-deprotonated form) of a compound of the formula:-

wherein R and R¹ to R⁹ are as previously defined for a compound of the formula (I), with a compound of the formula Z³-Y-COORⁿ or Z³-Y-CONR¹²R¹³ or with a base salt of a compound of the formula Z³-Y-COOH, as appropriate, wherein Y, R¹¹, R¹² and R¹³ are as previously defined for a compound of the formula (I) and Z³ is a leaving group, e.g. halo, preferably chloro, bromo or iodo, methanesulphonyloxy or p- toluenesulphonyloxy. The preferred base salts of the compounds of the formula

Z³-Y-COOH are the alkali metal and alkaline earth metal salts, e.g. the sodium and potassium salts.

The preferred base salts of the compounds of the formula (VIII) are the alkali metal salts, e.g. the sodium and potassium salts.

The reaction may be performed by initial

deprotonation of a compound of the formula (VIII) with a suitable base, e.g. sodium hydride, followed by reaction of the resulting anion with a compound of the formula Z³-Y-COOR¹¹, Z³-Y-CONR¹²R¹³ or a base salt of a compound of the formula Z³-Y-COOH, as required. The reaction may be carried out in a suitable solvent, e.g. N,N-dimethylformamide or tetrahydrofuran, at from 0°C to the reflux

temperature and preferably at about room

temperature. The reaction may also be carried out using potassium carbonate as the base and in 2- butanone or acetone as the solvent at about the reflux temperature of the solvent.

Alternatively the reaction may be carried out under phase transfer conditions where a suitable base is sodium or potassium hydroxide. Where a compound of the formula (I) wherein R¹⁰ is COOH is required the product is obtained as a base salt which may be converted to the carboxylic acid by acidification in the work-up procedure.

15) All the compounds of the formula (I) wherein Y, R and R¹ to R¹⁰ are as previously defined for a compound of the formula (I) may be prepared by acylation of an indole of the formula:-

or, where R is OH, a base salt thereof,

or of a base salt of an indole of the formula:

wherein Y, R and R¹ to R⁴ are as previously defined for a compound of the formula (I) and R²³ is either OR¹¹ or is NR¹²R¹³ wherein R¹¹, R¹² and R¹³ are as previously defined for a compound of the formula (I), with a compound of the formula:-

wherein R⁵ to R⁹ are as previously defined for this method and Z⁴ is a leaving group, e.g. halo, preferably chloro, and in the presence of a Lewis acid where R is not OH and optionally in the presence of a Lewis acid where R is OH. Suitable Lewis acids include aluminium chloride and

diethylaluminium chloride.

The reaction may be carried out in a suitable solvent, e.g. toluene, at from room temperature to the reflux temperature.

The preferred base salts of the indoles of the formula (X) are the alkali metal and alkaline earth metal salts, e.g. the sodium and potassium salts. Where a compound of the formula (I) wherein R¹⁰ is COOH is required the product is obtained as a base salt which may be converted to the carboxylic acid by acidification in the work-up procedure.

Where a compound of the formula (I) wherein R is OH is required the compounds of the formula (IX) and (X) must be in the form of an enolate salt.

Accordingly an indole of the formula (IX) where R is OH or a base salt of an indole of the formula (X) where R is OH should first be treated with one equivalent of a suitable base, e.g. calcium

hydroxide, to form an enolate salt which may then be acylated with a compound of the formula (XI), optionally in the presence of a Lewis acid.

Incorporation of an acidification step in the work- up procedure affords a compound of the formula (I) wherein R is OH.

16) The compounds of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) may be prepared by oxidative cleavage of a compound of the formula:-

wherein Z⁵ is -CH=CH₂, -CH=CH(C₁-C₄ alkyl), -CH=C(C₁- C₄ alkyl)₂ or -C≡CH and Y, R and R¹ to R⁹ are as previously defined for this method.

The reaction may be carried out by ozonolysis or by treatment with aqueous potassium permanganate solution.

17) The compounds of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) may be prepared by oxidation of a compound of the formula:-

wherein Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I). A suitable oxidising agent for this purpose is chromium

trioxide in pyridine.

18) The compounds of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) may be prepared by oxidation of a compound of the formula:- or

or a base salt thereof, wherein R²⁴ is H or OH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I). A suitable oxidising agent for this purpose is chromium trioxide-pyridine complex.

The oxidation may alternatively be carried out on a compound of the formula (XV) wherein R²⁴ is H using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as the oxidising agent. The oxidation may alternatively be carried out on a compound of the formula (XV) wherein R ²⁴ is OH using manganese dioxide as the oxidising agent or under the conditions of the Swern oxidation reaction.

The starting materials of the formula (XIV) or (XV) wherein R²⁴ is H may be prepared by reacting the corresponding 1H-indole-1-magnesium halide

derivative with a corresponding benzyl halide of the formula:-

wherein R⁵ to R⁹ are as previously defined for this method and Z⁶ is halo, preferably chloro or bromo, followed by N-alkylation of the indole by a similar procedure to that described in method (14).

A starting material of the formula (XIV) or (XV) wherein R²⁴ is OH may be prepared by reacting the corresponding 1H-indole-1-magnesium halide

derivative with a corresponding benzaldeeyde of the formula:-

wherein R⁵ to R⁹ are as previously defined for this method.

19) The compounds of the formula (I) wherein one of R⁶,

R⁷ and R⁸ is a group of the formula:-

-OCH-Aryl

and the remainder, together with Y, R, R¹ to R⁵, R⁹,

R ¹⁰ R¹⁴ and "aryl" are as previously defined for a compound of the formula (I), may be prepared by reaction of a compound of the formula:-

or a base salt thereof. wherein one of R²⁵, R²⁶ and R²⁷ is OH and the remainder of R 25 ,26 and R²⁷ are as previously defined in this method for the remainder of R⁶, R⁷ and R⁸, and Y, R, R¹ to R⁵, R⁹ and R¹⁰ are as previously defined for this method, with a compound of the formula:-

Z⁷-CH-Aryl .... (XIX) wherein R¹⁴ and "aryl" are as previously defined for this method and Z⁷ is a suitable leaving group, e.g. halo, preferably chloro, bromo or iodo,

methanesulphonyloxy or p-toluenesulphonyloxy.

The preferred base salts of the compounds of the formula (XVIII) are the sodium and potassium salts.

The reaction is preferably carried out using a base salt of a compound of the formula (XVIII) (i.e. a phenoxide) which may be generated in situ from the corresponding phenol of the formula (XVIII) using a suitable base, e.g. sodium or potassium hydroxide or sodium hydride, and in a suitable solvent, e.g.

ethanol or N,N-dimethylformamide, at from 0°C to the reflux temperature. The reaction may also be carried out using potassium carbonate as the base and in 2-butanone or acetone as the solvent at about the reflux temperature of the solvent.

20) The compounds of the formula (I) wherein R¹⁰ is COOR¹¹ or CONR¹²R¹³ and Y, R, R¹ to R⁹, R¹¹, R¹², R¹³, R¹⁴ and

"aryl" are as defined for method (19) may be

prepared by reaction of a compound of the formula

(XVIII) wherein R¹⁰ is COOR¹¹ or CONR¹²R¹³, as

appropriate, wherein R¹¹, R¹², R¹³ and Y, R, R¹ to R⁵ and R⁹ are as previously defined for this method and

R²⁵ to R²⁷ are as previously defined for a compound of the formula (XVIII) in method (19), with a compound of the formula:-

HO-CH-Aryl ....(XX) wherein R¹⁴ and "aryl" are as previously defined for this method, in the presence of a suitable

dehydrating agent, e.g. diethylazodicarboxylate/ triphenylphosphine. The reaction may be carried out in a suitable solvent, e.g. tetrahydrofuran, at from room temperature to the reflux temperature.

21) The compounds of the formula (I) wherein one of R⁶,

R⁷ and R⁸ is a group of the formula:-

-CHO-Aryl, and the remainder, together with Y, R, R¹ to R⁵, R⁹, R¹⁰, R¹⁴ and "aryl" are as previously defined for a compound of the formula (I), may be prepared by reaction of a compound of the formula:-

or a base salt thereof. wherein one of R²⁸, R²⁹ and R³⁰ is a group of the formula:-

-CH-Z⁸ and the remainder are as previously defined in this method for the remainder of R⁶, R⁷ and R⁸, Y, R, R¹ to R⁵, R⁹, R¹⁰ and R¹⁴ are as previously defined for this method and Z⁸ is as defined for Z⁷ in method (19), with a base salt of a compound of the formula:-

Aryl-OH ....(XXII) wherein "aryl" is as previously defined for this method.

A base salt of a compound of the formula (XXII) (i.e. a phenoxide) may be generated in situ from the corresponding phenol of the formula (XXII) using a suitable base, e.g. sodium or potassium hydroxide or sodium hydride, and in a suitable solvent, e.g.

ethanol or N,N-dimethylformamide, at from 0°C to the reflux temperature. The reaction may also be

carried by reacting a phenol of the formula (XXII) with a compound of the formula (XXI) in the presence of potassium carbonate and in a suitable solvent, e.g. 2-butanone, at up to, and preferably at, the reflux temperature of the solvent.

22) The compounds of the formula (I) wherein R¹⁰ is COOR¹¹ or CONR¹²R¹³ and Y, R, R¹ to R⁹, R¹¹, R¹², R¹³, R¹⁴ and "aryl" are as defined for method (21) may be

prepared by reaction of a compound of the formula:-

wherein one of R³¹ , R³² and R³³ is a group of the formula:-

-CH-OH

and the remainder are as previously defined in this method for the remainder of R⁶, R⁷ and R⁸, and Y, R, R¹ to R⁵, R⁹, R¹⁰ and R¹⁴ are as previously defined for this method, with a compound of the formula (XXII) wherein "aryl" is as previously defined for this method, in the presence of a suitable dehydrating agent, e.g. diethylazodicarboxylate/

triphenylphosphine. The reaction may be carried out in a suitable solvent, e.g. tetrahydrofuran, at from room temperature to the reflux temperature. All of the above reactions and the preparations of novel starting materials used in the preceding methods are conventional and appropriate reagents and reaction conditions for their performance or preparation as well as procedures for isolating the desired products will be well known to those skilled in the art with reference to literature precedents and the Examples and Preparations hereto.

A pharmaceutically acceptable salt of a compound of the formula (I) may be readily prepared by mixing together solutions of a compound of the formula (I) and the desired acid or base, as appropriate. The salt may precipitate from solution and be collected by filtration or is recovered by evaporation of the solvent.

The compounds of the formula (I) are steroid 5α- reductase inhibitors and they are therefore useful in the curative or prophylactic treatment of

diseases or conditions such as acne vulgaris, alopecia, seborrhoea, female hirsutism, benign prostatic hypertrophy and male pattern baldness.

Certain compounds of the formula (I) are also useful in the treatment of human prostate adenocarcinomas.

The compounds of the formula (I) may be tested in vitro for steroid 5α-reductase inhibitory activity using prostate tissue from rats or humans. The compounds of the formula (I) may be tested for potency in inhibiting rat steroid 5α-reductase using ventral prostate tissue from male rats. In

determining inhibitory potency against rat prostatic 5α-reductase the following procedure was employed:-

Rat prostates were minced into small pieces. The tissue was homogenised in Buffer A (20mM sodium phosphate, pH 6.5, buffer containing 0.32M sucrose and 1mM dithiothreitol) with a Brinkman Polytron (Kinematica GmBH, Luzern), and then homogenised with a motor driven (1000rpm) Potter Elvehjem (teflon-to- glass) homogeniser. Prostate particles were

obtained by centrifugation at 105,000G for 60 minutes. The pellet was washed in 4 volumes of Buffer A and recentrifuged at 105,000G. The

resulting pellet was dispersed in Buffer A (1ml per g of prostate tissue originally used) with a motor driven Potter Elvehjem homogeniser as described above. The particulate suspension was stored as 1ml samples at -70°C.

The following components, dissolved in Buffer B (40mM sodium phosphate buffer, pH 6.5), were added to a test tube: 500μl of [³H] -testosterone (1μCi, lnmol; Du Pont, NEN Research Products, Stevenage, U.K.), 100μl of 0.5mM NADPH, a compound of the formula (I) dissolved in 5μl of dimethyl sulphoxide, and Buffer B to give a final reaction volume of 1ml. The mixture was warmed to 37°C and the reaction started by addition of an aliquot of prostate particulate suspension. The reaction mixture was incubated at 37°C for 30 minutes and then quenched by addition with vigorous mining of 2ml of ethyl acetate containing 20μg each of

testosterone and 5α-dihydrotestosterone as carriers. The aqueous and organic layers were separated by centrifugation at 2000G for 10 minutes. The organic layer was transferred to a second test tube and evaporated to dryness under nitrogen. The residue was dissolved in 50-80μl of absolute ethanol and spotted onto a silica gel 60 F254 TLC plate (E.

Merck, Darmstadt, Germany) and developed in

chloroform:acetone (185:15).

The radiochemical content in the bands of the substrate (testosterone) and the product (5α- dihydrotestosterone) was determined with a RITA Radio TLC Analyser (Raytest Instruments Ltd.,

Sheffield, U.K.). The percent of recovered

radiolabel converted to 5α-dihydrotestosterone was calculated and used to determine enzyme activity. All incubations were conducted so that no more than 15% of substrate (testosterone) was converted to product.

The experimentally obtained data for a range of inhibitor concentrations was computer fitted to a sigmoidal dose-response curve and concentrations of compound giving 50% inhibition of 5ot-reductase activity (IC₅₀'s) were calculated using a SIGFIT program (De Lean, A., Munson, P.J. and Rodbard, D., American Journal of Physiology, 235. E97 (1978)).

The compounds of the formula (I) may be tested for potency in inhibiting human steroid 5ot-reductase using tissue from hyperplastic human prostates. In determining inhibitory potency against human

prostatic 5α-reductase the following procedure was employed:- Frozen human prostate tissue was pulverised in liquid nitrogen using a steel mortar and pestle. The powdered tissue was homogenised in 4 volumes of Buffer A (20mM sodium phosphate, pH 6.5, containing 0.32M sucrose, lmM dithiothreitol and 50μM NADPH) with an Ultra-Turrax (Janke and Kunkel GmBH & Co. , Staufen i . BR. , Germany) . The homogenate was

centrifuged at 500G for 5 minutes, to remove large particles of tissue, and the supernatant was then centrifuged at 100,000G for 1 hour. The resulting pellet was dispersed in Buffer A (1ml per g of prostate tissue originally used) with the Ultra- Turrax homogeniser. This particulate preparation was then filtered through 2 layers of cheesecloth and the filtrate was stored as 1ml samples at -70°C.

The following components, dissolved in Buffer B (20mM citrate phosphate buffer, pH 5.2), were added to a test tube: 500μl of [³H] -testosterone (1μCi, lnmol; Du Pont, NEN Research Products, Stevenage, U.K.), 100μl of NADPH regeneration system (5mM

NADPH, 50mM glucose 6-phosphate, 5 units/ml glucose 6-phosphate dehydrogenase), a compound of the formula (I) dissolved in 5μl of dimethyl sulphoxide, and Buffer B to give a final reaction volume of 1ml. The mixture was warmed to 37°C and the reaction started by addition of an aliquot of prostate particulate suspension. The reaction mixture was incubated at 37°C for 30 minutes and then quenched by addition with vigorous mixing of 2ml of ethyl acetate containing 20μg each of testosterone and 5α- dihydrotestosterone as carriers. The aqueous and organic layers were separated by centrifugation at 2000G for 10 minutes. The organic layer was transferred to a second test tube and evaporated to dryness under nitrogen. The residue was dissolved in 50-80μl of absolute ethanol and spotted onto a silica gel 60 F254 TLC plate (E. Merck, Darmstadt, Germany) and developed in chloroform:acetone

(185:15).

Sheffield, U.K.). The percent of recovered

The experimentally obtained data for a range of inhibitor concentrations was computer fitted to a sigmoidal dose-response curve and concentrations of compound giving 50% inhibition of 5α-reductase activity (IC₅₀'s) were calculated using a SIGFIT program (De Lean, A., Munson, P.J. and Rodbard, D., American Journal of Physiology, 235, E97 (1978)).

The compounds of the formula (I) may be tested for potency in inhibiting steroid 5α-reductase activity in human prostate adenocarcinomas using cell lines DU145 and HPC36M. In determining inhibitory potency against 5 ce-reductase the following procedure was employed:- Human prostate adenocarcinoma cell lines were grown in Dulbecco's Modified Eagles medium (DMEM)

containing 5% serum. The cells were recovered from the medium by centrifugation, washed in serum free DMEM and suspended at 5-10 x 10⁶ cells/ml. in serum free medium.

The following components were added to a test tube: 10μl of [³H]-testosterone (1μCi, 20 pmol) dissolved in ethanol (Du Pont, NEN Research Products,

Stevenage, U.K.) and 5μl of an ethanol solution of a compound of the formula (I). The ethanol was evaporated under nitrogen and the testosterone and the compound redissolved in 0.25ml of serum free medium containing 0.25μmol NADPH. The mixture was warmed to 37°C and the reaction started by addition of 0.25ml of cell suspension (1.2-2.5 x 10⁶ cells). The reaction mixture was incubated at 37°C for 2 hours and then quenched by addition with vigorous mixing of 1.5ml of ethyl acetate containing 20μg each of testosterone and 5α-dihydrotestosterone as carriers. The aqueous and organic layers were separated by centrifugation at 2000G for 10 minutes. The organic layer, containing testosterone and its metabolites, was transferred to a second test tube and evaporated to dryness under nitrogen. The residue was dissolved in 50-80μl of absolute

ethanol, spotted onto a silica gel 60 F254 TLC plate (E. Merck, Darmstadt, Germany) and developed in dichloromethane:acetone (185:15). The radiochemical content in the bands of the substrate (testosterone) and the product (5α- dihydrotestosterone) was determined with a RITA Radio TLC Analyser (Raytest Instruments Ltd.,

Sheffield, U.K.). The percentage of recovered radiolabel converted to 5α-dihydrotestosterone was calculated and used to determine enzyme activity. All incubations were conducted so that no more than 15% of substrate (testosterone) was converted to product.

The experimentally obtained data for a range of inhibitor concentrations was computer fitted to a sigmoidal dose-response curve and concentrations of compound giving 50% inhibition of 5α-reductase activity (IC₅₀'s) were calculated using a SIGFIT program (De Lean, A., Munson, P.J. and Rodbard D., American Journal of Physiology, 235, E97 (1978)).

For human use, the compounds of the formula (I) can be administered alone, but will generally be administered in admixture with a pharmaceutical carrier selected with regard to the intended route of administration and standard pharmaceutical practice. For example, they can be administered orally in the form of tablets containing such excipients as starch or lactose, or in capsules or ovules either alone or in admixture with excipients, or in the form of elixirs, solutions or suspensions containing flavouring or colouring agents. They can be injected parenterally, for example,

intravenously, intramuscularly or subcutaneously. For parenteral administration, they are best used in the form of a sterile aqueous solution which may contain other substances, for example, enough salts or glucose to make the solution isotonic with blood. For oral and parenteral administration to human patients, the daily dosage level of the compounds of the formula (I) will be from 0.01 to 20 mg/kg (in single or divided doses) and preferably will be from 0.1 to 10mg/kg except for the treatment of human prostate adenocarcinomas where doses of up to

20mg/kg may be used. Thus tablets or capsules of the compounds will contain from lmg to 0.5g of active compound for administration singly or two or more at a time, as appropriate. The physician in any event will determine the actual dosage which will be most suitable for an individual patient and it will vary with the age, weight and response of the particular patient. The above dosages are exemplary of the average case; there can, of course, be individual instances where higher or lower dosage ranges are merited, and such are within the scope of this invention.

Alternatively, the compounds of the formula (I) can be administered in the form of a suppository or pessary, or they may be applied topically in the form of a lotion, solution, cream, ointment or dusting powder. For example, they can be

incorporated into a cream consisting of an aqueous emulsion of polyethylene glycols or liquid paraffin; or they can be incorporated, at a concentration between 1 and 10%, into an ointment consisting of a white wax or white soft paraffin base together with such stabilizers and preservatives as aay be

required. The compounds of the formula (I) may also be administered together with an ot-antagonist (e.g. prazosin or doxazosin), an antiandrogen (e.g.

flutamide) or an aromatase inhibitor (e.g.

atamestane), particularly for the curative or prophylactic treatment of benign prostatic

hypertrophy.

Thus the invention further provides:- i) a pharmaceutical composition comprising a

compound of the formula (I), or a

pharmaceutically acceptable salt thereof, together with a pharmaceutically acceptable diluent or carrier;

ii) a compound of the formula (I), or a

pharmaceutically acceptable salt or composition thereof, for use as a medicament;

iii) the use of a compound of the formula (I), or of a pharmaceutically acceptable salt or

composition thereof, for the manufacture of a medicament for inhibiting a steroid 5α- reductase;

iv) the use of a compound of the formula (I), or of a pharmaceutically acceptable salt or

composition thereof, for the manufacture of a medicament for the curative or prophylactic treatment of acne vulgaris, alopecia,

seborrhoea, female hirsutism, benign prostatic hypertrophy, male pattern baldness or a human prostate adenocarcinoma; v) a method of treatment of a human to inhibit a steroid 5α-reductase which comprises treating said human with an effective amount of a compound of the formula (I) or with a pharmaceutically acceptable salt or composition thereof;

vi) a method of treatment of a human to cure or

prevent acne vulgaris, alopecia, seborrhoea, female hirsutism, benign prostatic hypertrophy, male pattern baldness or a human prostate adenocarcinoma which comprises treating said human with an effective amount of a compound of the formula (I) or with a pharmaceutically acceptable salt or composition thereof; and vii) novel intermediates of the formulae (IV),

(VIII) and base salts thereof, (XIII), (XIV), (XV) and base salts thereof, (XVIII) and base salts thereof, (XXI) and base salts thereof, (XXI) and base salts thereof and (XXIII).

The following Examples illustrate the preparation of the compounds of the formula (I):-

EXAMPLE 1

(R,S)-4-(3-[4-(1-[4-(2-Methylpropyl)phenyl]ethoxy)- benzoyl]indol-1-yl)butanoic acid

A solution of (R,S)-4-(3-[4-(1-[4-(2- methylpropyl)phenyl]ethoxy)benzoyl]indol-1-yl) butanoic acid ethyl ester (3.8g) (see Example 21) in

tetrahydrofuran (THF) (35ml) and methanol (35ml) was treated with 2N sodium hydroxide solution (35ml). After stirring at room temperature for 2 hours the mixture was cautiously concentrated in vacuo to a volume of about 50ml then cooled in an ice-bath and acidified with 2N hydrochloric acid solution. The acid phase was extracted with ethyl acetate (100ml), the organic extract dried (sodium sulphate) and concentrated in vacuo to provide the title compound as a white foam, (3.27g), m.p. 57°C. Found: C, 77.00; H, 6.88; N, 2.90; C₃₁H₃₃NO₄ requires:

C, 76.93; H, 6.88; N, 2.99%.

¹H-NMR (CDCl₃) : δ = 0.95 (d, 6H), 1.70 (d, 3H), 1.90 (m, 1H), 2.25 (m, 2H), 2.40 (t, 2H), 2.49 (d, 2H), 4.30 (t, 2H),

5.50 (q, 1H), 6.95 (d, 2H), 7.15 (d, 2H), 7.27-7.45 (m, 5H), 7.59 (s, 1H), 7.79 (d, 2H), 8.45 (m, 1H) ppm.

EXAMPLES 2 to 20

The following compounds of the general formula:-

or base salts thereof, were prepared by hydrolysis of the corresponding ethyl esters (see Examples 22 to 38 , 42 and 43) by similar methods to that used in Example l.

EXAMPLE 21

(R, S)-4-(3-[4-(1-[4-(2-Methylpropyl)phenyl]ethoxy)- benzoyl]indol-1-yl) butanoic acid ethyl ester

A suspension of sodium hydride (60% dispersion in oil, 716mg) in dry dimethylformamide (DMF) (15ml) at 0°C and under a nitrogen atmosphere was treated dropwise with a solution of 4-(3-[4-hydroxybenzoyl]indol-1-yl)butanoic acid ethyl ester (see Preparation 1) (5.24g) in dimethylformamide (30ml). After stirring for one hour at room temperature a solution of α-methyl-4-(2-methylpropyl)benzyl bromide (see Preparation 23) (3.95g) in dimethylformamide (5ml) was added to the mixture at 0°C. The resultant mixture was stirred overnight at room temperature. The reaction was partitioned between 1N hydrochloric acid solution (100ml) and ethyl acetate (200ml). The separated organic layer was washed successively with 1N sodium hydroxide solution (100ml), saturated aqueous brine (100ml) and then water (100ml). The organic layer was dried (MgSO₄) and concentrated in vacuo to provide a yellow oil. Column chromatography (silica, 4.1 hexane/ethyl acetate) provided, after evaporation of the appropriate fractions, the title compound, (3.8g). Found: C, 77.47; H, 7.29; N, 2.74; C₃₃H₃₇NO₄ requires: C, 77.63; H, 7.48; N, 2.73%.

¹H-NMR (CDCl₃) : 5 = 0.91 (d, 6H), 1.35 (t, 3H), 1.70 (d, 3H), 1.90 (m, 1H), 2.20 (m, 2H), 2.31 (m, 2H), 2.49 (d, 2H), 4.13 (q, 2H), 4.25 (t, 2H), 4.50 (q, 1H), 6.95 (d, 2H), 7.15 (d, 2H), 7.27- 7.45 (m, 5H), 7.55 (s, 1H), 7.88 (d, 2H), 8.45 (m, 1H) ppm.

EXAMPLES 22 to 32

The following compounds of the general formula:-

were prepared by alkylation of the corresponding phenol derivatives (see Preparations 1, 3 and 4) with the

corresponding alkyl bromides (see, e.g., Preparations 20 to 26) by similar methods to that used in Example 21.

EXAMPLE 33

(S)-4-(3-[4-(1-[4-(2-Methylpropyl)phenyl]ethoxy)- benzoyl]indol-1-yl) butanoic acid ethyl ester

A solution of 4-(3-[4-hydroxybenzoyl]indol-1-yl)- butanoic acid ethyl ester (see Preparation 1) (500mg), (R)-1-(4-[2-methylpropyl]phenyl) ethanol (see Preparation 17) (256mg) and triphenylphosphine (410mg) in THF (20ml) was treated with diethylazodicarboxylate (DEAD) (0.27ml) and the mixture stirred at room temperature overnight. Evaporation of the reaction mixture onto silica gel (5g) followed by flash chromatography (silica, 3:1 hexane/ ethyl acetate) gave, after evaporation of the appropriate fractions, the desired compound as a pale yellow gum, (413mg), m/z = 511 (M⁺). H.P.L.C. (Cyclobond DMP column eluting with 1:1 1% triethylammonium acetate, pH4.1/CH₃CN at 0.7ml/min.) rt= 86.09 min. (100%). 1H-NMR (CDCl₃) : δ = 0.95 (d, 6H), 1.25 (t, 3H), 1.70 (d, 3H), 1.85 (m, 1H), 2.20 (m, 2H), 2.30 (t, 2H), 2.45 (d, 2H),

4.10 (q, 2H), 4.25 (t, 2H), 5.40 (q, 1H), 6.95 (d, 2H),

7.15 (d, 2H) 7.25-7.40 (m, 5H), 7.55 (s, 1H), 7.75 (d, 2H), 8.35 (m, 1H) ppm.

The title compound may also be prepared by

resolution of the product of Example 21 using chiral HPLC (Chiralpak AD column, eluant = 9:1 hexane/ethanol, flow rate = 12ml/min.). The first eluted compound was (R)-4- (3-[4-(1-[4-(2-methylpropyl)phenyl]ethoxy)benzoyl]indol- 1-yl) butanoic acid ethyl ester, rt = 24min.,

+52.1° (c=2 in dichloromethane), and the second eluted compound was the title compound, rt = 27min.,

- 53.8° (c=2 in dichloromethane).

EXAMPLES 34 to 37

The following compounds of the general formula:-

were prepared by condensation of the corresponding phenols or alcohols (see Preparations 1, 2 and 27) with the corresponding phenols or alcohols (see, e.g.

Preparations 17 and 18) by similar methods to that used in Example 33.

EXAMPLE 38

4- (3- [4-Benzyloxybenzoyl]indol-1-yl ) butanoic acid ethyl ester

A cooled (0°C) suspension of sodium hydride (3.40g of a 55% dispersion in mineral oil) in dimethylformamide (50ml) was treated with a solution of 3-(4- benzyloxybenzoyl) indole (see Preparation 5) (20.0g) in dimethylformamide (100ml). The resultant orange

suspension was allowed to stir for 1 hour at 20°C. The mixture was cooled to 0°C and ethyl 4-bromobutyrate (11.0ml) was added. The mixture was stirred for 2 hours at room temperature, cooled to 0°C and treated with 1N aqueous hydrochloric acid (100ml) and ethyl acetate (200ml). The organic layer was separated and washed with water (100ml), 1N aqueous hydrochloric acid (100ml), saturated aqueous sodium bicarbonate (100ml) and brine (100ml). Evaporation of the ethyl acetate gave an orange gum which was purified by flash chromatography (silica, eluant = 3:1 hexane/ethyl acetate then 2:1 hexane/ethyl acetate) to give, after combination and evaporation of the appropriate fractions, the title compound (16.5g), m.p. 83°C. 1H-NMR (CDCl₃) : δ= 1.20 (t, 3H), 2.20 (q, 2H), 2.35 (t, 2H), 4.15 (q, 2H), 4.29 (t, 2H), 5.20 (s, 2H), 7.10 (d, 2H), 7.30- 7.47 (m, 8H), 7.62 (s, 1H), 7.85 (d, 2H), 8.40 (m, 1H) ppm.

EXAMPLES 39 to 43

The following compounds of the general formula:-

were prepared by similar methods to that used in Example 38 using the corresponding indoles (see Preparations 5 to 8) and the corresponding ethyl bromoalkanoates as the starting materials.

The following Preparations illustrate the

preparation of certain starting materials used in the previous Examples:-

PREPARATION 1

4-(3-[4-Hydroxybenzoyl]indol-1-yl) butanoic acid ethyl ester

A solution of 4-(3-[4-benzyloxybenzoyl]indol-1- yl) butanoic acid ethyl ester (see Example 38) (13.4g) in ethyl acetate (300ml) was hydrogenated at 4.15 x 10⁵ Pa (60 psi) in the presence of 10% palladium-on-charcoal (3g) at room temperature for 4 hours. The catalyst was removed by filtration of the reaction through a cellulose-based filter aid and the filtrate was

concentrated in vacuo to a pale pink solid. Trituration with cold diethyl ether gave a white powder, (8.24g). Found: C, 71.78; H,6.02; N,3.98; C₂₁H₂₁NO₄ requires:

C,71.44; H,6.04; N,3.94%.

¹H-NMR (CDCl₃) : δ = 1.25 (t, 3H), 2.22 (m, 2H), 2.35 (m, 2H), 4.15 (q, 2H), 4.30 (t, 2H), 6.95 (d, 2H), 7.32-7.45 (m, 3H), 7.65 (s, 1H), 7.70 (d, 2H), 8.47 (m, 1H) ppm.

PREPARATIONS 2 to 4

The following compounds of the general formula:-

were prepared by hydrogenation of the corresponding benzyl ethers (see Examples 39 to 41) by similar methods to that used in Preparation 1.

PREPARATION 5

3-(4-Benzyloxybenzoyl) -1H-indole

A mechanically stirred solution of indole (30.0g) in sodium dried diethyl ether (450ml) was treated dropwise with methylmagnesium iodide (85ml of 3.0M solution in diethyl ether). After stirring for one hour at 20°C 4-benzyloxybenzoyl chloride (see Preparation 10) (67.3g) was added. Stirring was continued for two hours at 20°C and then 1N hydrochloric acid (250ml) added to the mixture and the reaction was allowed to stand overnight. The resulting precipitate was filtered off and triturated with hot ethyl acetate (3 x 100ml) to give the desired compound as a pale pink solid, (40.9g). Found: C,80.67; H, 5.33; N,4.25; C₂₂H₁₇NO₂ requires: C,80.70; H, 5.23;

N, 4.28%. 1H-NMR (d₆-DMSO) : δ = 5.20 (s, 2H), 7.15 (d, 2H), 7.20 (m, 2H), 7.30-7.50 (m, 6H), 7.80 (d, 2H), 7.90 (s, 1H), 8.23 (d, 1H), 11.95 (s,br, 1H) ppm. PREPARATIONS 6 to 8

The following indoles of the general formula:-

were prepared from the corresponding 1H-indoles and the corresponding acid chlorides (see Preparations 9 to 11) using similar methods to that used in Preparation 5.

PREPARATION 9

4-Benzyloxy-2,3-dimethylbenzoyl chloride

(a) 4-Bromo-2.3-dimethylohenol

A solution of 2,3-dimethylphenol (40.0g) in acetic acid (300ml) was cooled to 10°C and treated with a solution of bromine (16.9ml) in acetic acid (100ml). After stirring for 30 minutes saturated aqueous sodium metabisulphite solution (300ml) was added. The mixture was extracted with dichloromethane, the organic layer dried (MgSO₄), filtered and evaporated to provide the product as a waxy solid, (64.7g).

¹H-NMR (CDCl₃) : δ = 2.15 (s, 3H), 2.25 (s, 3H),

4. 00 (s, br, 1H) , 6. 60 (d, 1H) , 7. 15 (d, 1H) ppm.

Crystallisation of the product from hexane gave an analytical sample. Found: C,48.00; H,4.40; C₈H₉BrO requires: C,47.78; H,4.51%.

(b) 1-Benzyloxy-4-bromo-2,3-dimethylbenzene

A mixture of the product of part (a) (45.0g), benzyl bromide (28.30g), potassium carbonate (38.60g) and potassium iodide (300mg) in acetone (500ml) was heated at reflux overnight. The reaction was cooled, filtered and evaporated to give an oil which was dissolved in diethyl ether and washed with 2N aqueous sodium hydroxide solution. Evaporation of the organic layer gave an oil which was

chromatographed (silica, 4:1 hexane/ethyl acetate) to give the desired product, (51.86g). Found:

C, 62.64; H, 5.31; C₅₁H₁₅BrO requires: C, 61.85; H, 5.19%.

¹H-NMR (CDCl₃) : δ= 2.30 (s, 3H), 2.40 (s, 3H),

5.00 (s, 2H), 6.60 (d, 1H), 7.30-7.50 (m, 6H) ppm. (c) 4-Benzyloxy-2,3-dimethylbenzoic acid

A solution of the product of part (b) (33.8g) in tetrahydrofuran (THF) (500ml) at -78°C was treated with n-butyllithium (48.4ml of a 2.5M solution in hexane) . After stirring for 30 minutes at -78°C an excess of finely powdered solid carbon dioxide was added and the reaction allowed to warm to room temperature. The THF was removed in vacuo and the residue partitioned between ethyl acetate and 2N hydrochloric acid. The organic layer was washed with brine, dried (MgSO₄) and then evaporated to a pink solid. Recrystallisation from ethyl acetate gave the desired compound, (18.8g), m.p. 164-166°C. Found: C,74.87; H,6.21; C₁₆H₁₆O₃ requires: C,74.98; H,6.29%.

¹H-NMR (CDCl₃) : δ = 2.10 (s, 3H), 2.40 (s, 3H), 5.10 (s, 2H), 6.95 (d, 1H), 7.30-7.50 (m,5H), 7.60 (d, 1H) ppm.

(d) 4-Benzyloxy-2,3-dimethylbenzoyl chloride

The product of part (c) (2.0g) was suspended in dichloromethane (10ml) and treated with oxalyl chloride (1.3ml) and dimethylformamide (DMF) (2 drops). After stirring overnight the homogeneous solution was evaporated to give a white solid which was azeotroped three times with toluene to give the title compound as a white powder (2.24g). This material was used immediately.

PREPARATION 10

4-Benzyloxybenzoyl chloride

The title compound was prepared using a similar method to that described in Preparation 9 (d) except using

4-benzyloxybenzoic acid as the starting material. The material obtained was used immediately.

PREPARATION 11

4- (1-[4-Isobutylphenyl]ethoxy)benzoyl chloride

The title compound was prepared using a similar method to that described in Preparation 9 (d) except using 4-(1-[4-isobutylphenyl]ethoxy)benzoic acid (see

Preparation 28(b)) as the starting material. The product obtained was used immeddately.

PREPARATION 12

1-(4-n-Propylphenyl)butan-1-ol

A solution of 4-n-propylbenzaldehyde (7.4g) in diethyl ether (60ml) was cooled to 0°C and treated with a 2.0M solution of n-propylmagnesium chloride in diethyl ether (27.5ml). The reaction was stirred overnight, diluted with diethyl ether and quenched with saturated aqueous ammonium chloride solution. The organic layer was separated, washed with saturated aqueous ammonium chloride solution and dried (MgSO₄). The organic layer was filtered and evaporated to give a colourless oil which was purified by chromatography (silica, 4:1

hexane/ethyl acetate) to provide, after evaporation of the appropriate fractions, the desired product, (4.06g), m/z = 192 (M⁺).

¹Η-NMR (CDCl₃) : δ= 1.00 (m, 6H), 1.20-1.40 (m,2H),

1.70 (q, 2H), 1.75-1.90 (m, 3H), 2.60 (t, 2H), 4.60 (m, 1H), 7.10 (d, 2H), 7.30 (d, 2H) ppm.

PREPARATION 13

1-(4-Ethylphenyl)ethanol

A solution of 4-ethylacetophenone (10.0g) in

methanol (50ml) at 0°C was treated portionwise with sodium borohydride (3.83g). After stirring overnight at 20°C the reaction was partitioned between 1N hydrochloric acid and ethyl acetate. The organic layer was washed with 1N hydrochloric acid, dried (MgSO₄) and evaporated to give a clear oil (9.9g). This was purified by flash chromatography (silica, 3:1 hexane/ethyl acetate) to give, after evaporation of the appropriate fractions, the desired compound, (8.9g), m/z = 150 (M⁺). ¹H-NMR (CDCI₃) : δ = 1.25 (t,3H), 1.55 (d, 3H), 2.65 (q, 2H), 4.90 (q, 1H), 7.20 (d, 2H), 7.35 (d, 2H) ppm. PREPARATION 14

4-n-Propylbenzyl alcohol

A solution of 4-n-propylbromobenzene (log) in THF (100ml) at -78°C was treated with n-butyllithium (35ml of a 1.6M solution in hexane). After stirring for 15 minutes at this temperature paraformaldehyde (1.6g) was added and stirring continued for a further one hour. The reaction mixture was partitioned between diethyl ether and water, the organic layer was dried (MgSO₄) and evaporated to an oil. Flash chromatography (silica, 3:1 hexane/ethyl acetate) gave, after evaporation of the appropriate fractions, the desired product as a

colourless oil, (2.7g).

PREPARATION 15

(R,S)-1-(4-[2-Methylpropyl]phenyl)ethanol A solution of 4-isobutyrylacetophenone (10.0g) in methanol (50ml) was cooled to 0°C and treated portionwise with sodium borohydride (3.23g). After stirring

overnight at room temperature the reaction was quenched with 1N hydrochloric acid (50ml) and ethyl acetate

(100ml) added. The organic layer was separated, dried (MgSO₄) and evaporated to give the title compound as a clear oil, (10.02g), m/z = 178(M⁺). Found: C, 79.69;

H,9.90; C₁₂H₁₈O.1/7 H₂O requires: C,79.68; H,10.19%. 1H-NMR (CDCl₃) : δ= 0.90 (d, 6H), 1.50 (d, 3H), 1.85 (m, 1H), 2.50 (d, 2H), 4.85 (q, 1H), 7.15 (d, 2H), 7.30(d,2H) ppm.

PREPARATION 16

1-(3,4-Dichlorophenyl)ethanol

The title compound was prepared using a similar method to that described in Preparation 15 except using

3,4-dichloroacetophenone as the starting material, m/z =

190 (M⁺). ¹H-NMR (CDCl₃) : δ= 1.45(d,3H), 2.25 (s,br, 1H), 4.85(q,1H), 7.20(d,1H), 7.40(d,1H), 7.45(s,1H) ppm. PREPARATION 17

(R)-1-(4-[2-Methylpropyl]phenyl)ethanol

(a) Ethanoic acid (R,S)-1-(4-[2-methylpropyl]phenyl)- ethyl ester

A solution of the product of Preparation 15 (5.0g) in dichloromethane (40ml) at 0°C was treated with dry pyridine (2.5ml) followed by distilled acetyl chloride (2.2ml). After stirring overnight at room temperature the reaction mixture was filtered, silica (10g) added to the filtrate and the mixture evaporated to dryness. Column chromatography

(silica, 12:1 hexane/ethyl acetate) gave, after evaporation of the appropriate fractions, the desired compound as a clear oil, (2.3g). 1H-NMR (CDCl₃) : δ= 0.90(d,6H), 1.55(d,3H), 1.85(m,1H), 2.05(s,3H), 2.45(d,2H), 5.85(q,1H), 7.15(d,2H),

7.25(d,2H) ppm.

(b) (R) -1- (4-[2-Methylpropyl]phenyl)ethanol

A suspension of the product of part (a) (3.0g) in pH7 phosphate buffer (100ml) was treated with SAM II lipase (trade mark) (Fluka Chemicals Limited) (50mg) and the mixture stirred vigorously for 2 days at room temperature. The mixture was extracted with ethyl acetate (100ml), the combined organic layers dried (MgSO₄) and evaporated. Column chromatography (silica, 9:1 hexane/ethyl acetate) first gave, after combination and evaporation of the appropriate fractions, ethanoic acid (S)-1-(4-[2-methylpropyl]- phenylethyl ester, (1.47g). Further elution gave the title compound as a clear oil which crystallised to provide white needles, (1.04g), m.p. 37-38°C, [ α]_D + 32.3° (c = 2.7 in methanol).

¹Η-NMR (CDCI₃) : δ = 0.90(d,6H), 1.50(d,3H), 1.85(m,1H), 2.50(d,2H), 4.85(q,1H), 7.15(d,2H), 7.30(d,2H) ppm. PREPARATION 18

(S)-1-(4-[2-Methylpropyl]phenyl)ethanol

Ethanoic acid (S)-1-(4-[2-methylpropyl]phenylethyl ester (see Preparation 17(b)) (1.2g) was treated with a 1N solution of sodium hydroxide in absolute ethanol (20ml). After stirring overnight at room temperature the solvent was evaporated and the residue chromatographed (silica, 4:1 hexane/ethyl acetate) to give the title compound as a clear oil, (0.59g), m.p. 34°C, [α]_D - 32.7° (c = 2.7. in methanol). 1H-NMR (CDCl₃): δ= 0.90(d,6H), 1.50(d,3H), 1.85(m,1H) 2.50(d,2H), 4.85(q,1H), 7.15(d,2H), 7.30(d,2H) ppm.

PREPARATION 19

α-Cyclopentyl-4-n-propylbenzyl alcohol A solution of 4-n-propylbenzaldehyde (2.0g) in diethyl ether (20ml) was cooled to 0°C and treated with a solution of cyclopentylmagnesium chloride (7.4ml of a 2.0M solution in diethyl ether). After stirring at room temperature overnight the mixture was treated with saturated aqueous ammonium chloride solution. The organic layer was separated, dried (MgSO₄) and evaporated to provide a yellow oil. Flash chromatography (silica, initial elution with 4:1 hexane/ethyl acetate and then with 3:1 hexane/ethyl acetate) gave, after combination and evaporation of the appropriate fractions, the desired compound as a clear oil, (400mg), m/z = 218 (M⁺).

¹H-NMR (CDCI₃): δ= 1.00(t,3H), 1.00-1.60 (m, 10H),

2.25 (sextet, 1H), 2.60(m,2H), 4.40(d,2H), 7.30(d,2H), 7.40(d,2H) ppm. PREPARATIONS 20 to 26

The following alkyl bromides were prepared by dissolving the corresponding alcohol (see Preparations 12 to 16 and 19) in dichloromethane and cooling the solution in an ice-bath whilst saturating with dry hydrogen bromide. After stirring the mixture for a short period the reaction was evaporated in vacuo to provide the desired alkyl bromide which was used directly without characterisation.

1 For starting material see EP-A-291245.

PREPARATION 27

4-(3-[4-(1-Hydroxyethyl)benzoyl]indol-1-yl)butanoic acid ethyl ester

a) 3-(4-[1-(t-Butyldimethylsilyloxy)ethyl]- benzoyl)indole

The title compound was prepared by a similar method to that used in Preparation 5 using indole and 4-(1- [t-butyldimethyIsilyloxy]ethyl)benzoyl chloride as the starting materials, m/z = 380 (M+1)⁺. Found: C,72.79; H,7.73; N,3.76; C₂₃H₂₉NO₂Si requires:

C,72.78; H,7.70; N,3.69%.

¹H-NMR (CDCl₃): δ= 0.00 (s,3H), 0.40 (s,3H),

0.95 (s,9H), 1.45 (d, 3H), 4.95 (q,1H), 7.30-7.50 (m,5H), 7.70 (m, 1H), 7.80 (d,2H), 8.40 (m, 1H), 9.20 (s,br,1H) ppm. b) 4-(3-[4-(1-[t-Butyldimethylsilyloxy]ethyl)- benzoyl]indol-1-yl)butanoic acid ethyl ester

A solution of the product of part (a) (1.70g) in dimethylformamide (20ml) was treated with sodium hydride (215mg of a 60% dispersion in mineral oil). After stirring for 1 hour at room temperature ethyl 4-bromobutyrate (0.7ml) was added and stirring was continued for 2 hours. The reaction mixture was diluted with ethyl acetate (50ml) and washed

successively with 2N aqueous hydrochloric acid and saturated brine. The organic layer was dried (MgSO₄) and gave a yellow gum on evaporation of the solvent. Flash chromatography of this gum (silica, 3:1

hexane/ethyl acetate) followed by collection and evaporation of the appropriate fractions gave the title compound as a clear gum (2.20g), m/z =

494(M+1)⁺.

¹H-NMR (CDCI₃): δ= 0.00 (s, 6H), 0.90 (s, 9H),

1.20 (t, 3H), 1.50 (d, 3H), 2.20-2.40 (m, 4H), 4.10 (q, 2H), 4.30 (t, 2H), 5.00 (q, 1H), 7.20-7.40 (m, 5H), 7.60 (s, 1H), 7.80 (d, 2H), 8.35 (m, 1H) ppm. (c) 4-(3-[4-(1-Hydroxyethyl)benzoyl]indol-1-yl)butanoic acid ethyl ester

The product of part (b) was dissolved in

tetrahydrofuran (100ml) and treated with tetra-n- butylammonium fluoride (4.92g) and stirred for 1 hour. The reaction mixture was diluted with ethyl acetate (100ml) and washed with 2N aqueous

hydrochloric acid and saturated brine. The organic layer was dried (MgSO₄), filtered and evaporated to a brown gum. Flash chromatography (silica, 98:2 dichloromethane/methanol) gave, after collection and evaporation of the appropriate fractions, the title compound (0.92g) as a clear gum, m/z = 380 (M+1)⁺.

¹H-NMR (CDCl₃): δ= 1.20(t,3H), 1.70(d,3H),

2.00(s,br,1H), 2.20-2.40(m,4H), 4.10(q,2H),

4.30(t,2H), 5.00(q,1H), 7.20-7.60 (m,6H), 7.80(d,2H), 8.35(m,1H) ppm.

PREPARATION 28

(S)-4-(3-[4-(1-[4-(2-Methylpropyl)phenyl]lethoxy)- benzoyl]indol-1-yl)butanoic acid

(a) (R,S)-4-(1-[4-(2-Methylpropyl)phenyl]ethoxy)benzoic acid ethyl ester

Ethyl p-hydroxybenzoate (5.16g) was dissolved in acetone (50ml) and treated with anhydrous potassium carbonate (4.40g), tetra-n-butylammonium bromide (0.44g) and (R,S)-α-methyl-4-(2-methylpropyl) benzyl bromide (see Preparation 23) (7.7g). The resultant slurry was stirred overnight at room temperature and filtered. The filtrate was evaporated to give the title compound (13.5g) which was used directly without characterisation. (b) (R,S)-4-(1-[4-(2-Methylpropyl)phenyl)ethoxy)benzoic acid

The product of part (a) (13.5g) was dissolved in 95% aqueous ethanol (108ml), treated with 2N aqueous sodium hydroxide (32ml) and heated at 60-70°C for 90 minutes. The solvent was evaporated and water

(30ml) added. The mixture was treated with 2N aqueous hydrochloric acid (50ml) and then extracted with ethyl acetate. The combined organic layers were washed with saturated brine and dried (MgSO₄). Removal of the ethyl acetate solvent gave the title compound as a white solid. Trituration with n- hexane gave a fine white powder (6.7g).

¹Η-NMR (CDCl₃): δ= 0.95(d,6H), 1.70(d,3H),

1.88(m,1H), 2.51(d,2H), 5.40(q,1H), 6.95(d,2H), 7.17(d,2H), 7.30(d,2H), 8.00(d,2H) ppm.

(c) (S)-4-(1-[4-(2-Methylpropyl)phenyl]ethoxy)benzoic acid, (+)-ephedrine salt

The product of part (b) (10g) was dissolved in 95% aqueous ethanol (60ml) and water (60ml) and treated with (+)-ephedrine hemihydrate (5.84g). The mixture was heated under reflux until complete solution was achieved. The reaction was allowed to stand at room temperature overnight. The resulting precipitate was removed by filtration and dried to provide the title compound (5.20g).

-21.9° (c=1 in methanol).

¹H-NMR (CDCI₃) : δ= 0.90(d,6H), 1.10(d,3H),

1.70(d,3H), 1.85(m,1H), 2.45(S,3H), 3.15(m,1H), 5.45(m,2H), 6.88(d,2H), 7.10(d,2H), 7.30(m,7H), 7.90(m,2H) ppm.

Chiral HPLC analysis of the product showed it to contain a 95:5 ratio of the (S) : (R) enantiomers.

(d) (S)-4-(1-[4-(2-Methylpropyl)phenyl]ethoxy)benzoic acid

The product of part (c) (4.63g) was treated with 1N aqueous hydrochloric acid and the resultant slurry stirred for 90 minutes. The resultant precipitate was filtered off and washed with 1N aqueous

hydrochloric acid then water. The product was dried in vacuo at 50°C to give the desired compound as a colourless solid, (2.94g), m.p. 128-131°C.

-51.5° (c=1 in methanol).

Found: C,76.76; H,7.30; N,0.00; C₁₉H₂₂O₃ requires: C,76.48; H,7.43; N,0.00%.

¹H-NMR (CDCI₃) : δ= 0.95(d,6H) , 1.70(d,3H),

1.88(m,1H) , 2.51(d,2H), 5.40(q,1H), 6.95(d,2H), 7.17(d,2H), 7.30(d,2H), 8.00(d,2H) ppm.

(e) (S)-4-(1-[4-(2-Methylpropyl)phenyl]ethoxy)benzoyl chloride

The product of part (d) (2g) was dissolved in dichloromethane (10ml) and treated with pyridine (0.60ml) followed by oxalyl chloride (0.64ml). The mixture was stirred for 3 hours at room temperature, one drop of dimethylformamide was added and the mixture stirred overnight. The solvent was removed by evaporation and dry toluene (40ml) added. The resultant precipitate was removed by filtration and the filtrate containing the title compound was evaporated to a volume of 10ml and used directly in the next step without characterisation.

(f) (S)-3-(4-[1-(4-[2-Methylpropyl]phenyl)- ethoxy]benzoyl)indole

Indole (715mg) was dissolved in toluene (5ml) and treated with methylmagnesium iodide (2.0ml of a 3M solution in diethyl ether). The resultant yellow solution was stirred for 10 minutes and a solution of (S)-4-(1-[4-(2-methyIpropyl)phenyl]ethoxy)benzoyl chloride in toluene (10ml) (the product of part (e)) was added. The mixture was stirred at room

temperature for 1 hour and then a saturated solution of aqueous ammonium chloride (50ml) was added with vigorous stirring. The mixture was extracted with ethyl acetate (30ml, 40ml and 15ml) and the combined organic layers were dried (MgSO₄), filtered and evaporated to give a brown gum. Flash

chromatography (silica, 3:1 hexane/ethyl acetate initially, followed by 1:1 hexane/ethyl acetate) gave, after evaporation of the appropriate

fractions, the title compound as a beige solid

(1.05g), m.p. 150-152°C. Found: C,81.69; H,6.83; N,3.58; C₂₇H₂₇NO₂ requires: C,81.58; H,6.85; N,3.52%.

¹Η-NMR (CDCl₃): δ= 1.00(d,6H), 1.75(d,3H),

1.95(m,1H), 2.55(d,2H), 5.45(q,1H), 7.05(d,2H), 7.25(d,2H) 7.39-7.54(m,4H), 7.70(m,1H), 7.85(d,2H), 8.45(m,1H), 9.10 (s,br,1H) ppm. (g) (S) -4- (3- [ 4- ( 1- [ 4- ( 2-Methylpropyl) pheny l]- ethoxy)benzoyl]indol-1-yl)butanoic acid ethyl ester A solution of the product of part (f) (500mg) in 2- butanone (5ml) was treated with anhydrous potassium carbonate (695mg) and ethyl 4-bromobutyrate

(0.23ml). The mixture was heated under reflux overnight, cooled, filtered and the filtrate evaporated to a yellow gum. Flash chromatography (silica, 3:1 hexane/ethyl acetate) gave, after collection and evaporation of the appropriate fractions, the title compound (451mg).

This product had identical mass spectroscopy,

H.P.L.C. and ¹H-NMR characteristics to the compound of Example 33.

(h) (S)-4-(3-[4-(1-[4-(2-Methylpropyl)phenyl]- ethoxy)benzoyl]indol-1-yl)butanoic acid

A solution of the product of part (g) (108mg) in 95% aqueous ethanol (2ml) was treated with six drops of 2N aqueous sodium hydroxide. The mixture was stirred for 90 minutes then water (3ml) was added followed by 2N aqueous hydrochloric acid until the mixture reached pH1. The mixture was extracted with dichloromethane (3 x 10ml) and the combined organic layers were evaporated to give the title compound as a colourless foam (62mg).

This product had identical mass spectroscopy, optical rotation and ¹H-NMR characteristics to the compound of Example 9. Pharmacological activity

A selection of compounds of the formula (I) was tested in vitro for steroid 5α-reductase inhibitory activity using ventral prostate tissue from male rats according to the procedure outlined on pages 34 to 36 of the specification. The results are presented in Table 1.

Toxicity

The compound of Example 1 was administered orally to mice up to dose of 1000mg/kg and the animal showed normal appearance and behaviour throughout the duration of the study.

Claims

1. A compound of the formula:-

or a pharmaceutically acceptable salt thereof, wherein

Y is C₁-C₈ alkylene optionally substituted by

C₁-C₆ alkyl;

R is H, OH, halo, C₁-C₄ alkyl or C₁-C₄ alkoxy;

R¹, R², R³ and R⁴ are each independently selected from H, C₁-C₄ alkyl, C₁-C₄ alkoxy, OH, halo and CF₃; one of R⁶, R⁷ and R⁸ is a group of the formula: -

R¹¹ is a biolabile ester-forming group;

R¹² and R¹³ are each independently selected from H and C₁-C₄ alkyl;

R¹⁴ is H, C₁-C₆ alkyl, C₃-C₇ cycloalkyl or aryl; and "aryl", used in the definitions of R⁶, R⁷, R⁸ and R¹⁴, means phenyl optionally substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, C₂-C₆ alkenyl, OH, halo, CF₃, halo(C₁-C₆ alkyl), nitro, amino, C₂-C₆ alkanamido, C₂-C₆ alkanoyl or phenyl.

2. A compound as claimed in claim 1 wherein

Y is C₁-C₆ alkylene optionally substituted by C₁-C₆ alkyl;

R is H, OH, halo, C₁-C₄ alkyl or C₁-C₄ alkoxy;

-OCH-Aryl or -CHO-Aryl, and the remainder, together with R⁵ and R⁹, are each independently selected from H, C₁-C₄ alkyl, C₁-C₄ alkoxy, halo and halo ( C₁-C₄)alkyl;

R¹² and R¹³ are each independently selected from H and C₁-C₄ alkyl;

R¹⁴ is H, C₁-C₆ alkyl , C₃-C₇ cycloalkyl or aryl; and "aryl" , used in the definitions of R⁶, R⁷, R⁸ and R¹⁴, means phenyl optionally substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, C₂-C₆ alkenyl, OH, halo , CF₃, halo (C₁-C₆ alkyl) , nitro, amino, C₂-C₆ alkanamido , C₂-C₅ alkanoyl or phenyl: with the provisos

i) when R⁷ is 1- (4- (2-methylpropyl) - phenyl) ethoxy, R, R¹, R², R³, R⁴, R⁵, R⁶, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH when the compound of the formula (I) is in the racemic form;

ii) when R⁷ is 1-(4-(2-methylpropyl)- phenyl) propoxy or 2,2-dimethyl-1-(4-(2- methylpropyl)phenyl)propoxy, R, R¹, R², R³, R⁴, R⁵, R⁶, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH or COOC₂H₅ when the compound of the formula (I) is in the racemic form;

iii) when R⁶ is 1-(3-(2-methyIpropyl)phenyl)- ethoxy, R, R¹, R^z, R³, R⁴, R⁵, R⁷, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH or COOC₂H₅ when the compound of the formula (I) is in the racemic form; iv) when R⁷ is 1-(4-(2-methylpropyl)phenyl)- ethoxy, R⁵ and R⁶ are both methyl, R, R¹, R², R³, R⁴, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH or COOC₂H₅ when the compound of the formula (I) is in the racemic form;

v) when R⁷ is bis (4-(2-methylpropyl)phenyl)- methoxy, R, R¹, R², R³, R⁴, R⁵, R⁶, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH;

vi) when R⁶ is bis (4-(2-methyIpropyl)phenyl)- methoxy, R, R¹, R², R³, R⁴, R⁵, R⁷, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH; and

vii) when R⁶ is 4-(2-methylpropyl)phenoxymethyl or 3-(2-methylpropyl)phenoxymethyl, R, R¹, R², R³, R⁴, R⁵, R⁷, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH or COOC₂H₅.

3. A compound as claimed in claim 1 or 2 wherein R¹⁰ is COOH or COOR¹¹.

4. A compound as claimed in any preceding claim wherein R¹¹ is C₁-C₆ alkyl.

5. A compound as claimed in any preceding claim wherein R¹⁰ is COOH.

6. A compound as claimed in any preceding claim wherein

Y is C₁-C₆ alkylene;

R is H or C₁-C₄ alkyl ;

R¹ , R² , R³ and R⁴ are each H;

one of R⁶ , R⁷ and R⁸ is a group of the formula : - -O

CH-Aryl or -CHO-Aryl, and the remainder, together with R⁵ and R⁹, are each independently selected from H and C₁-C₄ alkyl;

R¹⁴ is H, C₁-C₄ alkyl, C₄-C₆ cycloalkyl or phenyl substituted by C₁-C₄ alkyl; and "aryl", when used in the definitions of R⁶, R⁷ and R⁸, means phenyl optionally substituted by from 1 to 3 substituents each independently selected from C₁-C₆ alkyl and halo.

7. A compound as claimed in claim 6 wherein

Y is methylene, propylene, butylene or

pentylene;

R is H or methyl;

R⁷ is a group of the formula:-

-O

CH-Aryl or -

CHO-Aryl, and R⁵, R⁵, R⁸ and R⁹ are each independently selected from H and C₁-C₄ alkyl;

R¹⁴ is H, methyl, n-propyl, cyclopentyl or

4-(n-propyl) phenyl; and

"aryl" means phenyl optionally substituted by 1 or 2 substituents each independently selected from methyl, ethyl, n-propyl, isobutyl and chloro.

8. A compound as claimed in claim 7 wherein

Y is propylene;

R is H;

R⁷ is a group of the formula: -

-OCH-Aryl,

and R⁵, R⁶, R⁸ and R⁹ are each H; R¹⁴ is methyl; and

"aryl" means phenyl, 4-methylphenyl, 4-ethylphenyl, 4- (n-propyl) phenyl, 4-isobutylphenyl or 3,4- dichlorophenyl.

9. A compound as claimed in claim 8 wherein "aryl"

means 4-isobutylphenyl.

10. A compound as claimed in claim 1 or 2 wherein one of R⁶, R⁷ and R⁸ is a group of the formula:-

and the remainder, together with Y, R, R¹, R², R³, R⁴, R⁵, R⁹, R¹⁰, R¹¹, R¹², R¹³ and "aryl", are as defined in claim 1 or 2.

11. (R,S)-4-(3-[4-(1-[4-(2-Methylpropyl)phenyl]ethoxy)- benzoyl]indol-1-yl) butanoic acid,

(S)-4-(3-[4-(l-[4-(2-Methylpropyl)phenyl]ethoxy)- benzoyl]indol-1-yl) butanoic acid,

(R,S)-4-(2-Methyl-3-[4-(1-[4-(2-methylpropyl)- phenyl]ethoxy)benzoyl]indol-1-yl) butanoic acid or (S)-4-(2-Methyl-3-[4-(1-[4-(2-methylpropyl)phenyl]- ethoxy)benzoyl]indol-1-yl) butanoic acid: or a

pharmaceutically acceptable salt thereof.

12. A pharmaceutical composition comprising a compound of the formula (I), or a pharmaceutically acceptable salt thereof, as claimed in any one of the preceding claims, together with a pharmaceutically acceptable diluent or carrier.

13. A compound of the formula (I), or a pharmaceutically acceptable salt or composition thereof, as claimed in any one of claims 1 to 11 and 12 respectively, for use as a medicament.

14. The use of a compound of the formula (I), or of a pharmaceutically acceptable salt or composition thereof, as claimed in any one of claims 1 to 11 and 12 respectively, for the manufacture of a medicament for inhibiting a steroid 5α-reductase.

15. The use of a compound of the formula (I), or of a pharmaceutically acceptable salt or composition thereof, as claimed in any one of claims 1 to 11 and 12 respectively, for the manufacture of a medicament for the curative or prophylactic treatment of acne vulgaris, alopecia, seborrhoea, female hirsutism, benign prostatic hypertrophy or male pattern

baldness.

16. The use of a compound of the formula (I), or of a pharmaceutically acceptable salt or composition thereof, as claimed in any one of claims 1 to 11 and 12 respectively, for the manufacture of a medicament for the curative or prophylactic treatment of a human prostate adenocarcinoma.

17. A method of treatment of a human to inhibit a steroid 5α-reductase which comprises treating said human with an effective amount of a compound of the formula (I) or with a pharmaceutically acceptable salt or composition thereof as claimed in any one of claims 1 to 11 and 12 respectively.

18. A method of treatment of a human to cure or prevent acne vulgaris, alopecia, seborrhoea, female

hirsutism, benign prostatic hypertrophy, male pattern baldness or a human prostate adenocarcinoma which comprises treating said human with an

effective amount of a compound of the formula (I) or with a pharmaceutically acceptable salt or

composition thereof as claimed in any one of claims 1 to 11 and 12 respectively.

19. A compound of the formula:-

or a base salt thereof;

or a base salt thereof;

or a base salt thereof;

or a base salt thereof; or

wherein Y, R, R¹, R², R³, R⁴, R⁵ , R⁶, R⁷ , R⁸, R⁹ and R¹⁰ are as defined in claim 1 or 2 ; R²⁴ is H or OH; one of R²⁵, R²⁶ and R²⁷ is OH and the remainder of R²⁵, R²⁶ and R²⁷ are as defined in claim 1 or 2 for the remainder of R⁶, R⁷ and R⁸; one of R²⁸, R²⁹ and R³⁰ is a group of the formula: -

-CH-Z⁸

wherein R¹⁴ is as defined in claim 1 or 2 and Z⁸ is a leaving group, and the remainder of R²⁸, R²⁹ and R³⁰ are as defined in claim 1 or 2 for the remainder of

R⁶, R⁷ and R⁸; and one of R³¹, R³² and R³³ is a group of the formula:-

-CH-OH

wherein R¹⁴ is as defined in claim 1 or 2,

and the remainder of R³¹, R³² and R³³ are as defined in claim l or 2 for the remainder of R⁶, R⁷ and R⁸.

20. A compound of the formula (XXI) or a base salt

thereof as claimed in claim 19 wherein Z⁸ is halo, C₁-C₄ alkanesulphonyloxy or C₁-C₄

alkylphenylsulphonyloxy.

21. A process for the preparation of a compound of the formula:-

or a pharmaceutically acceptable salt thereof,

wherein Y is C₁-C₆ alkylene optionally substituted by

C₁-C₆ alkyl;

R is H, OH, halo, C₁-C₄ alkyl or C₁-C₄ alkoxy;

R¹¹ is a biolabile ester-forming group;

R¹² and R¹³ are each independently selected from H and C₁-C₄ alkyl;

R¹⁴ is H, C₁-C₆ alkyl, C₃-C₇ cycloalkyl or aryl; and "aryl", used in the definitions of R⁶, R⁷, R⁸ and R¹⁴, means phenyl optionally substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, C₂-C₆ alkenyl, OH, halo, CF₃, halo(C₁-C₆ alkyl), nitro, amino, C₂-C₆ alkanamido, C₂-C₆ alkanoyl or phenyl, which comprises,

(a) for the preparation of a compound of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I), cleavage of an ester of the formula:-

wherein R¹⁵ is an ester-forming group that may be cleaved to provide a compound of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I); (b) for the preparation of a compound of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I), acidic or basic hydrolysis of a compound of the formula (I) wherein R¹⁰ is CONR¹²R¹³ and Y, R, R¹ to R⁹, R¹² and R¹³ are as previously defined for a compound of the formula (I);

(c) for the preparation of a compound of the

formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I), acidic or basic hydrolysis of a compound of the formula:-

wherein Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I);

(d) for the preparation of a compound of the

formula (I) wherein R¹⁰ is COOR ¹¹ and Y, R, R¹ to

R⁹ and R¹¹ are as previously defined for a compound of the formula (I), esterification of a compound of the formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I) , with an alcohol of the formula R¹¹OH wherein R¹¹ is as previously defined for a compound of the formula (I);

(e) for the preparation of a compound of the

formula (I) wherein Y, R and R¹ to R¹⁰ are as previously defined for a compound of the formula (I), alkylation of a base salt of a compound of the formula:-

wherein R and R¹ to R⁹ are as previously defined for a compound of the formula (I), with a compound of the formula Z³-Y-COOR¹¹ or

Z³-Y-CONR¹²R¹³ or with a base salt of a compound of the formula Z³-Y-COOH, wherein Y, R¹¹, R¹² and

R¹³ are as previously defined for a compound of the formula (I) and Z³ is a leaving group;

(f) for the preparation of a compound of the

formula (I) wherein R¹⁰ is COOH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I), oxidation of a compound of the formula:-

(g) for the preparation of a compound of the

or a base salt thereof, wherein R²⁴ is H or OH and Y, R and R¹ to R⁹ are as previously defined for a compound of the formula (I);

(h) for the preparation of a compound of the

formula (I) wherein one of R⁶, R⁷ and R⁸ is a group of the formula:- -

OCH-Aryl

and the remainder of R⁶, R⁷ and R⁸,

together with Y, R, R¹ to R⁵, R⁹, R¹⁰, R¹⁴ and "aryl" are as previously defined for a compound of the formula (I), reaction of a compound of the formula:-

or a base salt thereof, wherein one of R²⁵, R²⁶ and R²⁷ is OH and the remainder of R²⁵, R²⁶ and R²⁷ are as previously defined for the remainder of R⁶, R⁷ and R⁸ for a compound of the formula (I), and Y, R, R¹ to R⁵,

R⁹ and R¹⁰ are as previously defined for a compound of the formula (I), with a compound of the formula:-

Z⁷-CH-Aryl ....(XIX) wherein R¹⁴ and "aryl" are as previously defined for a compound of the formula (I) and Z⁷ is a leaving group;

(i) for the preparation of a compound of the

formula (I) wherein R¹⁰ is COOR¹¹ or CONR¹²R¹³, one of R⁶, R⁷ and R⁸ is a group of the formula:-

-OCH-Aryl

and the remainder of R⁶, R⁷ and R⁸, together with Y, R, R¹ to R⁵, R⁹, R¹¹, R¹², R¹³, R¹⁴ and

"aryl" are as previously defined for a compound of the formula (I), reaction of a compound of the formula (XVIII) wherein R¹⁰ is COOR¹¹ or

CONR¹²R¹³, Y, R, R¹ to R⁵, R⁹, R¹¹, R¹² and R¹³ are as previously defined for a compound of the formula (I) and R²⁵, R²⁶ and R²⁷ are as defined in claim 21(h), with a compound of the formula:-

HO-CH-Aryl ....(XX) wherein R¹⁴ and "aryl" are as previously defined for a compound of the formula (I), in the presence of a dehydrating agent; (j) for the preparation of a compound of the formula (I) wherein one of R⁶, R⁷ and R⁸ is a group of the formula:-

-CHO-Aryl,

and the remainder of R⁶, R⁷ and R⁸, together with Y, R, R¹ to R⁵, R⁹, R¹⁰, R¹⁴ and "aryl" are as previously defined for a compound of the formula (I), reaction of a compound of the formula:-

-CH-Z⁸

and the remainder of R²⁸, R²⁹ and R³⁰ are as previously defined for the remainder of R⁶, R⁷ and R⁸ for a compound of the formula (I), Y, R, R¹ to R⁵, R⁹, R¹⁰ and R¹⁴ are as previously defined for a compound of the formula (I) and Z⁸ is a leaving group, with a base salt of a compound of the formula:- Aryl-OH ..... (XXII) wherein "aryl" is as previously defined for a compound of the formula (I); or

(k) for the preparation of a compound of the

-

CHO-Aryl,

and the remainder of R⁶, R⁷ and R⁸, together with Y, R, R¹ to R⁵, R⁹, R¹¹, R¹², R¹³, R¹⁴ and "aryl" are as previously defined for a compound of the formula (I), reaction of a compound of the formula:-

wherein one of R³¹ , R³² and R³³ is a group of the formula : -

-CH-OH

and the remainder are as previously defined for the remainder of R⁶ , R⁷ and R⁸ for a compound of the formula ( I) , R¹⁰ is COOR¹¹ or CONR¹²R¹³ and Y ,

R, R¹ to R⁵ , R⁹, R¹¹ , R^1Z , R¹³ and R¹⁴ are as previously defined for a compound of the formula (I), with a compound of the formula (XXII) wherein "aryl" is as previously defined for a compound of the formula (I), in the presence of a dehydrating agent: any one of said processes (a) to (k) being optionally followed by

conversion of the product of the formula (I) to a pharmaceutically acceptable salt thereof.

22. A process as claimed in claim 21 wherein

Y is C₁-C₆ alkylene optionally substituted by C₁-C₆ alkyl;

R is H, OH, halo, C₁-C₄ alkyl or C₁-C₄ alkoxy;

-OCH-Aryl or -CHO-Aryl, and the remainder, together with R⁵ and R⁹, are each independently selected from H, C₁-C₄ alkyl,

C₁-C₄ alkoxy, halo and halo (C₁-C₄) alkyl;

R¹⁰ is COOH, COOR¹¹ or CONR¹²R¹³;

R¹¹ is a biolabile ester-forming group;

R¹² and R¹³ are each independently selected from H and C₁-C₄ alkyl ;

R¹⁴ is H, C₁-C₆ alkyl, C₃-C₇ cycloalkyl or aryl; and "aryl" , used in the definitions of R⁶, R⁷ , R⁸ and R¹⁴ , means phenyl optionally substituted by C₁-C₆ alkyl , C₁-C₆ alkoxy, C₂-C₆ alkenyl , OH, halo , CF₃ , halo (C₁-C₆ alkyl) , nitro, amino, C₂-C₆ alkanamido , C₂-C₆ alkanoyl or phenyl : with the provisos

i) when R⁷ is 1-(4-(2-methylpropyl)- phenyl) ethoxy, R, R¹, R², R³, R⁴, R⁵, R⁶, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH when the compound of the formula (I) is in the racemic form;

ii) when R⁷ is 1-(4-(2-methylpropyl)- phenyl) propoxy or 2,2-dimethyl-1-(4-(2- methylpropyl) phenyl) propoxy, R, R¹, R², R³, R⁴, R⁵, R⁶, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH or COOC₂H₅ when the compound of the formula (I) is in the racemic form;

iii) when R⁶ is 1-(3-(2-methyIpropyl)phenyl)- ethoxy, R, R¹, R², R³, R⁴, R⁵, R⁷, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH or COOC₂H₅ when the compound of the formula (I) is in the racemic form;

iv) when R⁷ is 1-(4-(2-methylpropyl)phenyl)- ethoxy, R⁵ and R⁶ are both methyl, R, R¹, R², R³, R⁴, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH or COOC₂H₅ when the compound of the formula (I) is in the racemic form;

v) when R⁷ is bis (4-(2-methyIpropyl)phenyl)- methoxy, R, R¹, R², R³, R⁴, R⁵, R⁶, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH; vi) when R⁵ is bis (4-(2-methylpropyl)phenyl)- methoxy, R, R¹, R², R³, R⁴, R⁵, R⁷, R⁸ and R⁹ are all H and Y is -(CH₂)₃-, that R¹⁰ is not COOH; and

23. A process as claimed in claim 21(a) or 22 where the cleavage is carried out by acidic or basic

hydrolysis of a compound of the formula (II).

24. A process as claimed in claim 21(a), 22 or 23

wherein R¹⁵ is C₁-C₆ alkyl.

25. A process as claimed in claim 23 or 24 where the

cleavage is carried out by basic hydrolysis using sodium or potassium hydroxide under aqueous

conditions.

26. A process as claimed in claim 21(e) or 22 where the base salt of a compound of the formula (VIII) is a sodium or potassium salt.

27. A process as claimed in claim 21(e), 22 or 26

wherein Z³ is halo, C₁-C₄ alkanesulphonyloxy or C₁-C₄ alkylphenylsulphonyloxy.

28. A process as claimed in claim 27 wherein Z³ is bromo.

29. A process as claimed in claim 21(h) or 22 where a base salt of a compound of the formula (XVIII) is used.

30. A process as claimed in claim 29 where the base salt is a sodium or potassium salt.

31. A process as claimed in claim 21(h), 22, 29 or 30

wherein Z⁷ is halo, C₁-C₄ alkanesulphonyloxy or

C₁-C₄ alkylphenylsulphonyloxy.

32. A process as claimed in claim 31 wherein Z⁷ is bromo.

33. A process as claimed in claim 21(i), 21(k) or 22

where the dehydrating agent used is a combination. of diethyl azodicarboxylate and triphenylphosphine.

34. A process as claimed in claim 21 (j) or 22 wherein Z⁸ is halo, C₁-C₄ alkanesulphonyloxy or C₁-C₄

alkylphenylsulphonyloxy.

35. A process as claimed in any one of claims 21 to 34 wherein R¹⁰ is COOH or COOR¹¹.

36. A process as claimed in claim 35 wherein R¹¹ is C₁-C₆ alkyl.

37. A process as claimed in any one of claims 21 to 32 or 34 wherein R¹⁰ is COOH.

38. A process as claimed in any one of claims 21 to 37 wherein

Y is C₁-C₆ alkylene;

R is H or C₁-C₄ alkyl;

R¹, R², R³ and R⁴ are each H;

one of R⁶, R⁷ and R⁸ is a group of the formula:-

-OCH-Aryl or -CHO-Aryl, and the remainder, together with R⁵ and R⁹, are each independently selected from H and C₁-C₄ alkyl;

R¹⁴ is H, C₁-C₄ alkyl, C₄-C₆ cycloalkyl or phenyl substituted by C₁-C₄ alkyl; and

"aryl", when used in the definitions of R⁶, R⁷ and R⁸, means phenyl optionally substituted by from 1 to 3 substituents each independently selected from C₁-C₆ alkyl and halo.

39. A process as claimed in claim 38 wherein

Y is methylene, propylene, butylene or pentylene;

R is H or methyl;

R⁷ is a group of the formula:-

-O

CH-Aryl or -CHO-Aryl, and R⁵, R⁵, R⁸ and R⁹ are each independently selected from H and C₁-C₄ alkyl;

R¹⁴ is H, methyl, n-propyl, cyclopentyl or

4-(n-propyl)phenyl; and

40. A process as claimed in any one of claims 21 to 33 or 35 to 37 wherein

Y is propylene;

R is H;

R¹, R², R³ and R⁴ are each H;

R⁷ is a group of the formula : - -O

CH-Aryl ,

and R⁵, R⁶, R⁸ and R⁹ are each H;

R¹⁴ is methyl; and

"aryl" means phenyl, 4-methylphenyl,

4-ethylphenyl, 4-(n-propyl)phenyl,

4-isobutylphenyl or 3,4-dichlorophenyl.

41. A process as claimed in any one of claims 21 to 40 wherein "aryl" means 4-isobutylphenyl.

42. A process as claimed in claim 21 or 22 which is used to prepare a compound of the formula (I) wherein one of R⁶, R⁷ and R⁸ is a group of the formula:-

and the remainder, together with Y, R, R¹, R², R³, R⁴, R⁵, R⁹, R¹⁰, R¹¹, R¹², R¹³ and "aryl", are as defined in claim 21 or 22.

43. A process as claimed in claim 21 or 22, in part, which is used to prepare

(R,S)-4-(3-[4-(1-[4-(2-Methylpropyl)phenyl]ethoxy)- benzoyl] indol-1-yl)butanoic acid,

(R,S) -4-(2-Methyl-3-[4-(1-[4-(2-methylpropyl)- phenyl]ethoxy)benzoyl]indol-1-yl) butanoic acid or (S)-4-(2-Methyl-3-[4-(1-[4-(2-methylpropyl)phenyl]- ethoxy)benzoyl]indol-1-yl) butanoic acid: or

a pharmaceutically acceptable salt thereof.

44. A process for the preparation of a pharmaceutical composition which comprises combining a compound of the formula (I), or a pharmaceutically acceptable salt thereof, which has been prepared by a process as claimed in any one of claims 21 to 43, together with a pharmaceutically acceptable diluent or carrier.