CA1069498A

CA1069498A - Pharmaceutically active steroids

Info

Publication number: CA1069498A
Application number: CA248,260A
Authority: CA
Inventors: Frederick Cassidy
Original assignee: Beecham Group PLC
Current assignee: Beecham Group PLC
Priority date: 1975-03-21
Filing date: 1976-03-19
Publication date: 1980-01-08
Also published as: CH621560A5; IL49132A; SE7603410L; FR2304345A1; GB1538227A; BE839751A; DK123476A; AT357700B; NL184111C; FR2445340B1; DE2610497C2; DK143757C; DK143757B; FR2304345B1; ZA761324B; AU501246B2; FR2445340A1; AU1220776A; IE42308L; IL49132A0

Abstract

ABSTRACT OF THE DISCLOSURE

Compounds of the formula (I) are provided:

(I) wherein:
R3 is a C1-5 alkyl group, a C3-6 alkenyl group, a C3-6 cycloalkyl group or an alkylphenyl group in which the alkyl moiety is optionally sub-stituted; R4 is a hydroxyl group, or a group OR6 wherein R6 is a C2-7 acyl group, a C1-4 alkyl group, or an optionally substituted benzyl group; R5 is hydrogen or a C1-5 alkyl group; or R4 and R5 together with the carbon atom to which they are joined represent a carbonyl group. These compounds are use-ful in the treatment of androgen dependent skin disorders, such as acne.

Description

This invention relates to novel compounds having pharmaceutical activity, to pharmaceutical compositions containing t~em and to a method for their use. ~ process for the preparation of these novel compounds is also provided, as are novel intermediates useful in that process.
More specifially this inven~ivn relates to novel steroids useful in the treatment of androgen dependent skin disorders.
Many skin conditions, such as acne and seborrhoea, are thought to arise because of excessive secretion of sebum from the sebaceous glands under ~`
androgenic stimulation. It is now believe that testosterone, the principal circulating androgen, is converted to 5~i-dihydrotestosterone (DHT) at androgen target cells, and therefore that it is D~T that is the biologically active androgen causing this stimulation. The enzyme responsible for this conversion is ~ - 3-ketosteroid-5~-reductase. Thus it will be realized that a compound capable of inhibiting the effect of this enzyme on circulating testosterone, or having anti-androgenic activity by virtue of its ability to compete with DHT for target sites, will be of use in the treatment of the aforesaid skin conditions.
It has now been discovered that certain novel androstenes related to testosterone, but di-substituted in the 16 position by certain hydrocarbon -groups, have 5~ reductase inhibitory activity, and that the corresponding an-drostanes are weak anti-androgens by virtue of their ability to compete with DHT for target sites. The androstenes also possess a very weak anti-androgenicity of this competitive nature. These steroids are therefore useful in the treatment of the aforesaid skin conditions, such as acne and seborrhoea. It is believed that treatment of other androgen dependent disorders associated with the skin and hair follicles such as female hirsutism, androgenic alopecia and male pattern baldness in women is also possible with these steroids.
It is known (W. Voigt and S.L. Hsia, Endrocrinology, 1973~ 92, 1216-1222) that 4-androsten-3-one-17 -carboxylic acid, of formula ~) below, and its methyl ester have 5~,reductase inhibitory activity:
~ ~ ~00~1 ,/J~,,J (A) ~ O ~ ' ~

However these two compounds are structurally less closely related to the androstenes of the invention than is testosterone, the standard reference androgen.
It is also known from US Patent No: 3853926 that 17~-hydroxy-16,16-dimethyl estr-4-en-3-one, of forumula (B) below, is an anti androgen and has the capacity to suppress the secretion of sebum in rats: !

OH

O

This steroid is an estrene, while the unsaturated steroids of the invention are androstenes. The fact that l9-nor-test-osterone, an estrene, and most derivatives !
thereof are gestgens and testosterone, an androstene, is an androgen, clearly ;;

shows that no prediction as to pharmaceutical activity can safely be made from the one class of steroid to the other.
Accordingly the present invention provides compounds of the formula ~ 3 wherein: ¦
R3 is a Cl 5 alkyl group,~ a C3 6 alkenyl group, a C3 6 cycloalkyl group or an alkylphenyl group in which the alkyl moiety contains 1 to 3 carbon ~ -atoms and the phenyl moiety i 9 optionally substitu~ed9 R4 is a hydroxyl group, or a group OR6 wherein R6 is a C2 7 acyl group, a Cl 4 alkyl group9 or : "

~ -2- ~ ~ ~

optionally substituted benzyl group; R5 is hydrogen or a Cl 5 alkyl group;
or R4 and R5 together with the carbon atom to which they are joined represent a carbonyl group.
In formula (I) R3 will often be a Cl 5 alkyl group, a C3 6 cycloalkyl group or an alkylphenyl group in which the alkyl moiety contains 1 to 3 carbon atoms and the phenyl group is optionally substituted.
Suitable examples of R3 includes the following group:
methyl, ethyl, propyl, cyclopropyl, cyclopentyl, cylcohexyl, benzyl and phenyl-ethyl. The phenyl moieties of the benzyl and phenylethyl groups may be sub-stituted by, for example, a Cl 4 alkyl, halogen or nitro group. R3 may alsosuitably be an allyl or butenyl group. Preferably R3 is a methyl, ethyl or n-or iso-propyl group, most preferably a methyl group.
R4 is most suitably a hydroxyl group. However, when R~ is a group OR6, suitable examPles of R6 include the following groups; acetyl, n- and iso-propionyl, n-, sec- and te t-butyryl, caproyl, heptanoyl, methyl, ethyl, n- and .. , . . . ~.
iso-propyl and n- sec- and tert- butyl, and benzyl. The phenyl moiety of the benz-yl grouD maY be substituted by~ for example~ a Cl 4 alkyl, halogen or nitro group.
Suitable e~amples of R5 include hydrogen, and the methyl, ethyl, n-and iso- propyl, and n- butyl groups. Preferably R5 is hydrogen or a methyl group, most preferably hydrogen. Suitably R4 has the~ configuration.
A preferred class of compounds of the formula (I) are those of the formula (II):

~`\ ~/~ XR ( I l ) .; . ~ . ....
;~ ~ wherein:

R7 is a hydroxyl group ? or a hydroxy group acylated by a C2 7 acyl group; R8 is hydrogen, or a Cl 4 alkyl group; or R7 and R8 taken together with `~ the carbon atom to which they are joined form a carbonyl group; and Rg is a Cl 3 alkyl group.

.
' ~

i38 When R7 is a hydroxyl group acylated by a C2 7 acyl group, it is suitably an acetoxy, n- or iso- propionoxy, caproyloxy or heptanoyloxy group.
R7 is preferably a hydroxyl group.
It is preferred that R7 has the ~ configuration.
R8 is suitably hydrogen or methyl, most suitably hydrogen.
Rg is suitably a methyl or ethyl group, preEerably a methyl group.
Within the compounds of the formula (II), a particularly preferred class of compounds are those of the formula (III):
R R

wherein:
Rlo is a hydroxyl group or a hydroxyl group acylated by a C2 7 acyl group; Rll is hydrogen, or a methyl or ethyl group; or Rlo and Rll taken together with the carbon atom to which they are joined represent a carbonyl group; and

2 is a methyl or ethyl group.
Rxamples of groups Rlo include hydroxyl, acetoxy, n- or iso-pro-pionyloxy, caproyloxy and heptanoyloxy groups.
Preferably, Rlo is a hydroxyl group, and normally the group Rlo will be in the ~configuration.
Preferably Rll i9 hydrogen, or a methyl group, or Rlo and Rll taken together with the carbon atom to which they are joined represent a carbonyl group.
More suitably Rll is a hydrogen atom.
; Preferably R12 is a methyl group. ;~

One compound within the formula (III) of particular utility due to its 5-~-reductase lnhibitory activity is androst-4-en-16,16-dimethyl-17~-ol-3-; one, The invention also provides a process for the preparation of the .
compounds of the formula (13, which process comprises reacting a compound of the formula (IV):
. ~ ~ .
.. .

.

~9~9~il wherein X is a pro~ected carbonyl group and R3 R~ and R5 are as defined in formula (I~ 9 to generate an unprotected carbonyl group in place of the protected carbonyl group X.
The double bond in Eormula (IV) rearranges during the de-protection reaction to glve the desired 4,5 bond in the product.
The process of the invention is a conventional de-protection of a protected carbonyl group. Thus the group X may be a ketalised carbonyl group, for example (CH )~ \C wherein n is 2 or 3 or R X wherein RlX is an alcohol O R~
or thiol residue (X being oxygen or sulphur respectively), in which case the de-protection is suitably carried out by acid hydroIysis; or it may be a thioketalised carbonyl group, such as (CH2~n~\ ~ C or (CH2) \ > C wherein n is 2 or 3, in which case the de-protection may suitably be carried out using mercuric salts, or again by acid hydrolysis.
After this de-protection reaction, if desired the following optional steps may be carried out: ~
(i) when R4 and R5 do not form a carkonyl group the group R4 may be varied by conventional methods. For example, compounds of the formula (I) wherein R4 lS an aFylated or etherified hydroxyl group-may be prepared by conventional acylation or etherificatlon of compounds of the formula (I) wherein R4 ls a hydroxyl group. Such reactions lnclude reaction of the hydroxyl moiety wlth acyl chlorides or acyl anhydrides such as acetyl chloride or acetic anhydride under anhydrous conditions to give acyl derivatlvesJ and reaction of ~
..

a sodium salt of the hydroxyl moiety with an alkyl halide to give an etheri-fied derivative.
(ii) compounds of the formula (I) wherein there is a 4,5 double bond may be converted to their corresponding saturated analogues by any of the usual reduction methods, such as hydrogenation with a palladium catalyst.
The compounds of the formula (IV) are novel, are useful as in-termediates in the formation of the pharmaceutically active compounds of the formula (I), and as such form part of the present invention.
The compounds of the formula (IV) may themselves ~e prepared by a process which comprises substitutin~ a compound of the formula (V?: :

f`~ (V~ :
- X ~, ~,................................... .
at the 16 positlon with the required groups R3, and thereafter if desired converting the 17-carbonyl group to other groups R4 and R5 by conventional methods; R4 and R5 are as defined in formula (IV). Less preferably, the 16-mono substituted intermediates in this reaction may first be isolated, and then further substituted at the 16 position. -~
The substitution reaction may suitably be carried out by reacting the chosen compound of the formula (V) with a compound R3Y in the presence of a strong base of low nucleophilicity. Suitably Y is a halide, tosylate, mes-ylate or azide, the base is a hydride such as sodium hydride, and the reaction is carried out in anhydrous conditions.
The optional conversion of the 17-carbonyl group into other groups R4 and R5 may be carried out by the usual conventional methods. For example, compounds wherein R4 is a hydroxyl group and R5 is either hydrogen or a Cl 5 alkyl group may be formed from the corresponding 17-carbonyl compound by re-duction or by reaction with a Cl 5 alkyl Grignard reagent or a Cl 5 alkyl metallic complex (suitably a Cl 5 alkyl lithium complex) respectively. The redùction may suitably be carried out using lithium aluminum hydride. There-after if desired, the thus formed R4 hydroxyl group may itself be acylated or .... .. : : . . . .

~6~

etherified to give another graup R4 by methods described in sub-paragraph (i) above.
The compounds o~ the Eormula (V) may be prepared by the oxidation of the corresponding 17-hydroxyl compound of the formula (VI) under neutral or basic conditions:

1/\ ' ~' ( ) ~ ~

wherein X is as defined in formula (V).
This reaction is conveniently carried out using either silver carbonate on an inert support such as Kieselguhr, or Collins' reagent, which is a mixture of chromium trioxide and pyridine in methylene dichloride.
The compounds of the formula (VI) may themselves be prepared by the carbonyl protection of the corresponding compound of the formula (VII):
OH

(VII) 0~ ' This reaction will be carried out under conventional conditions to give the desired protected carbonyl group ~. For example, when a ketalised carbonyl group is required) the compound of tbe formula (VII) is reacted with a suitable alcohol or thiol in the presence of acid. In this way, ethyleneglycol, Eor example, yields the 3,3-ethylenedioxy carbonyl protecting group.
During the reaction, the double bond shifts as shown below.
From the aforesaid description, it can be seen that a particularly suitable preparative route for compounds of the formula (I) is as shown in the diagram below:

.

~ ~ ~7~

~g~

o~ : :
~> (VII ) ¦ ~ ~ proteCtion ¦ ~ ~

OH

~ ~ ox~dation ~y ~ (V) ~/~ 16,16 di-subs ti tution (IV) L^¦~ 3 l ll R3 (IVr ) ~ ~

< op-tional carbonyl conversion.
de-pro tec1;i.on : ,1 -~ 0~ J ' ~ .
~ ~ ' . ''.:

~, . . .
. .

The thus formed compound of the formula (I) may thereafter be con-verted into another compound of the formula (I) if desired by either or both of the optional steps described in preceding sub-paragraphs (i) and (ii).
The present invention also provides a pharmaceutical composition comprising a compound of the formula (I) together with a pharmaceutically acceptable carrier.
The compounds of the invention will normally be made up into a cream or ointment for topical administration to the skin. A preferred comp~
osition according to the inven~ion is therefore a pharmaceutical composition ;10 for topical administration to the skin comprising a compound of the formula ~I) which has been formulated as a cream or ointment.
Cream or ointment formulations that may be used for compounds oE
the formula (I) are conventional formulations well known in the art, for example, as described in standard text books of pharmaceutics and cosmetics, such as Harry's Cosmeticology published by Leonard Hill Books, and the British Pharmacopoeia. A standard emulsifying ointment base or an anhydrous poly-ethylene glycol are simple examples of such suitable formulations.
It is believed that certain of the compounds of the formula (I) ` are active via the oral route. Accordingly such compounds can be formulated with inert carriers into compositions conventional for such administration, such as tablets, capsules, syrups and the like.
The invention also provides a method of treatment oE androgen dependent skin disorders comprising the administration of an effective amount of a compound of t~e formula (I) to the sufferer.
The compounds of the formula (I) are particularly useful in the treatment of acne and se'borrhoea. Specifically then the invention provides a method of treatment of acne Gr seborrhoea comprising the administration of an effective amount of a compound of the formula (I) to the sufferer.
Preferably the compounds of the formula (Ij will be administered topical'ly to the affected skin. ~
The compounds of the invention have the advantage that they ' -combine effective relief in the treatment of androgen dependent skin disor~ers _9_ with no apparent d~leterious hormal side efEects.
It will be appreciated that one or more of the antibacterial agents conventionally used in the treatment of acne and seborrhoea infections may be incorporated into the compositions of the invention when these compositions are to be used for such treatment.
The following Examples illustrate -the preparation of the compounds of the formula (I), and the preparation of their intermediates. A Pharma-cological Section is also included:

-- OI-I

O . . . .
Androstan-5-en-3,3-ethylenedioxy-17~-ol was obtained from androst-4-en-17~-ol-3-one as fine white needles, m.p. 185-186 (from methanol/water), by using the procedure of J.A. Campbell, J.C. ~abcock and J.A. Hogg, J. Am. Chem. Soc., 1958, 80, 4717-4721.

I~
-1~ .

o Silver carbonate on Kieselguhr (20 g) was dried by azoetropically distllling off any moisture with benzene. The oxidising agent was suspended in dry ben~ene (200 ml~ and to this was added androst-5-en-3,3-ethylenedioxy-17~-ol (lg) in benzene (50 ml) and the mixture was refluxed for 4 hours. Complete oxidation was achIeved. The reaction mixture was filtered and the filtrate was evaporated to give androst-5-en-3,3 ethylenedioxy-17-one (0.95g) as fine white needles, m.p. 189-190, from methanol.
Complete oxidation was also achieved using chromium trioxide and pyridine in methylene chloride.

1~06~$313 ~ ~ ~ C~3 <,,1~. ' O

Androst-5-en-3,3-ethylenedioxy-17-one (2.92g) was dissolved in dry tetra~
hydrofuran (60 ml). Sodium hydride (2.92g) was added, following by methyl iodide (5 ml), and the reaction mixture was refluxed for 4 hours. The tetra-hydrofuran was evaporated under reduced pressure and the residue was parti-tioned between ethyl acetate and water. The ethyl acetate layer was washed again with water, dried (anhydrous MgS04) and evaporated to dryness to give a solid (3.21g). This solid was recrystallised from methanol/water to give androst-5-en-3,3-ethylenedioxy-16,16-dimethyl-17-one (2.4g) as colourless crystals, m.p. 138-142.
The following compounds were similarly prepared:

.
Example 3a Androst-5~en-3,3-ethylenedioxy-16,16-diallyl-17-one, m.p. 100-101 (from methanol);~
Example 3b Androst-5-en-3,3-ethylenedioxy-16,16-dibenzyl-17-one, as a white foram (infra-red car~onyl absorption at~l725cm l);
Exam~le 3c -- ''. :'.
Androst-5-en-3,3-ethylenedioxy-16,16-di-n-butyl 17-one, m.p. 165-167 (from methanol);
Example 3d~
Androst-5-en-3,3-ethylenedioxy-16jI6-die~hyl-17-one, m.p. 146-148 (from methanol).~

,. . ' ,~ ~ ' ; :

-:1 1- - ' .: : : : - ~ ,:, : . , : ~

EXAMPLE 4- ~
12 0~-1 < ~
-O

Androst-5-en,3-ethylenedioxy-lG,16~dimethyl 17 one (1.5g~ ~as d:lssolved in dry ether (100 ml) and lithium aluminum hydride (O.lg) was added. The r~action mixture was stirred a~ room t~mperature for 30 minutes and then excess of hy-dride was destroyed by adding an excess of ethyl acetate. The mixture was then shaken with a solution of potassium sodium tartrate, the organic phase was separated and washed with water before being dried over anhydrous MgS04.
Filtration and evaporation of the filtrate to dryness gave ~
ethyl-enedioxy-16,16-dimethyl-17~3~ol ~1.47g) as a white powder, m.p. 178-179, from ethyl acetate. -The following compound was similarly prepared:
; Example 4a Androst-5-en-3,3-ethylenedioxy-16,16-diallyl-17~ol, m.p. 149-151.
EXA~LE 5 O J , ~ ~;
Androst-5-en-3,3-ethylenedloxy-16,16-dimethyl-175-ol (lg) was dissolved in methanol (30 ml) and 2.5N hydrochloric acid (5 ml) was added. The mixture was , , .
refluxed for 1 hour to achieve complete hydrolysis of the ketal. The reac~ion ~ ~
.
mixture was taken up in an excess of ethyl acetate and washed with water un~il neutral. The organic phase was~ drled over MgS04,~ filtered and the fil~rate evaporated to dryness to give a white solid (0.88g). Recrystallisation from ` -20 ~ petroleum ether (60 - 80 )/ethyl acetate gave androst-4-en-16~16-dimethyl- 17~ol-3 one (0~75g) as white needles, m.p. 170-172.
.:

-l2--~6~?8 The following compounds was similarly prepared:

~xample 5a Androst-4-en-16,16-diallyl-17~-ol-3-one, as a thick oil with an infra-red carbonyl absorption at 1680cm 1. ---RXAMPLE 6 ~ ¦ C~3 ~ CH3 0// ~ ~

Androst-5-en-3,3-ethylenedioxy-16,16-dimethyl-17-one (0.25g) was dissol~ed in methanol (7.5 ml) and 2.5N hydrochloric acid (1.5 ml) was added. The solution was refluxed for 30 minutes and, after cooling, an excess of ethyl acetate was added. The organic phase was washed with water until neutral, then dried (anhydrous MgS04) and evaporated to dryness yielding a white solid (0.2g) which was recrystallised from petroleum ether (60 -8~ ) to give androst-4-en-16,16-dimethyl-3,17-dione (0.16 g) as white needles, m.p. 164-165.
The following compounds were similarly prepared:
Example 6a Androst-4-en-16,16-diallyl-3,17-dione, m.p. 118-120 (from petroleum ether 60-80);
Example 6b Androst-4-en-16,16-dibenzyl-3,17-dione, m.p. 150-152 (from petroleum ether 60-80);
Example 6c Androst-4-en-16,16-di-n-butyl-3,17-dione, as a thick oil with infra-red carbonyl :.
absorptions at 1680cm 1 and 1720cm 1.

am21e 6d Androst-4-en-16,16-diethyl-3,17-dione, as a semi-crystallised oil with infra-red carbonyl~absorptions at 1680cm 1 and 1720cm 1.
~~~~~~~~~~~~~ OCOCH, ~ ~ CM3 `.,.. ~, :

Androst-4-en-16l16-dimethyl-17~-ol-3-one (0.158g) was dissolved in dry benzene (4 ml) and dry pyridine (0.14g) and acetyl chloride (0.12g) were added. The mixture was refluxed for 30 minutes, cooled and poured into an excess of ethyl acetate. The ethyl aceta~e solution was washed with dilute hydrochloric acid and then water before being dried over anhydrous MgS04. Filtration and eva-poration of the filtrate to dryness gave a solid ~0.156g~ which was recrystall- I -ised from petroleum ether (60-oO) to give androst-4-en-16,16-dimethyl-17r~- ol- !

3-one acetate (O.lOOg) as white needles1 m.p. 153-155 .
The following compound was similarly prepared: ¦
Example 7a Androst-4-en-16,16-dimethyl-17~-ol-3-one hexanoate, m.p. 105-107 (from methanolj.

, OH

C
"" ', .
0 1, :

Androst-5-en-3,3-ethylenedioxy-16?16-dimethyl-17-one (0.5g) was dissolved in dry ether and mai~tained in a nitrogen atmosphere. A large excess of methyl lithium (20 ml of a 1.75M solution in hexane) was added over a 10 minute period A precipitate formed immediately. The mixture was stirred for 2 hours at room temperature before the excess of methyl lithium was destroyed by areful I addition of water. The product was extracted with ethyl acetate and the organic phase was washed with water, dried (anhydrous MgS04) and evaporated to dryness to yield a white solid (O.Slg). This solid was recrystallised fr~m petroleum ether (60 -80 ) to give androst-5-en-3,3-et~ylenedioxy-16,16,17Q-trimethyl-. .
17 ~ol (0.40g) as white crystals, m.p. 170-171. ¦
EXAMPLE 9 C~3 ~1 o ~

Androst-5-en-3,3-ethylenedioxy~16,16-17~trimethyl-17~-ol (l.lg) was dissolved in methanol (50 ml) and 2.5N hydrochloric acid (10 ml) was added. The mixture was refluxed for 15 minutes. The product was extracted with ethyl acetate and the organic layer was washed with water until neutral. After drying over an-hydrous MgS04 and filtration, the filtrate was evaporated to dryness to give a crude solid (0.94g). This solid was recrystallised Erom petroleum ether (60-80) to give an_rost-4-en-16,16,17~-trimethyl-17~ ol-3-one (0.54g) as white flakes, m.p. lS5-166 .
Pharmacological Section 1. Androgenic/anabolic test and Anti-androgenic test The method used was basically that of Hershberger et al., Proc.
Soc. Exp. Biol. Med., 83, 175, (1953) with minor modifications.
I~mature male rats weighing 50-60gwere castrated under nembutal anaesthesia. The animals were dosed for four days starting on the ~ifth day after castration. The body weights of the animals were recorded during the dosing period. On the tenth day after castration the animals were sacrificed and the weights of the seminal vesicles, ventral prostate, levator ani muscle and thymus were measured, together with the total body weight. These data were then compared with data from control animals. Compounds were made up as sol-utions or suspensions in arachis oil and they were dosed subcutaneously.
Androgenic/anabolic tests For this test the compounds were given at 50 mg/kg, subcutaneously, and the results compared with control animals given testosterone at 1 mg!kg, subcutaneously. Both sets of data were compared with that ~rom castrated, undosed control animals.
Anti-androgenic test For this test the compounds were given at 50 mg/kg, subcutaneously, concomitantly with testosterone at 1 mg/kg, subcutaneously, to determine the degree of inhibition compared with control animals given testosterone at 1 mg/kg, subcutaneously. Both sets of data were compared with that from castrated, undosed control animals.

~15-' :

~6~9~3 Androgenic responseAnti-androgenic data Compound % Rel. potency to% Inhibition of Example testoster, ~ne Seminal Prostate Seminal Prostate _ _ 0.15 0.36 12.1 14.4 ___. ~ .
6 _ _ 17,8 35.0 ` _9 _ ~ = ~ ~ ~ _ l9 _ 2. Androgen displacement experiments The ability of compounds to displace [3H3 -5c~-dihydrotestosterone from high affinity cytosol androgen binding proteins isolated from rat prostate and epididymis was examined in vitro using the method of W.l.P. Mainwaring, F.R.
Mangan, P.A. Feherty and M. Freifeld, Molecular and Cellular Endocrinology, 1974, , 113-128.
Samples of cytosol (0.1 ml) were incubated overnight in the presence of 5 x 10 1 M ~ H] -5~ -dihydrotestosterone (47 Ci/mmole, The Radiochemical Centre, Amersham~ either alone or together with the compound to be tested at 5 x 10 6, 5 x 10 7 and 2.5 x 10 7M. The ability of compounds to displace [ H~ -5C~-DHT from the binding proteins was seen as a lowering of the counts bound in the supernatant.

.
. .

:

- - , . : : ': : . , . ' . . . :, .

% Displacement of [ H~ -5C~-dihydrotestosterone from androgen binding proteins [ H3 -5~ -DHT concen~ration 5 x 10 M

2.5 x 10 M 5.0 x 10 M - 5.0 x 10 M
_ _ _ Compound Prostate Epididymis Prostate Epididymis Prostate Epldidymis _. _ . _ _ 9~ 32 0 _ 46 ~ 4 88 8 3, Inhibition of Test sterone 5C~-reductase Determination of the activity of this enzyme ( A -3~ketosteroid 5 a-reductase) was per~ormed essentîally as described ~y W.I.P. Mainwaring and F.R. Mangan, J. Endocrinology, 1973, 59, 121-139.
The percentage conversion of testosterone (T3 to 5CX-dihydrotestosterone (DHT) in this system ranged from 15 to 30% with various preparations. Inhlbition of conversion was seen by a reduction in the cpm associated with DHT.
cpm DHT
% conversion = - x 100 cpm T + cpm DHT
% inhibition = % conversion without compound - % conversion with compound % converslon without compound ' :

,: ' : ' ; ;

. :
- 16a -- .:. - ... . : . . : : : :

~16~

% Inhibition of 5cX-reductase Compound Compound at 1 ~ 10 M
. ..
30.0 (3) .
6 23.1 (2~
_ _ 9 27.3 (2) :' ( ) The figures in brackets represent the number of experiments.

4. The effect of compounds *n the_testosterone-induced growth of the hamster flank organ In castrated male hamsters of unoperated female hamsters the flank olgan (a sebaceous gland) can be stimulated to grow by topical applicat$on of testosterone. Testosterone is con~erted in this gland to 5 ~-dLhydrotestosterone, (S. Takayashu and K. Adachi, Endocrinology, 1972, 90, 73-80) which is now thought to be the active androgen in most androgen-dependent target organs. The ability of compounds to inhibit this stimulation was assayed essentially using the method described by W. Voight and S.L. ~sia, Endocrinology, 1973, 92, 1216-1222.

.

~ ~ - 17 ~ -::

~ . . , : .:

~,o~3~6~,~

Adult male hamsters were castrated via the scrotal route. One week later they were div~ded into groups of 4 animals and treated as follows. One group was left untreated. A second received acetone alone to the flank organ of the left side o~ thç animal and acetone containing 4~ g of testosterone per day to the right side flank organ. Other groups received acetone alone to the left side flank organ and ace~one containing 4,~g of testosterone plus ~00~ g of compound per day to the right side flank organ.
At the end of three weeks treatment, the animals were kil]ed, the organs measured and placed in fixative for histological examination.
An active compound would inhibit the testosterone-induced growth of the flank organ. Some of the compounds notably compounds such as 5, 6 and 9, were very effective in inhibiting the stimulation of the gland by testo~
sterone. Histological examination confirmed that there had been a conslderable reduction in the size of the sebaceous glands of the flank organ.

5. The effect of compounds on sebum secretion in the rat The ability of the compounds to inhibit sebum secretion in rats was determined essentially by the method described by F.J. Ebling, J. of Investi-gative Dermatology, 1974~, 62, 161-171 and references therein.
Some Oe the compounds such as 5, 6 and 9, and in particular Compound 5, were very effective in inhibiting testosterone stimulated sebum secretion in castrated male rats at 25 mg/kg, subcutaneously, but were ineffective in inhib-iting 5~-dihydrotestosterone stimulated sebum secre~ion at the same dose level.
This would indicate that such compounds were actlng via 5d-reductase inhibition and not via a classical anti--androgenic mechanism.

6. Toxicity :
. .~ . .
No toxic symptoms were detected when compound 5 was dosed up to 90Q mg/kg, orally, in mice.
.
: :, . ~ ' .

: - :
~,, ,

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for preparing a compound of the formula I or a pharmaceutically acceptable salt thereof:

(I) wherein:
R3 is a C1-5 alkyl group, a C3-6 alkenyl group, a C3-6 cycloalkyl group or an alkylphenyl group in which the alkyl moiety contains 1 to 3 carbon atoms and the phenyl moiety is unsubstituted or substituted by inert substituents;
R4 is a hydroxyl group, or a group OR6 wherein R6 is a C2-7 acyl group, a C1-4 alkyl group, or an unsubstituted or substituted by inert substituents benzyl group; R5 is hydrogen or a C1-5 alkyl group; or R4 and R5 together with the carbon atoms to which they are joined represent a carbonyl group;
said process comprising reacting a compound of the formula IV:

(IV) wherein:

X is a protected carbonyl group and R3, R4 and R5 are as hereinbefore defined, to generate an unprotected carbonyl group in place of the protected carbonyl group X and, where required, converting the product to a pharmaceutically acceptable salt thereof.

2. The process of claim 1, wherein R3 is a C1-5 alkyl group, a C3-6 cycloalkyl group or an alkylphenyl group in which the alkyl moiety contains 1 to 3 carbon atoms and the phenyl group is unsubstituted or substituted by inert substituents.

3. The process of claim 2, wherein R3 is a methyl, ethyl or propyl group.

4. The process of claim 1 or claim 2, wherein R3 is an allyl or butenyl group.

5. The process of claim 3, wherein R3 is a methyl group.

6. The process of any of claims 2, 3 and 5, wherein R4 is a hydroxy group or a hydroxy group acylated by a C2-7 acyl group, and R5 is hydrogen.

7. The process of any of claims 2, 3 and 5, wherein R4 is a hydroxy group, or a hydroxy group acylated by a C2-7 acyl group, and R5 is a methyl or ethyl group.

8. The process of any of claims 2, 3 and 5, wherein R4 and R5 together with the carbon atom to which they are joined represent a carbonyl group.

9. The process of claim 1, wherein R4 is a hydroxyl group or a hydroxyl group acylated by a C2-7 acyl group; R5 is hydrogen, or a methyl or ethyl group; or R4 and R5 taken together with the carbon atom to which they are joined represent a carbonyl group; and R3 is a methyl or ethyl group.

10. The process of claim 9, wherein R4 is a hydroxy, acetoxy, n- or iso-propionoyloxy, caproyloxy or heptanoyloxy group.

11. The process of claim 10, wherein R4 is a .beta.-hydroxy group.

12. The process of claim 11, wherein R5 is hydrogen.

13. The process of claim 1, wherein said compound of formula I is androst-4-en-16,16-dimethyl-17.beta.-ol-3-one.

14. A compound of the formula I or a pharmaceutically acceptable salt thereof:

(I) R3 is a C1-5 alkyl group, a C3-6 alkenyl group, a C3-6 cycloalkyl group or an alkylphenyl group in which the alkyl moiety contains 1 to 3 carbon atoms and the phenyl moiety is unsubstituted or substituted by inert substituents;
R4 is a hydroxyl group, or a group OR6 wherein R6 is a C2-7 acyl group, a C1-4 alkyl group, or an unsubstituted or substituted by inert substituents benzyl group; R5 is hydrogen or a C1-5 alkyl group; or R4 and R5 together with the carbon atoms to which they are joined represent a carbonyl group;
whenever prepared by the process of claim 1 or by an obvious chemical equivalent thereof.

15. A compound of the formula I as defined in claim 2 or a pharma-ceutically acceptable salt thereof, whenever prepared by the process of claim 2 or by an obvious chemical equivalent thereof.

16. A compound of the formula I as defined in claim 3 or a pharma-ceutically acceptable salt thereof, whenever prepared by the process of claim 3 or by an obvious chemical equivalent thereof.

17. A compound of the formula I as defined in claim 5 or a pharma-ceutically acceptable salt thereof, whenever prepared by the process of claim 5 or by an obvious chemical equivalent thereof.

18. A compound of the formula I as defined in claim 9 or a pharma-ceutically acceptable salt thereof, whenever prepared by the process of claim 9 or by an obvious chemical equivalent thereof.

19. A compound of the formula I as defined in claim 10 or a pharma-ceutically acceptable salt thereof, whenever prepared by the process of claim 10 or by an obvious chemical equivalent thereof.

20. A compound of the formula I as defined in claim 11 or a pharma-ceutically acceptable salt thereof, whenever prepared by the process of claim 11 or by an obvious chemical equivalent thereof.

21. A compound of the formula I as defined in claim 12 or a pharma-ceutically acceptable salt thereof, whenever prepared by the process of claim 12 or by an obvious chemical equivalent thereof.

22. Andros-4-en-16,16-dimethyl-17.beta.-ol-3-one or a pharmaceutically acceptable salt thereof, whenever prepared by the process of claim 13 or by an obvious chemical equivalent thereof.