The present invention relates to new 6-difluoromethylen- androstenones, to a process for their preparation, to pharmaceutical compositions containing them, and to their use as therapeutic agents, in particular in the treatment of hormone-dependent diseases in mammals. Basic and clinical data indicate that aromatized metabol¬ ites of androgens, i.e. the estrogens, are the hormones involved in the pathogenic cellular changes associated with the growth of some hormone-dependent cancers, such as breast, endometrial and ovarian carcinomas. Estrogens are also involved in the pathogenesis of benign prostatic hyperplasia.

Endogenous estrogens are ultimately formed from either an- drostenedione or testosterone as immediate precursors. The reaction of central importance is the aromatization of the steroidic ring A, which is performed by the enzyme aromatase. As aromatization is a unique reaction and the last in the series of steps in the biosynthesis of estro¬ gens, it has been envisaged that an effective inhibition of the aromatase, resulting from compounds able to interac with the aromatizing steps, may have useful application fo

- 2 -

controlling the amount of circulating estrogens, estrogen- dependent processes in reproduction, and estrogen-dipend- ent tumours.

Known steroidal substances which have been reported to be endowed with an aromatase-inhibiting action are, for ex¬ ample, Δ -testololactone (U.S. Pat. 2,744,120), 4-hydroxy- androst-4-ene-3, 17-dione and esters thereof (see, for ex¬ ample, U.S.Pat. 4,235,893), 10-(l,2-propadienyl)—estr-4-ene-3,17- dione (U.S.Pat.4,289,762), 10—(2-propynyl)-estr-4-ene-3,17-dione (J. Amer.Chem.Soc. , 103, 3221 (1981) and U.S.Pat.4,322,416), 19-thioan- drostene derivatives ( Europ . Pa . Appl . 100 , 566 ) , androsta-4 , 6-diene-3 , 17-dione, androsta-l,4,6-triene-3,17-dione (G.B.Pat.Appl.2,100,601A) , androsta-1, 4-diene-3, 17-dione (Cancer Res. (Suppl.) 42,

3327 (1982)), 6 -al enylen-androsta-1, 4-diene-3 , 17-diones (U.S.Pat. 4,808,816 and U.S.Pat. 4,904,650) and 6-alkenyl- en-androsta-1, -dien-17-ol-3-one derivatives (U.S. Pat.

4,873,233).

The present invention provides new compounds having the following general formula (I)

wherein the symbol represents a double or single bond;

- 3 -

R is hydrogen or C-,-C alkyl; and

A is a or CHv- DR group, in which R is an acyl group.

Compounds falling within the scope of formula (I) above are all the possible isomers, stereoiso ers and their mixtures, and the metabolites and the metabolic precursors or bio- precursors of the compound of formula (I). In the formulae of this specification the heavy solid lines (•----■ ) indicate that a substituent is in the /-.-configuration, i.e. above the plane of the ring, whereas a dotted line ( ^• ..- ^•• ) indicates that a substituent is in the α-configuration, and a wavy line (Λ«) indicates that a substituent may be either in the α-configuration, i.e. below the plane of the ring, or in the /3-configuration or in both, i.e. a mixture thereof.

In particular when in the compounds of formula (I) A is

-CH-Λ.0H or -CH v-OR the OH or OR substituent may be either in the *X- or in the β-configuration or in both, i.e. a mix¬ ture thereof. Analogously, when the symbol is a single bond, the R substituent may be either in the α- or jS-configuration or in both, i.e. a mixture thereof.

The present invention includes all the possible isomers, e.g. the single 10 _> , 170(; lo^,17B; lβ,170( and lβ,17β epimers, as well as all possible mix- tures thereof, e.g. i(0(,β) , 170(; l(0(,β),17β; 1 , 17(D(,β) ;

- A -

li_ , 17 (o( , β ) and lfa,β) ,17(α( ,β)-isomers of the compounds of formula (I). Hence a compound of the invention herein spe¬ cifically mentioned, without any indication of its stereo¬ chemistry, represents all the possible single isomers or mixtures thereof.

A -C alkyl group is preferably a methyl or ethyl group, more preferably a methyl group. The alkyl radical may be a branched or straight chain radical. R as an acyl group may be residue of any physiologically tolerable acid. Preferred examples of said acids are

C^Q al anoic acids, in particular acetic, propionic and butyric acids.

As stated above, the present invention also includes with¬ in its scope pharmaceutically acceptable bio-precursors (otherwise known as pro-drugs) of the compounds of formula (I), i.e. compounds which have a different formula to for¬ mula (I) above but which nevertheless upon administration to a human being are converted directly or indirectly in vivo into a compound of formula (I). Preferred compounds of the invention are the compounds of formula (I) wherein

I i

A is a -C=0 or -CH.w-.0H group; R is hydrogen; and the symbol represents a single or.double bond. Examples of specific compounds of the invention are the

following compounds which, when appropriate, may be either z - or β-epimers or <χ,β-mixtures of said epimers:

6-difluoromethylenandrost-4-ene-3, 17-dione; 6-difluoromethylenandrost-4-en-17(X-ol-3-one ; 6-difluoromethylenandrost-4-en-17β-ol-3-one; 6-difluoromethylenandrosta-1,4-diene-3, 17-dione; 6-difluoromethylenandrosta-1,4-dien-170(-ol-3-one ; and 6-difluoromethylenandrosta-1, 4-dien-17B-ol-3-one.

The compounds of the invention can be obtained by a process comprising: a) dehydrofluorinating a compound of formula (II)

wherein R is as defined above, thus obtaining a compound of for¬ mula (I) wherein the symbol is a single bond and

A is a ^.CO group; or b) dehydrogenating a compound of formula (III)

6 -

wherein

R is as defined above , thus obtaini ng a compound of for¬ mula ( I ) wherein the symbol is a double bond and

A is a H-CO group; or c) reducing selectively a compound of formula (IV)

wherein

R and the symbol are as defined above, thus obtain¬ ing a compound of formula (I) wherein R and the symbol are as defined above and A is a ^,C_-v*-0 ^~~ group; or d) acylating a compound of formula (V)

wherein

R and the symbol are as defined above, thus obtain¬ ing a compound of formula (I) wherein R and the sym _b ol

are as defined above and A is group in which R is an acyl group; and, if desired, converting a compound of formula (I) into another compound of for¬ mula (I), and/or, if desired, separating a mixture of isomers of compounds of formula (I) into the single isomers.

The dehydrofluorination of a compound of formula (II) can be carried out by using basic dehydrohalogenation agents such as pyridine or a LiBr-Li ₂ C0 ₃ -DMF mixture. Preferably the dehydrofluorination is carried out by chromatographing the raw steroid on neutral or basic alumina and using as eluant an inert solvent such as benzene, dichloromethane or ethyl acetate. The dehydrogenation of a compound of formula (III) may be performed according to known methods, e.g. by treatment with DDQ, according to D. Walker and J.D. Hiebert: Chem. Rev. _6_7, 156 (1967), or by treatment with selenium dioxide, chloranil or benzeneseleninic acid. Preferably the reaction is performed by treatment with benzeneseleninic anhydride in an inert organic solvent, such as chlorobenzene or car¬ bon tetrachloride, at a temperature ranging from about 60°C to about 120°C and reaction times varying from about 2 to about 48 hours. The selective reduction of a compound of formula (IV) may e carried out by a well known method, for example as des-

cribed by C. Djerassi in Steroid Reactions (1963) or by J. Fried in Organic Reactions in Steroid Chemistry Vol.I (1972) . Preferably the reduction is carried out with a com- plexed metal hydride, in particular with sodium borohydr- ide in an inert organic solvent, in particular in methanol solution at temperatures ranging from about 0 to about 50°C.

The acylation of a compound of formula (V) can be perform¬ ed by reaction with a reactive derivative of a suitable carboxylic acid, such as an anhydride or halide, in the presence of a basic agent, at temperatures ranging from about 0 to about 50°C. Preferably the acylation is carried out by reaction with the respective anhydride in the pres¬ ence of an organic base, such as pyridine. The separation of a mixture of isomers into the single isomers as well as the conversion of a compound of formula (I) into another compound of formula (I) may be carried out according to known methods. For example a 17β-hydroxy derivative of a compound of formula (I) may be converted into the respective 17c^-hydroxy derivative by basic cata¬ lysis, e.g. with 0.1N sodium hydroxide in an aliphatic al¬ cohol, e.g. ethanol.

Similarly, processes b), c) and d) can be regarded as op¬ tional conversions of a compound of formula (I) into an- other compound of formula (I). In fact, a compound of for-

- 9 -

mula (III) is a compound of formula (I) wherein the symbol is a single bond, A is ^C0 and R is as herein defined.

A compound of formula (IV) is a compound of formula (I) wherein A is CO and the symbol and R are as herein defined; and a compound of formula (V) is a compound of formula (I) wherein A is and the symbol and

R are as herein defined.

A compound of formula (II) can be obtained by oxidizing a compound of formula (VI)

OH

wherein R is as defined above.

The oxidation of a compound of formula (VI) can be per¬ formed according to known methods, e.g. by treatment with the Jones reagent as described by Fieser and Fieser in Reagents for Organic Synthesis 1_, 142 (Wiley 1967). Jones reagent is a solution of chromic acid and sulfuric acid in water. The oxidation may be carried out by titrating a stirred solution of the alcoholic compound in acetone at temperatures ranging from about -20°C to about 30°C with the Jones reagent.

- 10 -

A compound of formula (VI) wherein R is as defined above may be obtained by saponification of a compound of for¬

wherein R is as defined above and R , being as herein de¬ fined, is preferably a lower alkanoyl group, in particular acetyl.

The saponification may be performed by a conventional method, e.g. by treatment with an alkali metal hydroxide in alcoholic solution, preferably with potassium hydroxide in methanol or ethanol at temperatures ranging from about 20°C to reflux temperature.

A compound of formula (VII), wherein R and R are as de¬ fined above, may be obtained from a compound of formula (VIII)

- 11 -

wherein R and R are as defined above by applying e.g. the method described in U.S. Pat. 3,504,002. Accordingly, the 6-ketosteroid of formula (VII) is treated with at least equimolar amounts of tributylphosphine and sodium chloro- difluoroacetate, at a temperature in the range of 150 - 200°C, using as solvent disubstituted hydrocarbon amide. It is viewed as involving the in situ production of tri- butylphosphinedifluoromethylene, which reacts with the 6-keto group. Alternatively, the method mentioned in U.S. Pat. 4,567,000 can be used. Accordingly, a solution of the protected 6-ketosteroid in an inert solvent such as THF, dioxane or diglyme is added to a cold solution of (di- ethylphosphinyl)difluoromethyllithium at about -60°C to about -80°C. This reagent may be prepared by treatment of diethyl difluoromethylphosphonate with 1.1 equivalent of lithium diisopropylamide in THF at -78 ^C C.

A compound of formula (VIII) wherein R and R are as de¬ fined above may be obtained by oxidation of a compound of formula (IX)

- 12 -

in which R and R _{ are as defined above. This conversion may be performed according to a well known oxidation method in steroi _d c _h emistry, e.g. according to the method described above.

_A compoun _d o _f formula (IX) wherein R and Rj are as defined a _b ove may _b e o _b tained by cleavage of the 5/3,6?-epoxide ring in a compound of formula (X)

wherein R and R are as defined above. The cleavage may be carried out, e.g., accordingly to

H.B. Henbest et al. (J. Chem. Soc. 1957, 4765) by reaction with the boron trifluoride-ether complex in an inert or¬ ganic solvent such as benzene or ethyl ether at tempera¬ tures ranging from about 0 to 50°C. In the case of 5.6B- epoxide, the cleavage affords the diaxial 50(,6β-fluoro- hydrin as desired.

A compound of formula (X) , wherein R and R are as defin _¬ ed above, may be obtained from a compound of formula (XI)

- 13 -

wherein R and R are as defined above; by dehydrobromination, e.g. according to J.F. Templeton et al. in J. Chem. Soc. Perkin Trans. I, 1361 (1987). Thus a solution of the 5Q,6fl-bromohydrin in an inert organic solvent, such as dichloromethane or THF, is stirred with basic alumina at room temperature. Alternatively, the 5θ,6β-bromohydrin can be treated with a weak base such as sodium acetate in alcoholic solution, e.g. in methanol, at temperatures ranging from about 20°C to reflux tempera¬ ture, e.g. as described in Belg. Pat. 625,669.

A compound of formula (XI), wherein R and R are as defin¬ ed above, may be obtained from a compound of formula (XII)

wherein R and R are as defined above; by treatment with a N-bromoamide such as N-bromoacetamide or N-bromosuccinimide in the presence or not of perchloric acid in an aqueous solvent mixture such as aqueous dioxan or aqueous 1,2-dimethoxyethane at temperatures ranging from about 0°C to room temperature, e.g. as described in J. Chem. Soc. 1959, 4108.

The compounds of formula (XII) are known compounds or may be obtained by known methods from known compounds. When in the new compounds of the present invention and in the intermediate products thereof groups are present which need to be protected before submitting them to the here- above illustrated reactions, they may be protected before the reactions take place and then deprotected at the end of the reaction, according to well known methods in organ¬ ic chemistry.

The compounds of the present invention are inhibitors of the biotransformation of androgens into estrogens, i.e., they are steroidal aromatase inhibitors. The aromatase inhibitory activity of these compounds was demonstrated by employing the in vitro test described by Thompson and Siiteri (E.A. Thompson and P.K. Siiteri, J. Biol. Chem. 249, 5364, 1974) which utilizes the human pla- cental microsomal fraction as enzyme source. In this test the aromatization rate of androstenedione into estrone was

3 evaluated by incubating (IB- H)androstenedione (50 nM) in the presence of NADPH with the enzyme preparation and by

3 measuring the amount of H O formed during 20 min incuba¬ tion at 37°C. The compounds, incubated at various concentrations, showed a relevant aromatase inhibitory activity.

By virtue of their ability to inhibit aromatase and, con¬ sequently, to reduce estrogen levels, the compounds of the invention are useful in mammals, including humans, in the treatment and prevention of various estrogen-dependent dis¬ eases, i.e. breast, endometrial, ovarian and pancreatic cancers, gynecomastia, benign breast disease, endometriosis, polycystic ovarian disease and precocious puberty. Another application of the compounds of the invention is in the therapeutic and/or prophylactic treatment of prostatic hyperplasia, a disease of the estrogen-dependent stromal tissue.

The compounds of the invention can find also use for the treatment of male infertility associated with oligospermia and for female fertility control, by virtue of their abil¬ ity to inhibit ovulation and egg nidation. In view of their low toxicity the compounds of the invention can be used safely in medicine. For example, the approximate acute toxicity (LD ) of the compounds of the invention in the mouse, determined by single ad inis-

- 16 -

tration of increasing doses and measured on the seventh day after the treatment was found to be negligible. The compounds of the invention can be administered in a variety of dosage forms, e.g. orally, in the form of tab- lets, capsules, sugar or film coated tablets, liquid solu¬ tions or suspensions; rectally, in the form of suppositories; parenterally, e.g. intramuscularly, or by intravenous in¬ jection or infusion. The dosage depends on the age, weight, conditions of the patient and admininistration route; for example, the dos¬ age adopted for oral administration to adult humans may range from about 10 to about 150-200 mg pro dose, from 1 to 5 times daily. The invention Includes pharmaceutical compositions com- prising a compound of the invention in association with a pharmaceutically acceptable excipient (which can be a car¬ rier or diluent) .

The pharmaceutical compositions containing the compounds of the invention are usually prepared following conven- tional methods and are administered in a pharmaceutically suitable form.

For example the solid oral forms may contain, together with the active compound, diluents, e.g. lactose, dextrose, saccharose, cellulose, corn starch or potato starch; lu- bricants, e.g. silica, talc, stearic acid, magnesium or

calcium stearate, and/or polyethylene glycols; binding agents, e.g. starches, arabic gums, gelatin, methylcel- lulose, carboxymethylcellulose or polyvinyl pyrrolidone; disaggregating agents, e.g. a starch, alginic acid, al- ginates or sodium starch glycolate; effervescing mixtures; dyestuffs, sweeteners; wetting agents, such as lecithin, polysorbates, laurylsulphates; and, in general, non-toxic and pharmacologically inactive substances used in pharma¬ ceutical formulations. Said pharmaceutical preparations may be manufactured in known manner, for example, by means of mixing, granulating, tabletting, sugar-coating, or film-coating processes. The liquid dispersions for oral administration may be e.g. syrups, emulsions and suspen¬ sions. The syrups may contain as carrier, for example, saccharose or saccharose with glycerine and/or mannitol and/or sor¬ bitol.

The suspensions and the emulsions may contain as carrier, for example, a natural gum, agar, sodium alginate, pectin, ethylcellulose, carboxymethylcellulose, or polyvinyl al¬ cohol .

The suspensions or solutions for intramuscular injections may contain, together with the active compound, a pharma¬ ceutically acceptable carrier, e.g. sterile water, olive oil, ethyl oleate, glycols, e.g. propylene glycol, and if

desired, a suitable amount of lidocaine hydrochloride. The solutions for intravenous injections or ^' infusions may contain as carrier, for example, sterile water or preferably they may be in the form of sterile, aqueous, isotonic saline solutions.

The suppositories may contain together with the active compound a pharmaceutically acceptable carrier, e.g. cocoa-butter, polyethylene glycol, a polyoxyethylene sorbitan fatty acid ester surfactant or lecithin. The present invention also provides a compound of formula (I) for use in a method of treatment of the human or animal body by therapy, especially for use as an aromatase inhibitor.

The present invention additionally provides the use of a compound of formula (I) in the manufacture of a medicament for use as an aromatase inhibitor.

The present invention further provides a method of inhibiting aromatase in mammals, including humans, which comprises applying thereto an effective amount of a compound of formula (I) .

The present invention still further provides an aromatase inhibiting agent comprising a compound of formula (I) . The following examples further illustrate the invention: Example 1 (I, A= -C=0, R=H, --- single bond)

First Jones reagent is prepared by dissolving 2.672 g of chromic trioxide in 2.3 ml of cone.sulfuric acid and di _¬ luting with water to a volume of 10 ml. Then to a stirred solution of 6-difluoromethylene-5σ-fluoroandrostan-3,17-

STITUTE SHEET

- 13 -

diol (358 mg, 1 mmol) in acetone (30 ml) is added portion- wise under cooling 2 ml Jones reagent. After stirring for h at 10-15°C and another^ h at 20-25°C, methanol (1 ml) is added to destroy excess reagent. The resultant green solution is filtered to remove the chromium salts and then carefully diluted with water in order to precipitate raw 6-difluoromethylene-5-i-fluoroandrostan-3,17-dione. The precipitate is filtered off, desiccated, dissolved in

benzene (10 ml) and adsorbed onto a basic alumina column (20 g). Finally elution with benzene-ether affords pure 6-difluoromethylene-androst-4-ene-3, 17-dione (167 mg, 50% yield) .

C H F 0 calcd: C 71.83 H 7.23 F 11.36 found: C 71.71 H 7.11 F 11.42 IR cm ^"1 : 1740 (17-CO), 1725 (C=CF ), 1670 (3-C0) , 1620

MS (m/z): 334

Example 2 (I, A= ^C=0, R=H, double bond)

A solution of 6-difluoromethylenandrost-4-ene-3, 17-dione (334 mg, 1 mmol) and benzene selenic anhydride (360 mmol) in chlorobenzene (30 mol) is heated for 4 h at 90-100°C. Then the solvent is removed in vacuum and the residue chromatographed on silica gel with benzene-ether mixture as eluant thus giving pure 6-difluorometh lenandrosta-1,4- diene-3, 17-dione (266 mg, 80% yield) .

°20 ^H 22 ^F 2°2 ^{calcd: C 72} - ^{27 H 6} - ^{67 F} 11-43 found: C 72.15 H 6.55 F 11.35

IR cm ^"1 : 1735 (17-C0), 1720 (C=CF ) , 1650 (3-C0), 1610 (Δ ⁴ ) MS (m/z): 332.

Example 3 (I, A= -CH-OH, R=H, single or double bond)

To a stirred solution of 6-difluoromethylenandrost-4-ene- 3,17-dione (334 mg, 1 mmol) in methanol (20 ml) is added sodium borohydride (57 mg, 1.5 mmol) over a period of 10 min at 0°C and stirring is continued for 1 h at 0°C. After addition of few drops of acetic acid, the mixture is con¬ centrated under vacuum, diluted with water and then ex¬ tracted with ethyl acetate. The combined organic phases are washed with saline solution, dried over sodium sulfate and then evaporated in vacuum. The residue is submitted to column chromatography on silica gel. Gradient elution with benzene-ether mixtures affords pure 6-difluoromethylen- androst-4-en-17β-ol-3-one (202 g, 60 % yield).

C„--.(JH d _c oF d0 d calcd: C 71.40 H 7.79 F 11.30 found: C 71.31 H 7.68 F 11.15

IR cm ^"1 : 3410 (OH), 1720 (C=CF ) , 1675 (3-C0), 1625 (Δ ⁴ ) MS (m/z): 336.

According to the above described procedure and starting from the appropriate compound of formula (IV) respectively one can prepare the following products as single isomers, as well as their 17θ(,17β-mixtures: 6-difluoromethylenandrost-4-en-17o(-ol-3-one; 6-difluoromethylenandrosta-1,4-dien-17o^-ol-3-one; and 6-difluoromethylenandrosta-1,4-dien-17β-ol-3-one.

Example 4

A solution of 3 ^β , 17B-diacetoxy-6-difluoromethylene-s - fluoroandrostane (442 mg, 1 mmol) in methanol (15 ml) con¬ taining potassium hydroxide (336 mg, 6 mmol) is refluxed for 4 h. The reaction mixture Is concentrated under vacuum, diluted with water and extracted with ethyl acetate. The combined organic layers are washed with saline solution, dried over magnesium sulfate and evaporated under reduced pressure. The residue is crystallized from acetone-hexane giving pure 6-difluoromethylene-5θ(-fluoroandrostane-3, 17- diol (323 g, 90 % yield). calcd: C 67.0-2 H 8.15 F 15.90 found: C 67.10 H 8.05 F 15.81 MS (m/z): 358. IR cm ^"1 : 3350 (OH), 1720 (C=CF )

Example 5

A solution of 3β, 17β-diacetoxy-5β(-fluoroandrostan-6-one (408 g, 1 mmol) and tributylphosphine (344 mg, 1.7 mmol) in N-methyl-2-pyrrolidone (2 ml) is heated to 180°C. To this solution is added dropwise during 40 min a solution of sodium chlorodifluoroacetate (401 mg, 3.3 mmol) in N-methyl-2-pyrrolidone (6 ml). The reaction mixture is dissolved in benzene after cooling and the solution sub¬ mitted to column chromatography. Gradient elution with benzene-ether mixture affords besides starting material the desired 3 ^β , 17 ^β -diacetoxy-6-difluoromethylene-5D\ ^' -fluo- roandrostane (133 mg, 30 % yield).

C H F 0 ₄ calcd: C 65.14 H 7.52 F 12.88 found: C 65.05 H 7.44 F 12.75 MS (m/z): 442.

IR cm ^-1 : 1740 (-0C0CH ), 1725 (C=CF ). t__

Example 6

To a solution of 3B, 17β-diacetoxy-5( ~fluoroandrostan-6β- ol (408 mg, 1 mmol) in acetone (20 ml) is added portion- wise Jones reagent (1 ml) under cooling at 10-15°C. The stirring is continued for Y _z h at 10-15°C and another V _z h at 20-25°C. After addition of methanol (1 ml), the green mixture is filtered and the filtrate carefully diluted with water In order to precipitate the raw product. This is filtered off and chromatographed on silica gel using gradient elution with benzene-ether mixtures. Thus pure 3B, 17β-diacetoxy-5fl(.-fluoroandrostan-3-one is obtained (327 mg, 80 % yield) .

C H F0 _r calcd: C 67.62 H 8.14 F 4.65 23 33 5 found: C 67.45 H 8.05 F 4.57 MS (m/z): 408.

IR cm ^" : 1735 (acetate), 1705 (6-ketone).

Example 7

A solution of 3β, 17B-diacetoxy-5, 6B-epoxyandrostane (389 mg, 1 mmol) in benzene (20 ml) is treated with boron tri- fluoride etherate (227 mg, 1.6 mmol) at 20-25°C for h. The solution is washed with water, dried over potassium carbonate and the solvent evaporated under vacuum. The residue is chromatographed as usually to give pure 3β,17B- diacetoxy-50(-fluoro-androstan-6B-ol (308 mg, 75 % yield).

C„„H F0,. calcd: C 67.29 H 8.59 F 4.63 23 35 5 found: C 67.15 H 8.46 F 4.55

MS (m/z): 408 IR cm : 3350 (hydroxy), 1735 (acetate)

Example 8

A solution of 17B-diacetoxyandrostan-6B-ol (471 mg, 1 mmol) in dichloromethane (25 ml) containing basic alumina (3 g) is stirred for 2 h at 20-25°C. The alumina is filtered off, the residue washed with dichloro¬ methane and the combined filtrate evaporated under vacuum. The residue is crystallized from dichloromethane-acetone to afford pure 3B, 17β-diacetoxy-5,6β-epoxyandrostane (233 mg, 60 % yield). C H O calcd: C 70.74 H 8.78 found: C 70.55 H 8-65

MS (m/z): 390

_ι IR cm : 1735 (acetate).

Example 9

A solution of 3B, 17β-diacetoxyandrost-5-ene (379 mg, 1 mmol) in dioxan (5 ml) is treated with N-bromoacetamide (193 mg _f 1.4 mmol), perchloric acid 70 % (0.1 ml) and water (1 ml) for Y _z h at 20-25°C. The mixture is diluted with water and then extracted with benzene. The organic layer is separated, washed with water, dried over sodium sulfate and evaporated in vacuum. The residue is crystal¬ lized from chloroform-hexane to give pure 5o(-bromo-3B, 17B- diacetoxy-androstan-6β-ol (306 mg, 65 % yield).

C_H _c Br0 _r calcd: C 58.60 H 7.48 Br 16.95 <-- b 5 found: C 58.30 H 7.35 Br 16.60 MS (m/z): 471 IR cm ^" : 3350 (OH), 1735 (acetate).

Example 10

Tablets each weighing 0.150 g and containing 25 mg of the active substance, were manufactured as follows:

Composition (for 10,000 tablets):

6-difluorome hylenandrost-4-ene-3, 17-dione 250 g Lactose 800 g

Corn starch 415 g

Talc powder 30 g

Magnesium stearate 5 g

The 6-difluoromethylenandrost-4-ene-3, 17-dione, the lact¬ ose and half the corn starch were mixed; the mixture was then forced through a sieve of 0.5 mm mesh size. Corn starch (10 g) was suspended in warm water (90 ml) and the resulting paste was used to granulate the powder. The granulate was dried, comminuted on a sieve of 1.4 mm mesh size, then the remaining quantity of starch, talc and magnesium stearate was added, carefully mixed and pro¬ cessed into tablets.

Example 11

Capsules, each dosed at 0.200 g and containing 20 mg of the active substance were prepared.

Composition for 500 capsules:

6-difluoromethylenandrost-4-en-17β-ol-3-one 10 g Lactose 80 g

Corn starch 5 g

Magnesium stearate 5 g

This formulation was encapsulated in two-piece hard ge¬ latin capsules and dosed at 0.200 g for each capsule.