WO1995001366A1

WO1995001366A1 - Fluorinated 6-methylenandrosta-1,4-dien-3-one derivatives and process for their preparation

Info

Publication number: WO1995001366A1
Application number: PCT/EP1994/001993
Authority: WO
Inventors: Franco Buzzetti; Antonio Longo; Enrico Di Salle
Original assignee: Farmitalia Carlo Erba SRL; Carlo Erba SpA; Pharmacia SpA
Current assignee: Pfizer Italia SRL
Priority date: 1993-06-29
Filing date: 1994-06-06
Publication date: 1995-01-12
Anticipated expiration: 1995-12-29
Also published as: GB9313420D0; EP0656901A1; JPH08500609A

Abstract

The present invention relates to compounds of formula (I) wherein A is a ⊃C=O, ⊃CHvvvOH or ⊃CHvvvOR4 group, in which R4 is an acyl group; one or two of R?1, R2 and R3¿ is fluorine and the others are hydrogens; provided that when R2 is fluorine one of R?1 and R3¿ is also fluorine. The compounds of the invention are useful as aromatase inhibitors.

Description

FC 61 3

Fluorinated 6-methylenandrosta-l .4-dien-3-one derivatives and process for their preparation

The present invention relates to new fluorinated 6- methylenandrosta-l ,4-dien-3-one derivatives, 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 metabolites 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, emdometrial and ovarian carcinomas.

Estrogens are also involved in the pathogenesis of benign prostatic hyperplasia.

Endogenous estrogens are ultimately formed from either androstenedione 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 estrogens, it has been envisaged that an effective inhibition of the aromatase, resulting from compounds able to interact with the aromatizing steps, may have useful application for controlling the amount of circulating estrogens, estrogen-dependent processes in reproduction, and estrogen-dependent tumours.

Known steroidal substances which have been reported to be endowed with an aromatase-inhibiting action are, for example, Δ'-testololactone (U.S.Pat. 2,744,120), 4- hydroxyandrost-4-ene-3 , 17-dione and esters thereof (see, for example, U.S.Pat. 4,235,893), 10-( 1 ,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-thioandrostene derivatives (Europ.Pat.Appl. 100,566), androsta-4,6- diene-3, 17-dione , androsta- 1 ,4 ,6-triene-3 , 17-dione (UK.Pat.Appl . 2,100,601A), androsta-1 ,4-diene-3 , 17-dione (Cancer Res. (Suppl . ) 4 , 3327 (1982).

Non fluorinated 6-methylenandrosta-l ,4-diene-3-one derivatives are disclosed in U.S.Pat. 4,822,528; whilst otherwise halogen substituted 6-methylenandrosta-l ,4- diene-3-one derivatives are disclosed in U.S.Pat. 4,808,616, U.S.Pat. 4,824,830, U.S.Pat. 4,873,233 and our coτ>eiic.ng U.K.Pat.Appl . 9201224.4. The present invention provides new compounds having the following general formula (I)

wherein

A is a >c=0, >CHvWOH or >CHW0R⁴ group, in which R⁴ is an acyl group; one or two of R¹, R² and R³ is fluorine and the others are hydrogens, provided that when R² is fluorine one of R¹ and

R³ is also fluorine.

The invention includes within its scope all the possible isomers, stereoisomers and their mixtures, and the metabolites and the metabolic precursors or bioprecursors of the compound of formula (I) . In the formulae of the specification the heavy solid lines ( -^ ) indicate that a substituent is in the β-configuration, i.e. above the plane of the ring, whereas a dotted line ( ) indicates that a substituent is in the α-configuration, i.e. beneath the plane of the ring, and a wavy line ( ΛV) indicates that a substituent may be either in the α- configuration or in the β-configuration or both, i.e. a mixture thereof. In particular when in the compound of formula (I) A is

>CH w OH or >CH the υH and OR⁴ substituent respectively may be either in the α- or in the β- configuration or both, i.e. a mixture thereof. Analogously, when R is a fluorine substituent the fluorine may be either in the E- or in the Z- configuration or both, i.e. a mixture thereof.

Hence a compound of the invention herein specifically mentioned, without any indication of its stereochemistry, is intended to represent all its possible isomers and mixtures thereof. An acyl group may be a residue of any physiologically tolerable acid. Preferred examples of said acids are the C.-C. alkanoic ones; in particular acetic, propionic and butyric acids. The acyl group is therefore preferably a C_j-C_j alkanoyl group, more preferably a C,-C_j alkanoyl group, such as acetyl , propionyl or butyryl.

As stated above, the present invention also includes within 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 formula (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

A is a >C=0, >CH^0H or >CH--------fOCOCH_j group; and one or two of R , R and R is fluorine and the others are hydrogens, provided that when R is fluorine one of R and

R is also fluorine.

Examples of specific compounds of the invention are the following compounds:

2-fluoro-6-methylenandrosta-l,4-diene-3,17-dione;

2-fluoro-6-methylenandrosta-l,4-dien-17β-ol-3-one;

17β-acetoxy-2-f luoro-6-methylenandrosta-l , 4-dien-3-one ;

6-f luoromethylenandrosta-1 ,4-diene-3, 17-dione; 6-f luoromethylenandrosta-1 ,4-dien-17β-ol-3-one;

17β-acetoxy-6-fluoromethylenandrosta-l,4-dien-3-one;

4-f luoro-6-f luoromethylenandrosta-1 , 4-diene-3 , 17-dione ;

4-fluoro-6-fluoromethylenandrosta-l,4-dien-17β-ol-3-one;

17β-acetoxy-4-f luoro-6-f luoromethylenandrosta-1 ,4-dien-3-one; 2,4-dif luoro-6-methylenandrosta-l,4-diene-3, 17-dione;

2,4-difluoro-6-methylenandrosta-l ,4-diene-17β-ol-3-one;

17β-acetoxy-2,4-dif luoro-6-methylenandrosta-l ,4-dien-3-one;

2-f luoro-6-f luoromethylenandrosta-l,4-diene-3,17-dione;

2-f luoro-6-f luoromethylenandrosta-l,4-dien-17β-ol-3-one; and 17β-acetoxy-2-fluoro-6-fluoromethylenandrosta-l,4-dien-3-one.

The compounds of the invention can be obtained by a process comprising:

(a) epoxide cleavage with hydrogen fluoride of a compound of formula (II)

wherein A is a defined above, so obtaining a compound of formula (I) wherein A is as defined above, R is fluorine and R and R are hydrogen; or (b) dehydrogenation of a compound of formula (III)

wherein A is as defined above, so obtaining a compound of formula (I) wherein A is as defined above, R³ is fluorine and R and R are hydrogen; or (c) epoxide cleavage with hydrogen fluoride of a compound of formula (IV)

wherein A is as defined above, so obtaining a compound of formula (I) wherein A is as defined above, R and R are fluorine and R is hydrogen; or (d) epoxide cleavage with hydrogen fluoride of a compound of formula (V)

wherein A is as defined above, so obtaining a compound of formula (I) wherein A is as defined above, R and R are fluorine and R is hydrogen; or (e) epoxide cleavage with hydrogen fluoride of a compound of formula (VI)

wherein A is as defined above, so obtaining a compound of formula (I) wherein R and R are fluorine and R is hydrogen; or (f) selective reduction of a compound of formula (IA) - 8 -

wherein R , R and R are as defined above, thus obtaining a compound of formula (I) in which R , R and R are as defined above and A is a >CH-wOH group; or (g) acylation of a compound of formula (IB)

wherein R , R and R are as defined above, thus obtaining a compound of formula ( I ) in which R , R and R are as defined above and A is a >CH--w^χθR group wherein R is an acyl group; or

(h) oxidation of a compound of formula (IB) wherein R ,

R and R are as defined above, thus obtaining a compound of formula (I) in which R , R and R are as defined above and A is a >C=0 group and/or if desired, converting a compound of formula (I) into another compound of formula (I); and/or, if desired, separating a mixture of isoraers of a compound of formula (I) into the single isomers.

The epoxide cleavage with hydrogen fluoride of a compound of formulae (II), (IV), (V) or (VI) according, respectively, to the process steps (a), (c) (d) and (e) in order to obtain an unstable fluorohydrin intermediate, which dehydrates under acidic conditions to give the desired 2-fluoro-Δ -or 4-fluoro-Δ -compound respectively, may be performed according to known procedures. Preferably it is carried out by reaction with anhydrous hydrofluoric acid in an inert organic solvent such as tetrahydrofuran, chloroform or mixtures thereof at temperatures ranging from about -78^*C to room temperature. In the case there is no simultaneous dehydration it can be induced e.g. by catalysis with cone, hydrochloric acid in hot ethanol solution.

The dehydrogenation of a compound of formula (III) according to the process step (b) may be performed according to known methods, e.g. by treatment with DDQ as described by Walker and Hiebert in Chem. Rev. 6_., 156 (1967). Alternatively it can be performed by treatment with enzene seleninic anhydride as described by Barton et al. in Chem. Commun. 1978, 130. In the latter case the reaction is carried out in an inert organic solvent, such as chlorobenzene or carbon tetrachloride , at a temperature ranging from about 60' to 120^*C.

The selective reduction of a compound of formula (IA) according to process (f) may be carried out by well known methods, for example as described by Djerassi in Steroid Reactions (Holden-Day Inc. 1963) or by Fried in Organic Reactions in Steroid Chemistry (1972). Preferably the reduction is carried out with complexed metal hydrides, in particular with sodium borohydride in an inert organic solvent, preferably in methanol solution at temperatures ranging from about 0^*C to 50^*C.

The acylation of a compound of formula (I) according to process step (g) can be performed, e.g., 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"C to about 50^*C. Preferably the acylation is carried out by reaction with the respective anhydride in the presence of an organic base such as pyridine.

The oxidation of a compound of formula (I) according to process step (h) can be performed according to known methods, e.g. by treatment with Jones reagent as described by Fieser and Fieser in Reagents for Organic Synthesis i,142 (Ed. 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 a temperature ranging from about -20^*C to about 30"C, with the Jones reagent.

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.

The conversion of a compound of formula (I) into another compound of formula (I) includes for example the conversion of a 17β-hydroxy derivative of a compound of formula (I) into the corresponding 17α-hydroxy derivative which may be carried out by basic catalysis, e.g. with 0.1N sodium hydroxide in an aliphatic alcohol, e.g. ethanol.

Others examples of conversions of a compound of formula (I) into another compound of formula (I) are: the reduction of a compound of formula (I), wherein R¹ , R- and R are as defined above and A is >C=0 group, into a corresponding compound of formula (I) wher . in A is >CH'vwOH group, which reaction may be carried out by the method reported in process step (f); the acylation of a compound of formula (I), wherein R^ , R and R^J are as defined above and A is >CH^OH group, into a corresponding compound of formula (I), wherein A is

group, in which R is an acyl group. This reaction may be carried out by the method reported in process step (g); the oxidation of a compound of formula (I), wherein R , R and R are as defined above and A is >CH-*OH group, into a corresponding compound of formula (I), wherein A is a >C=0 group, which reaction may be carried out by the method reported in process step (h).

A compound of formula (II) can be obtained by epoxidation of a compound of formula (VII)

wherein A is as defined above. The epoxidation may be carried out by treatment with a suitable oxidizing agent, e.g. 36% H-O, in hydroalcoholic alkali hydroxide solution, preferably KOH or NaOH in methanol, at a temperature ranging from about 0^* to 30^*C for reaction times lasting from 2h to several days. The compounds of formula (VII) are known or may be obtained by known methods from known compounds (see e.g. U.S. Pat. 4,808,816 and U.S. Pat. 4,873,233)

A compound of formula (III) can be obtained by fluorination of a compound of formula (VIII)

whe

ulfur trifluoride (DAST) e.g. according to the method of W.J.

Middleton (J.Org. Chem. 1975. 40. 574). Thus the reaction of the aldehyde with DAST is carried out without or with a solvent such as dichloromethane or trichlorofluoro- methane or mixtures thereof at temperatures ranging from about 0' to about 80^*C.

The compounds of formula (VIII) are known or may be obtained by known methods from known compounds (see e.g. D. Burn et al . in Tetrahedron 1964. 20. 597-609).

A compound of formula (IV) can be obtained by dehydrogenation of a compound of formula (IX)

wherein A is as defined above. The dehydrogenation may be performed according to known methods, e.g. as described at process step (b).

A compound of formula (IX) can be obtained by alkaline epoxidation of a compound of formula (III) wherein A is as defined above. The same method can be applied as that described above for the epoxidation of compound (VII).

A compound of formula (V) can be obtained by alkaline epoxidation of a compound of formula (X)

wherein A is as defined above. The epoxidation may be carried out as described above for the epoxidation of compound (VII).

The compounds of formula (X) are known or may be obtained by known methods from a known compound. E.g. they may be obtained according to U.S. Pat. 4,808,816 and U.S. Pat 4,873,233.

A compound of formula (VI) can be obtained by alkaline epoxidation of a compound of formula (IC)

wherein A is as defined above. The alkaline epoxidation may be carried out as described above.

The compounds of formula ( IC) can be prepared as described in process step (b).

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 reactions, according to well known methods in organic 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 placental microsomal fraction as enzyme source. In this test the aromatization rate of androstenedione into estrone was evaluated by incubating (lβ- H) androstenedione (50nM) in the presence of NADPH with the enzyme preparation and by measuring the amount of H, 0 formed during 20 min incubation at 37^*C.

The compounds, incubated at various concentrations, showed a relevant aromatase inhibitory activity. By virtue of their ability to inhibit aromatase and, consequently, to reduce estrogen levels, the compounds of the invention are useful in mammals, including humans, in the treatment and prevention of various estrogen- dependent diseases, 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 estro n-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 ability 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 (LDJ_Q ) of the compounds of the invention in the mouse, determined by single administration 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 tablets, capsules, sugar or film coated tablets, liquid solutions or suspensions; rectally, in the form of suppositories, parenterally, e.g. intramuscularly, or by intravenous injection or infusion. The dosage depends on the age, weight, conditions of the patient and administration route; for example, the dosage 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 comprising a compound of the invention in association with a pharmaceutically acceptable excipient (which can be a carrier or diluent). The pharmaceutical compositions containing the compounds of the invention are usually prepared following conventional 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; lubricants, e.g. silica, talc, stearic acid, magnesium or calcium stearate, and/or polyethylene glycols; binding agents, e.g. starches, arabic gums, gelatin, methylcellulose, carboxymethylcellulose or polyvinyl pyrrolidone; disaggregating agents, e.g. a starch, alginic acid, alginates 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 pharmaceutical 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 dispersion for oral administration may be e.g. syrups, emulsions and suspensions. The syrups may contain as carrier, for example, saccharose or saccharose with glycerine and/or mannitol and/or sorbitol. The suspensions and the emulsions may contain as carrier, for example, a natural gum, agar, sodium alginate, pectin, methylcellulose, carboxymethylcellulose, or polyvinyl alcohol. The suspensions or solutions for intramuscular injections may contain, together with the active compound, a pharmaceutically 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 following examples illustrate but do not limit the invention:

Example 1

2-fluoro-6-methylenandrosta-l ,4-diene-3, 17-dione.

To a solution of anhydrous hydrogen fluoride (7.00 g, 350 mmol) in tetrahydrofuran (15 ml) and chloroform (5 ml) contained in a screw-capped polyethylene bottle chilled to about -60^*C was added a solution of 1 ,2α-epoxy-6- methylen-androst-4-ene-3 , 17-dione (3.124 g, 10 mmol) in chloroform (25 ml) likewise chilled to about -60^*C. The hydrogen fluoride-tetrahydrofuran reagent was immersed in an acetone-dry ice bath while the steroid was added. Additional chloroform (5 ml) was used to aid in the transfer of the epoxide. The reaction mixture was removed from the acetone-dry ice bath and subsequently maintained at -30^*C for 4 h and then added at a suitable rate to a well agitated mixture of an aqueous solution of potassium carbonate, chloroform and ice. The weakly alkaline aqueous layer was separated and twice back- extracted with chloroform. The combined organic layers were washed with water, dried and evaporated to dryness. The residue was submitted to flash chromatography with ethyl acetate/ethanol 1-2% to give pure title compound in 75% yield. ^C20^H2J°2 calculated: C 81.32 H 7.85 F 6.04 found : C 81.21 H 7.75 F 6,01

MS m/z 295

IR cm^"1: 3070 (C=CH₂), 1725 (17-keto), 1650 (3-keto),

1610 (C=C). According to the above described procedure, the following compounds can be prepared:

2-fluoro-6-methylenandrosta-l , 4-dien-l7β-ol-3-one; 17^β-acetoxy-2-fluoro-6-methylenandrosta-l,4-dien-3-one. NMR S ppm (CDCl_j) : 0.94 (s, 3H, H-18) , 1.22 (s, 3H,H-19), 2.13 (ddd, J=9.1, 9.1, 19.3 Hz, IH, H-16α) , 2.50(dd, J=8.8, 19.3 Hz, IH, H-160) , 2.64 (m, IH, H-eq) 5.04, 5.08 (two m, 2H, C=CH₂) , 6.21(d, J=7.0 Hz, IH, H-4), 6.21(d, J=14.1 Hz, IH, H-l) .

Example 2

6-fluoromethylenandrosta-1 ,4-diene-3 , 17-dione.

A solution of 6-fluoromethylenandrost-4-ene-3, 17-dione (3.16 g, 10 mmol) and benzene seleninic anhydride (3.60 g, 10 mmol) in chlorobenzene (300 ml) was heated for 1 h at 90-100^*C. Then the solvent was removed in vacuum and the residue chromatographed on silica gel using hexane/ethyl acetate 1:1 as eluant to give pure title compound in about 60% yield. C₂₀H₂₃FO₂ calculated: C 76.41 H 7.37 F 6.04 found : C 76.35 H 7.31 F 5.95 MS m/z 314

IR cm^"1: 3070 (C=CHF), 1730 (17-keto), 1650 (3-keto), 1610 (C=C). According to the above described procedure, the following compounds can be prepared:

6-fluoromethylenandrosta-1 ,4-dien-17β-ol-3-one; and 17β-acetoxy-6-fluoromethylenandrosta-1 ,4-die -3-one.

Example 3

4-fluoro-6-fluoromethylenandrosta-l,4-diene-3,17-dione.

To a solution of anhydrous hydrogen fluoride (7.00 g, 350 mmol) in tetrahydrofuran (15 ml) and chloroform (5 ml) contained in a screw-capped polyethylene bottle chilled to about -60°C was added a solution of 4,5-epoxy-6- fluoromethylenandrost-l-ene-3,17-dione (3.304 g, 10 mmol) in chloroform (25 ml) likewise chilled to about -60°C.

The hydrogen fluoride solution was immersed in an acetone-dry ice bath while the steroid was added.

Additional chloroform (5 ml) was added to complete the transfer of the epoxide.

Subsequently the reaction mixture was maintained at -30°C for 4 h. The workup and purification was carried out as described in example 1. Yield 70%.

C₂₀H_;5jF₂O₂ calculated: C 72.27 H 6.67 F 11.43 found: C 72.15 H 6.56 F 11.35

MS m/z 332.

IR cm'¹ : 3050 (C=CHF) , 1730 ( 17-keto) , 1650 ( 3-keto) , 1600 (C=C)

According to the above described procedure the following compound r.: can be prepared :

4-f luoro-6-f luoromethylenandrosta-l , 4-dien-17β-ol-3-one; and

17β-acetoxy-4-f luoro-6-f luoromethylenandrosta-1 , 4-dien-3-one . Example 4

2 ,4-difluoro-6-methylenandrosta-l ,4-diene-3 , 17-dione

To a solution of anhydrous hydrogen fluoride (7.00 g, 350 mmol) in tetrahydrofuran (15 ml) and chloroform (5 ml) contained in a screw-capped polyethylene bottle chilled to -60"C was added a solution of 1 ,2-epoxy-4-fluoro-6- methylenandrost-4-ene-3, 17-dione (3.304 g, 10 mmol) in chloroform (25 ml) likewise chilled to -60^*C. The hydrogen fluoride solution was immersed in an acetone -dry ice bath during the addition of the steroid.

Then the reaction mixture was maintained for 3 h at about -30^*C. Workup and purification was carried out as described in example 1. Yield 65% ^C20^H22^F2°2 calculated: C 72.27 H 6.67 F 11.43 found : C 72.05 H 6.41 F 11.31

MS m/z 332 IR cm^"1: 3040 (C=CH₂), 1735 (17-keto), 1670 (3-keto), 1610

(C=C). By proceeding analogously the following compounds can be prepared:

2,4-difluoro-6-methylenandrosta-l,4-dien-17β-ol-3-one; and 17β-acetoxy-2,4-difluoro-6-methylenandrosta-l,4-dien-3-one. Example 5

2-f luoro-6-f luoromethylenandrosta-1 , 4-diene-3 , 17-dione

To a solution of anhydrous hydrogen fluoride (7.00 g, 350 mmol) in tetrahydrof uran (15 ml) and chloroform (5 ml) contained in a screw-capped polyethylene bottle chilled to -60^*C was added a solution of l,2-epoxy-6- fluoromethylenandrost-4-ene-3, 17-dione (3,304 , 10 mmol) in chloroform (25 ml) likewise chilled to -60^*C. The hydrogen fluoride solution was immersed in an acetone-dry ice bath while the steroid was added. Then the reaction mixture was stirred for 4 h at about -30^*C. Workup and purification was performed as described before. Yield about 60%. C_2(JH₂₂F₂0₂ calculated: C 72.27 H 6.67 F 11.43 found : C 72.15 H 6.63 F 11.21

MS m/z 332

IR cm^'1: 3050, 1735, 1655, 1610.

By proceeding analogously the following compounds can be prepared: 2-fluoro-6-fluoromethylenandrosta-l,4-dien-17β-ol-3-one; and 17β-acetoxy-2-fluoro-6-fluoromethylenandrosta-l,4-dien-3-one. Example 6

2-fluoro-6-methylenandrosta-l ,4-dien-17β-ol-3-one.

To a stirred solution of 2-fluoro-6-methylenandrosta-l ,4- diene-3, 17-dione (3.144 g, 10 mmol) in methanol (200 ml) was added sodium borohydride (0.570 g, 15 mmol) over a period of 20 min at 0-5^*C and stirring was continued for 1 h at 0-5^*C. After addition of few drops of acetic acid, the mixture was concentrated under vacuum, diluted with water and then extracted with ethyl acetate. The combined organic phases were washed with saline solution, dried over Na₂SO. and then evaporated in vacuum. The residue was submitted to column chromatography on silica gel. Gradient elution with hexane-ethylacetate mixtures afforded pure title compound in about 70% yield. C₂₀H_2JFO₂ calculated: C 75.92 H 7.96 F 6.00 found : C 75.75 H 7.85 F 5.95

MS m/z 316

IR cm^"1: 3400-3200 (OH), 3050 (C=CH₂), 1655 (3-keto), 1610 (double bonds). According to the above reported procedure, the following compounds can be obtained: 6-fluoromethylenandrosta-l,4-diene-17β-ol-3-one; 4-fluoro-6-f luoromethylenandrosta-l,4-dien-17β-ol-3-one; 2,4-dif luoro-6-methylenandrosta-l,4-dien-17β-ol-3-one; and 2-fluoro-6-fluoromethylenandrosta-l,4-dien-17β-ol-3-one. Example 7

17β-acetoxy-2-fluoro-6-methylenandrosta-l ,4-diene-3-one.

To a cooled solution of 2-fluoro-6-methylenandrosta-l ,4- dien-17β-ol-3-one (3.164 g, 10 mmol) in dry pyridine (5 ml) was added acetic anhydride (4.084 g, 40 mmol) and the mixture maintained at 0-5^*C overnight. The solvent was removed in vacuum, the residue dissolved in dichloromethane, the organic layer washed with water and then evaporated under reduced pressure. The crude product was crystallized from benzene to yield pure title compound in about 80% yield.

^C22^H2T°3^F calculated: C 73.72 H 7.59 F 5.30 found : C 73.55 H 7.51 F 5.25 MS m/z 358 IR cm^"1: 3050 (C=CH₂), 1740 (acotate), 1645 (3-keto), 1610 (double bonds) . By proceeding analogously the following compounds are obtained: 17β-acetoxy-6-fluoromethylenandrosta-l,4-dien-3-one; 17β-acetoxy-4-fluoro-6-fluoromethylenandrosta-l,4-dien-3-one;

17fl-acetoxy-2,4-difluoro-6-methylenandrosta-l,4-dien-3-one; and 17β-acetoxy-2-fluoro-6-fluoromethylenandrosta-1,4-dien-3-one. Example 8

6-fluoromethylenandrosta-1 ,4-diene-3 , 17-dione.

To a solution of 6-fluoromethylenandrosta-1 ,4-dien-17β- ol-3-one (3.164 g, 10 mmol) in acetone (100 ml) was added portionwise Jones reagent (10 ml) under cooling at 0-5'C and the stirring was continued for J h at 0-5^*C. Then isopropanol (10 ml) was added to quench the oxidation and the mixture was extracted with ethyl acetate after dilution with water. The organic phase was washed with bicarbonate solution and water, dried and evaporated under vacuum. The residue was submitted to flash chromatography on silica gel using n-hexane/EtOAc 7:3 as eluant to give pure title compound in about 70% yield. C₂₀H_2JFO₂ calculated: C 76.41 H 7.37 F 6.04 found : C 76.25 H 7.30 F 5.85

MS m/z 314 IR cm^"1: 3070 (C=CHF), 1730 (17-keto), 1650 (3-keto),

1610 (double bonds). According to the above described procedure, the following compounds can be prepared:

2-fluoro-6-methylenandrosta-l ,4-diene-3, 17-dione; 4-fluoro-6-fluoromethylenandrosta-1 ,4-diene-3 , 17-dione; 2 ,4-difluoro-6-methylenandrosta-l ,4-diene-3 , 17-dione; and 2-fluoro-6-fluoromethylenandrosta-1 ,4-diene-3 , 17-dione. Example 9

1 , 2α-epoxy-6-methylenandrosta-l ,4-diene-3 , 17-dione

6-methylenandrosta-l ,4-diene-3 , 17-dione ( 2.964 , 10 mmol ) was dissolved in methanol (200 ml) and the resulting solution cooled to O'C. Thereupon ice cold 36% hydrogen peroxide (20 ml) and 2% sodium hydroxide (10 ml) were added. The mixture was stirred for about 24 h at O'C and then poured into ice water. The product was filtered off, washed with water and then dried to give almost pure title compound in about 50% yield (1.560 g). C₂₀H₂₄O_j calculated: C 76.89 H 7.74 found : C 76.85 H 7.65 MS m/z 312 IR cm^"1: 3060 (C=CH₂), 1740 (17-keto), 1715 (3-keto), 1250 (epoxide).

Example 10

6-fluoromethylenandrosta-4-ene-3 , 17-dione

Diethylaminosulfur trifluoride (DAST, 6.45 g, 40 mmol) was added at room temperature to a stirred solution of 6- formyl-3-methoxyandrosta-3, 5-dien-17-one (3.285 g, 10 mmol) in dry dichloromethane (50 ml). The solution was stirred for 44 h, diluted with dichloromethane, poured onto crushed ice, and the organic layer was collected. The aqueous layer was further extracted twice with dichloromethane. The combined organic phases were washed with 5% NaHCO, solution and water, dried over Na.SO. and evaporated to dryness. The residue was flash chromato- graphed on silica gel with benzene/ether 4: 1 as eluant to give pure title compound in about 60% yield. C₂₀H₂₅FO₂ calculated: C 75.92 H 7.96 F 6.00 found : C 75.85 H 7.86 F 5.91 MS m/z 316

IR cm^"1: 3070 (C=CHF), 1725 (17-keto), 1670 (3-keto), 1620 (C=C).

Example 11

4 , 5-epoxy-6-fluoromethylenandrost-l-ene-3, 17-dione

6-fluoromethylenandros -4-ene-3, 17-dione (3.164 g, 10 mmol) was dissolved in methanol (200 ml) and the resulting solution cooled to O'C. Thereupon ice cold 36% hydrogen peroxide (10 ml) were added. The mixture was stirred for about 24 h at O'C and then poured into ice water. The product was filtered off, washed with water and then dried to give 4 ,5-epoxy-6-fluoromethylen- androstane-3,17-dione in about 50% yield (1.662 g).

A solution of 4,5-epoxy-6-fluoromethylenandrostane-3, 17- dione (1.662 g, 5 mmol) and benzeneseleninic anhydride (1.801 g, 5 mmol) in chlorobenzene (150 ml) was heated for 4h at 90-100^*C. Then the solvent was removed in vacuum and the residue chromatographed on silica gel with benzene/ethyl ether 10% to give pure title compound in about 40% yield.

C₂₀H_2JFO_j calculated: C 72.71 H 7.02 F 5.75 found : C 72.65 H 6.95 F 5.66 MS m/z 330

IR cm^"1: 3060 (C=CHF), 1740 (17-keto), 1715 (3-keto), 1250 (epoxide). Example 12

1 , 2α-epoxy-4-fluoro-6-methylenandrost-4-ene-3 , 17-dione

4-fluoro-6-methylenandrosta-l ,4-diene-3 , 17-dione ( 3.144 g, 10 mmol) was dissolved in methanol (20 ml) and the resulting solution cooled to O'C. Thereupon ice cold 36% hydrogen peroxide (20 ml) and 2% sodium hydroxide (10 ml) were added. The mixture was stirred for about 24 h at O'C and then poured into ice water. The product was filtered off, washed with water and then dried to give almost pure title compound in about 60% yield.

C₂₀H_2JFO_j calculated: C 72.71 H 7.02 F 5.75 found : C 72.63 H 6.65 F 5.65

MS m/z 330 IR cm^"1: 3050 (C=CH₂), 1735 (17-keto), 1710 (3-keto), 1240 (epoxide).

Example 13

1 ,2α-epoxy-6-fluoromethylenandrost-4-ene-3 , 17-dione.

6-fluoromethylenandrost-4-ene-3, 17-dione (3.144 g, 10 mmol) was dissolved in methanol (20 ml) and the resulting solution cooled to O'C. Thereupon ice cold 36% H_jO_j (20 ml) and 2% NaOH (10 ml) was added. The mixture was stirred for about 24 h at O'C and then poured into ice water. The product was filtered off, washed with water and then dried to give almost pure title compound in about 50% yield.

C₂₀H_2jFO₃ calculated: C 72.71 H 7.02 F 5.75 found : C 72.68 H 6.85 F 5.55 MS m/z 330.

Example 14

Tablets each weighing 0.150 g and containing 25 mg of the active substance, can be manufactured as follows: composition (for 10,000 tablets):

2-fluoro-6-methylenandrosta-l ,4-diene-3, 17-dione 250 g

Lactose 800 g

Corn starch 415 g

Talc powder 30 g

Magnesium stearate 5 g

The 2-fluoro-6-methylenandrosta-l ,4-diene-3, 17-dione, the lactose and half of the corn starch are mixed; the mixture is then forced through a sieve of 0.5 mm mesh size. Corn starch (10 g) is suspended in warm water (90 ml) and the resulting paste is used to granulate the powder. The granulate is dried, comminuted on a sieve of 1.4 mm mesh size, then the remaining quantity of starch, talc and magnesium stearate are added, carefully mixed and processed into tablets. Example 15

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

Composition for 500 capsules:

6-fluoromethylenandrosta-1 ,4-.diene-3 , 17-dione 10 g

Lactose 80 g

Corn starch 5 g

Magnesium stearate 5 g

This formulation is encapsulated in two-piece hard gelatin capsules and dosed at 0.200 g for each capsule.

Claims

A compound of formula ( I )

A is a >C=0, >CH-rwOH or >CH ✓v DR group, in which R is an acyl group; one or two of R , R and R is fluorine and the others are hydrogens; provided that when R is fluorine one of R and R is also fluorine;

A compound of formula (I), according to claim 1 wherein

A is a >C=0, >CH- 0H or CH^IOCOCH_j group; and one or two of R , R and R is fluorine and the others are hydrogens, provided that when R is fluorine, one of R. and R_j is also fluorine;

A compound selected from the group consisting of : 2-fluoro-6-methylenandrosta-l , 4-diene-3, 17-dione; 2-f luoro-6-methylenandrosta-l , 4-dien-17β-ol-3-one ; 17β-acetoxy-2-f luoro-6-methylenandrosta-l , 4-dien-3-one; 6-fluoromethylenandrosta-l , 4-diene-3 , 17-dione; 6-fluoromethylenandrosta-l,4-dien-17β-ol-3-one;

17β-acetoxy-6-fluoromethylenandrosta-l,4-dien-3-one;

4-fluoro-6-fluoromethylenandrosta-l,4-diene-3,17-dione;

4-fluoro-6-fluoromethylenandrosta-l,4-dien-17β-ol-3-one;

17β-acetoxy-4-fluoro-6-fluoromethylenandrosta-l,4-dien-3-one;

2,4-difluoro-6-methylenandrosta-l,4-diene-3,17-dione;

2,4-difluoro-6-methylenandrosta-l,4-diene-17β-ol-3-one;

17β-acetoxy-2 , 4-dif luoro-6-methylenandrosta-l , 4-dien-3-one;

2-f luoro-6-f luoromethylenandrosta-l , 4-diene-3 , 17-dione;

2-f luoro-6-f luoromethylenandrosta-l , 4-dien-17β-ol-3-one; and

17β-acetoxy-2-fluoro-6-fluoromethylenandrosta-l ,4-dien-3-one.

A process for the preparation of a compound of formula ( I ) , according to claim 1 , said process comprising

(a) epoxide cleavage with hydrogen fluoride of a compound of formula (II)

wherein A is as defined in claim 1, so obtaining a compound of formula (I) wherein A is as defined in claim 1 R is fluorine and R and R are hydrogen; or

(b) dehydrogenation of a compound of formula (III)

CHF wherein A is as defined in claim 1, so obtaining a compound of formula (I) wherein A is as defined in claim 1, R is fluorine and R and R are hydrogen; or (c) epoxide cleavage with hydrogen fluoride of a compound of formula (IV)

wherein A is as defined in claim 1 so obtaining a compound of formula (I) wherein A is as defined above, R and R are fluorine and R is hydrogen; or (d) epoxide cleavage with hydrogen fluoride of a compound of formula (V)

wherein A is as defined in claim 1, so obtaining a compound of formula (I) wherein A is as defined in claim 1 , R and R are fluorine and R is hydrogen; or (e) epoxide cleavage with hydrogen fluoride of a compound of formula (VI)

wherein A is as defined in claim 1, so obtaining a compound of formula (I) wherein A is as defined in claim 1, R and R are fluorine and R is hydrogen; or (f) selective reduction of a compound of formula (IA)

wherein R¹ , R and R are as defined in claim 1, thus obtaining a compound of formula (I) in which R , R and R are as defined in claim 1 and A is a >CHvwOH group; or (g) acylation of a compound of formula (IB)

W

1, thus obtaining a compound of formula (I) in which R , R and R are as defined in claim 1 and A is a >CH-» OR wherein R is an acyl group.

(h) oxidation of a compound of formula (IB) wherein R , and R are as defined above, thus obtaining a compound of formula (I) in which R , R and R are as defined above and A is a >C=0 group and/or if desired, converting a compound of formula (I) into another compound of formula (I); and/or, if desired, separating a mixture of isomers of a compound of formula (I) into the single isomers.

5. A pharmaceutical composition comprising, as an active principle, a compound of formula (I) according to claim 1 , and a suitable carrier and/or diluent.

6. A compound of formula (I), according to claim 1, for use in a method of treatment of the human or animal body by therapy.

7. A compound of formula (I) according to claim 1, for use as an aromatase inhibitor.

8. Use of a compound of formula (I) as defined in claim 1 , in the preparation of a medicament for use as an aromatase inhibitor.