IE862906L - Producing delta-2-androstenic derivatives - Google Patents

Description

/I 1 ~t I The invention relates to a process for obtaining a A-2-androstene compound.

According to the invention there is provided a process for obtaining a A-2-androstene compound in the pure state from a mixture of A_2(3) and A~3(4)-androstene, characterized in that a mixture of androstenes corresponding to the general formula H in which the dotted line symbolizes a double bond in position 2(3) or in position 3(4) R represents a hydroxyl which is free, esterified by an organic acid having 1 to 10 carbon atoms or etherified by an alkyl or tetrahydropyranyl radical, R' represents hydrogen, a lower alkenyl radical, a lower alkynyl radical, a lower alkyl radical, a phenyl radical or a cycloalkyl radical, or R and R' together form the oxygen of a ketone function, and the wavy line indicates an a or R orientation, is subjected to the action of a sulphonating agent in the pure form or in an inert solvent, if appropriate in the presence of a dehydrating agent, to give a A-3-androstenyl-2-sulphonic acid of the general formula II in which R and R' have the meanings given above and the non-transformed, pure A-2(3)-androstene derivative of the general formula IV in which the substituents R and R' are defined as above, is obtained.

The preparation of these derivatives is already known and is carried out according to the processes described, mainly either by elimination of tosylate in the 3-position of the corresponding steroid (United States of America Patent 3 098 851) or by pyrolysis of a 3-spiro-3-diazirino steroid (French Patent 1 487 671), but the derivatives obtained by these techniques always contain a significant amount of the A-3-androstene isomer. A process for the purification of 17-oxo-5a-androst-2-ene also exists, which is described by the Applicant (in French Patent Application No. 74-43 397 and comprises oxidizing the A-3-isomer with Jones reagent (chromic anhydride in sulphuric acid solution), the degradation products subsequently being eliminated by 5 chromatography over silica in a benzene medium. Although this process is attractive, it nevertheless has major disadvantages, that is to say, its too low a yield, its too long an execution time, if only because of the chromatography, and finally the use of large amounts of 10 benzene, a particularly toxic solvent.

The present invention is based on the surprising finding that it is possible selectively to sulphonate, in an anhydrous medium, the A-3-androstene isomer to give a strongly acid water-soluble derivative corresponding to the 15 general formula II in which the substituents R and R' have the meanings given above.

This derivative is then easily removed by anion exchange 20 resins in an alcoholic medium or simply by pouring the reaction mixture into water, an operation which causes crystallization of the non-trans formed insoluble A-2-steroid and dissolving of the sulphonated A-3-steroid. After filtration, washing with water and drying, the pure A-2-25 steroid is obtained. Sulphonation with sulphuric acid, in the pure form or in solution, is carried out in an inert mi H solvent, such as, for example, acetic acid, methylene chloride, chloroform or dioxane, in the presence of a dehydrating agent, such as an alkylcarboxylic anhydride, such as acetic anhydride or propionic anhydride. The 5 temperature of the reaction mixture can vary from -5°C to +5°C and the reaction time from a few minutes to several days, depending on the operating conditions.

The structural analysis of the purified steroid was carried out by spectrophotometry in the infra-red and by proton 10 nuclear magnetic resonance. The olefinic protons in C2 and C3 are in the form of a broad singlet at 334 Hz (width at mid-height 5 Hz), whereas for the A-3-androstene derivatives, the olefinic protons appear in the form of 4 peaks between 312 and 348 Hz.

The quantitative analysis of the A-3-androstene isomer was carried out by HPLC after oxidation by chromic anhydride (Cr03) into the a-conjugated ketone, which is detected at 240 nanometres. This technique, which is sensitive and accurate, has shown, by the examples which follow, that the 20 amount of A-3-isomer in the purified steroids is less than 1%.

The purity controls were carried out by thin layer chromatography in the solvent system: toluene 75 ml - ethyl acetate 25 ml and development with an ethanolic solution of 25 20% v/v sulphuric acid and heating for 1 minute at 110°C.

The invention also relates to the A-3-androstenyl-2-sulphonic acids of the general formula II formed in the course of execution of the process according to the invention.

EXAMPLE 1 17-Oxo-5a-androst-2-ene g impure 17-oxo-5a-androstene containing 90% A-2-isomer and 10% A-3-isomer are dissolved in 20ml solvent mixture: 5 methylene chloride 50 ml - acetic anhydride 50 ml. The temperature is kept at 8°C with the aid of an ice-bath, and 20 ml reagent prepared by adding 0.6 ml concentrated sulphuric acid to 20 ml of the above solvent mixture are added in the course of 30 minutes, while stirring. The 10 reaction mixture is poured quickly into 1 litre water and stirred at room temperature for 4 hours. It is filtered and the crystals are washed with a large quantity of water and dried for 4 hours in vacuo at 70°C. 8 g 17-oxo-5a-androst-2-ene are obtained. • weight yield • theoretical yield • TLC • IR spectrum • NMR spectrum • HPLC analysis of A~3 80% 88% single spot conforms to the structure conforms to the structure A-3-isomer not visible 0.4% EXAMPLE 2 17-Oxo-5a-androst-2-ene g impure 17-oxo-5a-androstene containing 86% A-2-isomer 25 and 14% A-3-isomer were dissolved in 40 ml solvent mixture: methylene chloride 30 ml - acetic anhydride 10 ml - acetic acid 60 ml. The temperature is kept at 5°C on an ice-bath, and 40 ml sulphonating reagent prepared by adding 2 ml concentrated sulphuric acid to 30 ml solvent mixture are added, while stirring. The duration of the addition of the reagent was 30 minutes and the reaction mixture is stirred for a further 15 minutes before being poured into 2 litres water. The mixture is stirred for 2 hours and filtered and 5 the residue is washed with a large amount of water and dried for 2 hours in vacuo at 80°C. 17.2 g 17-oxo-5a-androst-2-ene are obtained, • weight yield • theoretical yield 10 • melting point • TLC • IR spectrum • NMR spectrum • HPLC analysis of A-3 86% 99% 101°C single spot conforms to the structure conforms to the structure A-3-isomer not visible 0.8% EXAMPLE 3 17-Oxo-5a-androst-2-ene g impure 17-oxo-5a-androstene containing 80% A-2-isomer and 20% A-3-isomer were dissolved in 50 ml solvent mixture: 20 methylene chloride 75 ml - acetic anhydride 35 ml. The temperature was kept at 5°C with the aid of an ice-bath - 50 ml reagent prepared by adding 1.5 ml sulphuric acid to 48.5 ml solvent mixture were added in the course of 30 minutes.

The reaction mixture was poured quickly into 300 ml 25 anhydrous ethanol, and after being stirred for 2 hours, the solution obtained was passed over a column charged with 50 g DOWEXr AG2 X8 anion exchange resin (in the OH~ form), dehydrated beforehand with anhydrous ethanol. After passage of the solution, the column was washed with 100 ml ethanol and the combined effluents and wash liquors were evaporated to dryness in vacuo. 7.74 g 17-oxo-5a-androst-2-ene are obtained.

EXAMPLE 4 17-oxo-5a-androst-2-ene 10 g impure 17-oxo-5a-androstene containing 83% A-2-isomer and 17% A-3-isomer are dissolved in 20 ml solvent mixture: methylene chloride 90 ml - acetic anhydride 10 ml. The temperature is kept at 0°C on a refrigerator and 20 ml reagent prepared by adding 0.5 ml concentrated sulphuric 20 acid to 20 ml solvent mixture are added quickly, under magnetic stirring. The reaction mixture is stirred at 0°C for 48 hours and poured into 200 ml methanol. After stirring for 2 hours, 20 g DOWEXR AG2 X8 anion exchange resin (in the OH" form), previously dehydrated in methanol 25 for 30 minutes at room temperature, are added. The mixture is filtered, the resin is washed with 50 ml methanol and the combined filtrate and wash liquids are evaporated to dryness.

• IR spectrum 10 • NMR spectrum • theoretical yield • melting point • TLC • HPLC analysis of A~3 • weight yield 77.4% 97% 101.4°C a secondary spot of low intensity conforms to the structure conforms to the structure A-3-isomer not visible 0.7% 7.74 g 17-oxo-5a-androst-2-ene are obtained. • weight yield • theoretical yield • melting point • TLC • IR spectrum • NMR spectrum • HPLC analysis of A~3 77.4% 93% 100.2°C single spot conforms to the structure conforms to the structure A-3-isomer not visible 0.5% EXAMPLE 5 17-Oxo-5a-androst-2-ene g impure 17-oxo-5a-androstene containing 86.5% A-2-isomer and 13.5% A-3-isomer were dissolved in 50 ml dioxane. 10 ml acetic anhydride and 0.8 ml concentrated sulphuric acid are added, while stirring well, and the mixture is stirred at 15 room temperature (about 22°C) for 15 minutes. The reaction mixture is poured into 1 litre water and stirred for 16 hours. It is filtered and the crystals are washed with a large amount of water and dried for 4 hours in vacuo at 80°C. 8.1 g 17-oxo-5a-androst-2-ene are obtained. • weight yield • theoretical yield • melting point • TLC • IR spectrum • NMR spectrum • HPLC analysis of A-3 81% 89.6% 101.8°C single spot conforms to the structure conforms to the structure A-3-isomer not visible 0.1% EXAMPLE 6 17-Oxo-5a-androst-2-ene g impure 17-oxo-5a-androstene containing 86.5% A-2-isomer and 13.5% A-3-isomer are dissolved in 10 ml chloroform. 2 5 ml acetic anhydride and 0.8 ml concentrated sulphuric acid are added, while stirring well, and stirring is maintained at room temperature for 15 minutes. The reaction mixture is poured into 100 ml methanol and, after stirring for 2 hours, 10 g DOWEXR AG2 X8 anion exchange resin (in the OH~ form), 10 dehydrated beforehand with methanol, are added, the mixture is stirred for 30 minutes and filtered, the residue is washed with 20 ml methanol and the combined filtrate and wash liquors are evaporated to dryness in vacuo. 4 g 17-oxo-5a-androst-2- • weight yield • theoretical yield • melting point • TLC • IR spectrum 20 • NMR spectrum • HPLC analysis of A~3 are obtained. 80% 92.5% 102°C single spot conforms to the structure conforms to the structure A-3-isomer not visible 0% EXAMPLE 7 17-Oxo-5ct-androst-2-ene 10 g impure 17-oxo-5a-androstene containing 86.5% A-2-isomer and 13.5% A-3-isomer were dissolved in 50 ml dioxane. 10 ml propionic anhydride and 0.8 ml concentrated sulphuric acid are added, while stirring well, and the mixture is stirred at room temperature for 15 minutes. The reaction mixture is poured into 1 litre water and stirred for 16 hours. It is filtered and the crystals are washed with a large amount of water and dried for 6 hours in vacuo at 65°C. 8.15 g 17-oxo-5a-androst-2-ene are obtained. weight yield theoretical yield melting point TLC IR spectrum NMR spectrum HPLC analysis of /\-3 81.5% 94.2% 101°C single spot conforms to the structure conforms to the structure 0.1% EXAMPLE 8 17fi-Acetoxy-17a-ethinyl-5a-androst-2-ene 10 g impure 17fi-acetoxy-17a-ethinyl-5a-androstene containing 83% /\-2-isomer and 17% /\-3-isomer were dissolved in 50 ml solvent mixture: methylene chloride 75 ml - acetic anhydride 25 ml. 50 ml reagent prepared by addition of 2.8 ml concentrated sulphuric acid to 50 ml solvent mixture are 20 added at room temperature in the course of 30 minutes, while stirring. The reaction mixture is poured into 2 litres water and stirred at room temperature for 16 hours. It is filtered and the crystals are washed with a large amount of water and dried for 4 hours in vacuo at 80°C. 7.12 g 17fi-acetoxy-17a-ethinyl-5a-androst-2-ene are obtained. • weight yield • theoretical yield 71.2% 85.7% • melting point • TLC • IR spectrum • NMR spectrum • HPLC analysis of A~3 126°C single spot conforms to the structure conforms to the structure A-3-isomer not visible 0.7% EXAMPLE 9 17J5-Acetoxy-17cr-ethinyl-5a-androst-2-ene g impure 17fl-acetoxy-17a-ethinyl-5cc-androstene containing 10 86% A-2-isomer and 14% A~3-isomer are dissolved in 100 ml reagent mixture: methylene chloride 88.5 ml - 10 acetic anhydride 10 ml - concentrated sulphuric acid 1.5 ml. The reaction mixture is stirred at room temperature for 30 minutes and poured into 400 ml methanol. After stirring for 15 2 hours, 20 g DOWEXR AG2 XI anion exchange resin (in the OH-form), dehydrated beforehand with methanol, are added and the mixture is stirred for 2 hours. It is filtered, the resin is washed with 200 ml methanol and the combined filtrate and washings are evaporated to dryness in vacuo. 8.5 g 17/3-acetoxy-17a-ethinyl- • weight yield • theoretical yield • melting point • TLC • IR spectrum • NMR spectrum • HPLC analysis of A~3 -androst-2-ene are obtained. 85% 97.7% 126.5°C 1 secondary spot of low intensity conforms to the structure conforms to the structure A-3-isomer not visible 0.7% EXAMPLE 10 17fi-Acetoxy-17a-ethinyl-5a-androst-2-ene g impure 17fi-acetoxy-17a-ethinyl-5a-androstene containing 86% A-2-isomer and 14% A-3-isomer were dissolved in 20 ml methylene chloride. 2 ml acetic anhydride and 1 ml concentrated sulphuric acid are added quickly, while stirring well, stirring is maintained at room temperature for 2 minutes and the reaction mixture is poured into 1.5 litres water. The mixture is stirred for 2 hours and filtered and the crystals are washed with a large amount of water and dried for 6 hours at 70°C. 8.2 g 17J3-acetoxy-17a-ethinyl-5a-androst-2-ene are obtained. • weight yield • theoretical yield • melting point • TLC • IR spectrum • NMR spectrum • HPLC analysis of A~3 82% 95% 126.4°C single spot conforms to the structure conforms to the structure A-3-isomer not visible 0.3% EXAMPLE 11 17fi-Propanoyloxy-17a-ethinyl-5a-androst-2-ene g impure 17fi-propanoyloxy-17a-ethinyl-5a-androstene containing 83% A-2-isomer and 17% A-3-isomer were dissolved in 10 ml methylene chloride. 1 ml acetic anhydride and 0.8 ml concentrated sulphuric acid are added, while stirring well, and the reaction mixture is stirred for 5 minutes and poured into 1 litre water. The mixture is stirred for 4 hours and filtered and the residue is washed with a large amount of water and dried for 4 hours in vacuo at 70°C. 3.9 g 17fi-propanoyloxy-17a-ethinyl-5a-androst-2-ene are obtained. • weight yield • theoretical yield • melting point • TLC • IR spectrum 10 • NMR spectrum • HPLC analysis of A-3 78% 94% 110°C single spot conforms to the structure conforms to the structure A-3-isomer not detectable 0.1% EXAMPLE 12 17fi-Butanoyloxy-17a-ethinyl-5a-androst-2-ene 5 g impure 17fi-butanoyloxy-17a-ethinyl-5a-androstene containing 83% A-2-isomer and 17% A~3-isomer were dissolved in 10 ml methylene chloride. 1 ml acetic anhydride and 0.8 ml concentrated sulphuric acid are added, while stirring well, and the reaction mixture is stirred at room temperature for 5 minutes and poured into 1 litre water. The mixture is stirred for 4 hours and filtered and the crystals are washed with a large amount of water and dried for 4 hours in vacuo at 60°C. 3.7 g 17J3-butanoyloxy-17a-ethinyl-5cr-androst-2-ene are 25 obtained. • weight yield 74% • theoretical yield 89% • melting point 80°C • TLC single spot • IR spectrum • NMR spectrum • HPLC analysis of A~3 conforms to the structure conforms to the structure A-3-isomer not detectable 0.2% EXAMPLE 13 17fi-Pentanoyloxy-17cr-ethinyl-5a-androst-2-ene g impure 17fi-pentanoyloxy-17a-ethinyl-5a-androstene containing 83% A-2-isomer and 17% A-3-isomer were dissolved in 10 ml methylene chloride. 1 ml acetic anhydride and 0.7 10 ml concentrated sulphuric acid are added, while stirring well, and the reaction mixture is stirred at room temperature for 5 minutes and poured into 1 litre water. The mixture is stirred for 4 hours and filtered and the residue is washed with a large amount of water and dried for 15 16 hours in vacuo at 40°C. 3.7 g 17fl-pentanoyloxy-17a-ethinyl-5a-androst-2-ene are obtained. • weight yield • theoretical yield 20 • melting point • TLC • IR spectrum • NMR spectrum • HPLC analysis of A~3 74% 89% 50°C 1 secondary spot of low intensity conforms to the structure conforms to the structure A-3-isomer not detectable 0.2% EXAMPLE 14 17fi-Heptanoyloxy-17a-ethinyl-5a-androst-2-ene g impure 17fi-heptanoyloxy-17a-ethinyl-5cr-androstene containing 83% A~2-isomer and 17% A-3-isomer were dissolved 5 in 10 ml methylene chloride. 1 ml acetic anhydride and 0.7 ml concentrated sulphuric acid are added, while stirring well, and the reaction mixture is stirred for 5 minutes and poured into 100 ml methanol. After stirring for 2 hours, 15 g DOWEXr AG2 X8 anion exchange resin (in the OH- form) are 10 added, the mixture is stirred for 1 hour and filtered, the resin is washed with 20 ml methanol and the combined filtrate and washings are evaporated to dryness. 3.5 g 17A-heptanoyloxy-17a-ethinyl-5a-androst-2-ene are obtained in the form of a pale yellow oil. • weight yield 72% • theoretical yield 86% • melting point liquid at room • TLC temperature 1 secondary spot of low intensity • IR spectrum • NMR spectrum conforms to the structure conforms to the structure A-3-isomer not detectable HPLC analysis of A~3 0.6% EXAMPLE 15 17fl-Hydroxy-17a-ethinyl-5a-androst-2-ene g impure 17fi-hydroxy-17a-ethinyl-5a-androstene containing 83% A-2-isomer and 17% A-3-isomer were dissolved in 20 ml methylene chloride. 1 ml acetic anhydride and 1 ml concentrated sulphuric acid are added, while stirring well, and the mixture is stirred at room temperature for 15 minutes. The reaction mixture was poured into 2 litres water and, after stirring for 4 hours, is filtered and the crystals are washed with a large amount of water and dried for 2 hours in vacuo at 90°C. 7.65 g 17J3-hydroxy-17a-ethinyl-5a-androst-2-ene are obtained. • weight yield • theoretical yield • melting point • TLC • IR spectrum • NMR spectrum • HPLC analysis of A~3 76.5% 92% 165°C single spot conforms to the structure conforms to the structure A-3-isomer not detectable 0.3% The present invention is not limited to the embodiment examples described above, and is, on the contrary, capable of variants and modifications which will be obvious to those skilled in the art.

As has also been indicated in the literature, and in particular in United States of America Patent 4 278 668 (Gueritee), A-2-androstene derivatives of the general formula IV are medicaments which act as inhibitors or against hypophyseal stimulants, depending on the use conditions.

They find various therapeutic applications, such as endometriosis, sterility, certain forms of osseous repair, such as osteoporosis, and in benign diseases of the breast, and in the veterinary field in pseudogestation of bitches.

Claims (1)

1. A process for obtaining a A-2-androstene compound in the pure state from a mixture of A~2(3) and A-3(4)-androstene, characterized in that a mixture of androstenes corresponding to the general formula fi n- H in which the dotted line symbolizes a double bond in position 2(3) or in position 3(4) R represents a hydroxyl which is free, esterified by an organic acid having 1 to 10 carbon atoms or etherified by an alkyl or tetrahydropyranyl radical, R' represents hydrogen, a lower alkenyl radical, a lower alkynyl radical, a lower alkyl radical, a phenyl radical or a cycloalkyl radical, or R and R' together form the oxygen of a ketone function, and the wavy line indicates an a or fi orientation, is subjected to the action of a sulphonating agent in the pure form or in an inert solvent, if appropriate in the presence of a dehydrating agent, to give a A-3-androstenyl-2-sulphonic acid of the general formula II - 19 - in which R and R' have the meanings given above and the non-transformed, pure A~2(3)-androstene derivative of the general formula IV in which the substituents R and R' are defined as above, is obtained. A preparation process according to claim 1, in which the sulphonating agent is sulphuric acid. A preparation process according to claim 2, in which the inert solvent in the sulphonation reaction is chosen from an aliphatic acid, a halogenohydrocarbon, a cyclic ether and a linear ether. A preparation process according to claim 2, in which the sulphonation is carried out in the presence of a dehydrating agent. - 20 - A preparation process according to claim 1, in which the separation of the A~3-androstenyl-2-sulphonic acid is carried out by addition of an aqueous medium which dissolves it. A preparation process according to claim 1, in which the A-3-androstenyl-2-sulphonic acid is isolated by passage over an anion exchange resin. A preparation process according to claim 2, in which the dehydrating agent is an anhydride of an alkylcarboxylic acid, such as acetic anhydride or propionic anhydride. The A-3-androstenyl-2-sulphonic acids of the general formula II in which the substituents R and R' have the meanings given above and the wavy line indicates an a or fi configuration. A process substantially as hereinbefore described with reference to the Examples. An A-2-androstene compound whenever prepared by a process as claimed in any of claims 1 to 7 or 9. - 21 - Dated this 5th day of November, 1986 CRUICKSHANK & CO. Agents for the Applicants 1, Holies Street, Dublin 2. \941S . SPE