The ketalization of 11alpha-hydroxy-18-methyl-DELTA4-estrene-3,17-dione (I) with ethylene glycol (A) by means of ethyl orthoformate and p-toluene sulfonic acid gives the diketal (II), which is oxidized with CrO3 in acetone yielding the ketone (III). The Wittig reaction of (III) with triphenylmethyl-phosphonium bromide (B) by means of NaH in benzene-DMSO affords 11-methylene-18-methyl-DELTA4-estren-3,17-dione diethyleneketal (IV), which is hydrolyzed with HCl in acetone to the diketone (V). The reaction of (V) with pyrrolidine (C) in methanol gives the N-pyrrolidinyl derivative (VI), which is condensed with potassium acetylide (D) in THF yielding 17alpha-ethynyl derivative (VII). Finally, this compound is hydrolyzed with acetic acid in methanol - water.

The ketalization of 11alpha-hydroxy-18-methyl-DELTA4-estrene-3,17-dione (I) with ethylene glycol (A) by means of ethyl orthoformate and p-toluene sulfonic acid gives the diketal (II), which is oxidized with CrO3 in acetone yielding the ketone (III). The Wittig reaction of (III) with triphenylmethyl-phosphonium bromide (B) by means of NaH in benzene-DMSO affords 11-methylene-18-methyl-DELTA4-estren-3,17-dione diethyleneketal (IV), which is hydrolyzed with HCl in acetone to the diketone (V). The reaction of (V) with pyrrolidine (C) in methanol gives the N-pyrrolidinyl derivative (VI), which is condensed with potassium acetylide (D) in THF yielding 17alpha-ethynyl derivative (VII). Finally, this compound is hydrolyzed with acetic acid in methanol - water.