abstract |
Δ 15 -Steroids of the formula ##STR1## wherein R 1 is a hydrogen atom, trialkylsilyl or acyl; R 2 is ethynyl, chloroethynyl or propinyl; and X is an oxygen atom, ##STR2## or NOR 4 wherein R 3 is a hydrogen atom or acyl and R 4 is a hydrogen atom, acyl, alkyl or tetrahydropyranyl, possess progestational and ovulation and nidation inhibiting activities. |