SYNTHESIS OF THE ANTI-ESTROGEN, △⁴-10β-ACETOXY-17β-HYDROXY-17α-ETHYNYLESTREN-3-ONE

△⁴-10β-acetoxy-17β-hydroxy-17α-ethynyl-estren-3-one (1a, R=Ac, R'=H) and its diacetate (R=R'=Ac) were prepared fom compounds (2) or (5) by the reaction sequence shown in scheme 1. In experimental animals 1 a (R=Ac, R'=H) is nearly 100% effective in preventing pregnancy. Compound 1 a (R=Ac, R'=H) has been examined in the clinic. Urfortunately, preliminary results do not confirm the contraceptive potential suggested by the animalstudies.