chemical considerations. Compounds 6a and 6b were synthesized by alkylation of compound 5 with beta-(N,N-diethylamino)ethylchloride hydrochloride and 1-(2-chloroethyl)pyrrolidine hydrochloride, respectively. Compound 3g (isomeric mixture) prevented pregnancy in 60% of rats at 10 mg/kg daily dose administered orally on days 1 to 7 of pregnancy; however, its only isolable 7 beta-hydroxy isomer, 3h,