RESOLUTION OF AN INTERMEDIATE OF RACEMIC NORGESTREL

Optically active D-and L-norgestrel were obtained by resolution of recemic intermediate, 19-nor-13β-ethyl-3β, 17β-dihydroxy-17α-ethynyl-4-androsten(Ⅲ) prior to oxidation with MnO₂. Compound Ⅲ was first changed to its hemisuccinic ester which was then treated with (+)-α-methyl ethyl phenylamine. The enantiomer salts (Va,Vb) were easily separated by fractional recrystallization with methanol. Subsequent hydrolysis of the optically active Va and Vb in alcoholic sodium hydroxide, followed by neutratization with 36% acetic acid, gave the corresponding optically active Ⅵa and Ⅵb which on oxidation with MnO₂ afforded the desired D-α_D²²-41,2°(c 0.076, CHCl₃) and L-Norgestrel α_D²²+39.5°(0.081, CHCl₃) respectively.