Abstract
In order to obtain progestational hormone with durable potency, progesterone 3-monopropylene ketal (I) and 17α-hydroxy-1-dehydroprogesterone (II) were prepared. (II) was prepared first by acetylation of pregnenolone to form 5, 17 (20)-pregnadiene-3β, 20-diol diacetate, double bond at 17 (20)-position selectively epoxidized with perbenzoic acid, and hydrolyzed to 17α-hydroxypregnenolone. Oppenauer oxidation of this latter substance to 17α-hydroxyprogesterone (III) and subsequent oxidation with selenium dioxide afforded (II). Esterification of (II) is difficult that the ester of (III) was oxidized with selenium dioxide to obtain the ester of (II). Examinations of progestational activity of (I), (II)-acetate, (II)-caproate, (III)-acetate, and (III)-caproate by the modified Clauberg method showed that they had potency weaker than progesterone but examination by the modified Allen-Corner method indicated that the ester of (II) seemed to have a slightly longer duration of potency than the ester of (III).
