Stereoselective synthesis of steroidal (3/R)-spiro-DELTA~2-1',3',4'-oxadiazoline

摘要

Heterocyclic system namely cholest-5-en-(3r)-spiro-DELTA~2 -1',3',4'-oxadiazoline 3 has been synthesized via the reaction of cholest-5-en-3-one semicarbazone 2 with acetic anhydride and pyridine at 80(deg C),in high yield. Cholest-5-en-3-one semicarbazone 2 is obtained by the condensation of cholest-5-en-3-one 1 with semicar-bazide hydrochloride. The products 2 and 3 are characterized by their physical,analytical and spectral(IR,~1H NMR)data.