Studies on the Constituents of Asclepiadaceae Plants. XLIV. Components of Cynanchum caudatum MAX. Structure of 20-O-Cinnamoylsarcostin, 12-O-Cinnamoylikemagenol and 20-O-Cinnamoylikemagenol

Abstract

Three new polyoxypregnane derivatives were isolated from the rhizomes of Cynanchum caudatum, and their structures were established as 20-O-cinnamoylsarcostin (VI), 12-O-cinnamoylikemagenol (X) and 20-O-cinnamoylikemagenol (XI) on the basis of chemical and spectral evidences. In the elucidation of their structures, an acyl migration of C-12β ester group to C-20α was found and used for structural studies.