Studies on the Steroidal Components of Domestic Plants. XVII. The Structure of Yonogenin, a New Steroidal Sapogenin from Dioscorea Tokoro MAKINO.

Abstract

Two new sapogenins, yonogenin and kogagenin, and tokorogenin were isolated from the epigeous part of Dioscorea Tokoro MAKINO. The structure of yonogenin was established to be 25D, 5β-spirostane-2β, 3α-diol (Va) by its degradation to samogenic acid (IIa) and by its conversion via Δ²-olefin (III) to samogenin (IVa), which was epimerized to original yonogenin (episamogenin). 25D, 5β-Spirostane-2α, 3β-diol (VIIa) was also prepared.