Studies on the Constituents of the Aerial Parts of Dioscorea tenuipes FRANCH. et SAVAT. II. Diotigenin 4-Acetate and the Corresponding Furostanol Glycoside

Abstract

The structures of two steroidal substances, G₁ and S_E1, isolated from the fresh aerial parts of Dioscorea tenuipes FRANCH. et SAVAT. (Dioscoreaceae), were investigated. G₁ (mp 221-222°, [α]_D -10.0°, C₂₉H₄₆O₆) and S_E1 (mp 172-174°(decomp.), [α]_D +134.4°, C₃₆H₆₀O₁₂·2H₂O, Ehrlich reaction +) were characterized as diotigenin 4-acetate (I) and the corresponding furostanol 26-O-glucoside, 4β-acetoxy-22-methoxy-5β-furostane-2β, 3α, 26-triol 26-O-β-D-glucopyranoside (VIII), respectively. VIII is the first reported furostanol glucoside corresponding to spirostanol acetate and is most likely to have been formed secondarily from the 22-hydroxy analog (IX), mp 165-166°(decomp.). IX is regarded as the prototype compound of I. The mass spectrum of VIII and compositions of the major fragment ions are presented.