【摘要】 通光藤[Marsdenia tenacissima（Roxb.）Wight et Arn.]为云南民间抗癌药用植物。从其藤茎提取的粗甙经水解、皂化后得到一个新的主要甙元,称通光藤甙元甲（tenacigenin A）。通光藤甙元甲分子式 C₂₁H₃₂O₅,熔点255—260℃,属 C₂₁-甾体化合物,能用常法制得二乙酰化合物（Ⅲ）,三乙酰化物（Ⅳ）需在剧烈条件下才能得到。三个羟基中有两个可被氧化成六元环酮（Ⅵ）。另两个氧原子则以环氧的形式存在。通光藤甙元甲用醋酐和对甲苯磺酸于100℃加热30小时后得到3β、12β、14β-三乙酰-5α-甾烷-7（8）、9（11）-二烯-20-酮（Ⅸ）,后者用铂黑在醋酸中氢化得（Ⅹ）。据上述化学反应和红外光谱、紫外光谱、核磁共振谱及质谱数据,作者提出通光藤甙元甲的结构为（Ⅰ）。更多还原

【Abstract】 Tenacigenin A was obtained from crude glucoside of Marsdenia tenacissima （Roxb.）Wight et Arn., a folk antitumor drug in Yunnan, by treatment with acid and base. This compound C₂₁H₃₂O₅, mp.255—260℃, belonging to C₂₁-steroidal type, readily yielded a diacetate（Ⅲ）and under forcing condition a triacetate（Ⅳ）.Two of the three hydroxyl groups were able to be oxidized to diketone（Ⅵ）, which were atta- ched to the six-membered rings.The other two oxygen—atoms existed as in the form of epoxy.Tenacigenin A afforded 3β, 12β, 14β-triacetoxy-5α-pregn-7（8）, 9（11）-diene- 20-one（Ⅸ）, which was hydrogenized with Pt in AcOH to（Ⅹ）, by successive treatment with Ac₂O and PTS at 100℃ for 30 hr. Accoring to the above chemical reactions（Fig.3）and data of IR, UV, NMR （Fig.1）and MS（Fig.2）, the structure of tenacigenin A has been suggested as（Ⅰ）.更多还原