Demissidine is an indolizidine alkaloid isolated from several potato species. A simple synthesis of demissidine stereoisomers and analogues from a common steroidal sapogenin tigogenin is presented in the paper. The key intermediate in the synthesis of these compounds is readily available tigogenoic acid. Its step-by-step transformation to indolizidine yielded 20R,25R or 20R,25S products while the direct reductive amination produced the 20S,25R compound (25-epi-demissidine).

中文翻译：

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茄碱生物碱脱甲啶立体异构体的合成及类似物

Demissidine是从几种马铃薯中分离得到的吲哚并立生物碱。本文介绍了从常见的甾体类皂素原tigogenin合成简单的demissidine立体异构体和类似物的方法。这些化合物合成中的关键中间体是容易获得的tigogenoic酸。其逐步转化为吲哚并咪唑产生20 R，25 R或20 R，25 S产物，而直接还原胺化产生20 S，25 R化合物（25-表位-去甲替丁）。