Hydroxy-γ-sanshool was prepared with 19.5% overall yield through eight steps. Wittig reactions of ylides with ethyl 4-oxobut-2-enoate as well as (2E,4E)-hex-2,4-dienal were key steps to construct a carbon skeleton. The 2E,4Z-isomer in ethyl 8-hydroxyocta-2,4-dienoate can be isomerized to the desired 2E,4E-isomer with iodine as a catalyst, and free tetradeca-2,4,8,10,12-pentaenoic acid can be purified
通过八步制备羟基-γ-
山梨醇,总产率为19.5%。烷基化物与4-氧代丁-2-烯酸
乙酯以及(2 E,4 E)-hex-2,4-二烯基的Wittig反应是构建碳骨架的关键步骤。可以使用
碘作为催化剂将8-羟基辛基-2,4-二烯酸
乙酯中的2 E,4 Z-异构体异构化为所需的2 E,4 E-异构体, 12五烯酸可通过结晶在1%
乙酸乙酯的
乙酸纯化ñ
正己烷。其他中间体中的杂质可以很容易地除去,合成过程可以避免由于不稳定的4-
溴丁烷-1-醇的氧化而合成或使用
4-溴丁醛,而且后处理很简单。 图形摘要