into a mixture of dienes which react with maleic anhydride to give two crystalline adducts (X and XI). Adduct XI was shown to possess the same carbon skeleton as atisine (I), a diterpenoid alkaloid, by its conversion to the hydrocarbon (XXI). Hydrocarbon XXI has recently been synthesizesd from maleopimaric acid, the Diels-Alder adduct of the diterpene levopimaric acid and maleic anhydride, and has been
十二烷酸(IV),一种先前合成的二萜,已被转化为二烯的混合物,该二烯与
马来酸酐反应,得到两种结晶加合物(X和XI)。通过将加合物XI转化为碳氢化合物(XXI),其具有与阿替辛(I)(一种二
萜类生物碱)相同的碳骨架。烃XXI是最近由马来海马酸,二萜左旋海马酸和
马来酸酐的Diels-Alder加合物合成的,并且与阿西斯丁直接相关。根据其反应并根据其各种转化产物的NMR光谱研究,初步建议将结构X用于第二个加合物。XI的合成提供了正确的立体
化学分子,其中包含犬
嘧啶的双环(2.2.2)-
辛烷C,D环系统,此外,