Synthesis of Erythrina and Related Alkaloids. Part XXXII. Studies toward Total Synthesis of Non-aromatic Erythrina Alkaloids. (2). A General Method for Synthesis of Perhydro-6H-pyrido (2,1-i) indole Derivatives: Synthesis of Isoerythroidine Skeleton. .
作者:Yoshisuke TSUDA、Akiko ISHIURA、Shinzo HOSOI、Kimiaki ISOBE
DOI:10.1248/cpb.40.1697
日期:——
A general method for synthesis of a physiologically important skeleton, perhydro-6H-pyrido[2, 1-i]indole, through cyclization of an active methylene group to an N-acyliminium, was developed. Treatment of the ketoester 5 with BF3·Et2O in methylene chloride resulted in deacetalization of the ethylene acetal group accomapnied with the expected double cyclization to give the tricyclic product 8 in 83% yield, and 8 was smoothly decarbomethoxylated to give decahydro-6H-pyrido[2, 1-i]indole-2, 6-dione (9). The former compound 8 was converted into derivatives of the isoerythroidine skeleton, 14 and 16.
本研究开发了一种通过将活性亚甲基环化为 N-酰亚胺来合成具有重要生理意义的骨架--全氢-6H-吡啶并[2,1-i]吲哚的一般方法。在二氯甲烷中用 BF3-Et2O 处理酮酯 5,乙炔缩醛基团发生脱乙醛化反应,同时发生预期的双环化反应,得到三环化合物 8,收率为 83%。前一种化合物 8 被转化成异赤藓酮类骨架的衍生物 14 和 16。