Synthesis of angular-substituted tetracyclic azepino-indole derivatives via N-acyliminium ion cyclization
作者:Yong Sup Lee、Byung Joon Min、Yong Kyu Park、Jae Yeol Lee、Sook Ja Lee、Hokoon Park
DOI:10.1016/s0040-4020(99)00808-x
日期:1999.11
A concise and efficientsynthesis of tetracyclic azepino-indole derivatives 2 having a substituent at the angular position has been accomplished through an N-acyliminiumioncyclization. The coupling reaction of indol-3-yl-ethylamine 3 with 4-or 5-keto-acid 4 followed by cyclization reaction of the resulting tautomeric mixtures of keto-amide 5 and hydroxylactam 6 in refluxing formic acid provided 2