A new and efficient synthesis of imidazo[1,5-a] pyridine derivatives by a tandem aza-Wittig / electrocyclic ring closure of N-vinylic phosphazenes
作者:Francisco Palacios、Concepción Alonso、Gloria Rubiales
DOI:10.1016/0040-4020(95)00083-k
日期:1995.3
prepared by reaction of N-vinylic phosphazene 3, obtained from phosphorus ylide 5 and 2-cyanopyridine 4, with aldehydes. Formation of fused heterocycles 1 can be explained through aza-Wittig reaction of phosphazene 3, followed by 1,5-electrocyclic ring closure of the resulting aldimines 2. Phosphazene 3 undergoes pyrido annelation by reaction with Diethyl Ketomalonate to give isoquinoline derivative
咪唑并[1,5-a]吡啶1是通过使由叶立德磷5和2-氰基吡啶4获得的N-乙烯基磷腈3与醛反应制得的。稠合杂环1的形成可以通过磷腈3的aza-Wittig反应来解释,然后通过1,5-电动环闭合所得醛亚胺2来解释。磷腈3通过与酮戊二酸二乙酯反应而进行吡啶酮成环,得到异喹啉衍生物9。