Iminophosphorane-mediated annelation of a pyridine ring into a preformed pyridine one: synthesis of naphthyridine, pyrido[1,2-c]pyrimidine and pyrido[1,2-c]quinazoline derivatives
作者:Pedro Molina、Angeles Lorenzo、Enrique Aller
DOI:10.1016/s0040-4020(01)81234-5
日期:1992.1
from 4- and 3-formylpyridines by sequential treatment with ethyl azido acetate and triphenylphosphine, with isocyanides leads to 2,7-naphthyridine, 4, 1,7-naphthyridine 7 and 2,6-naphthyridine 8 respectively. Iminophosphoranes 10 and 22 undergo pyrido annelation by reaction with isocyanates, carbon dioxide, carbon disulfide and acyl chlorides to give pyrido[1,2-c]pyrimidine 11–14 and pyrido[1,2-c]quinazoline