Multicomponent synthesis of novel penta-heterocyclic ring systems incorporating a benzopyranopyridine scaffold

Abstract

A simple one-pot method is reported for the synthesis of several novel series of chromeno[4′,3′:4,5]pyrido[2,3-d][1,2,4]triazolo[4,3-a] pyrimidine-6,14-diones, chromeno[4′,3′:4,5]pyr ido[2,3-d]thiazolo[3, 2-a]pyrimidine-6,14-diones, and chrom- eno[4′′,3′′: 4′,5′]pyrido[2′,3′:4,5]pyrimido[2,1-b][1,3]thiazine-6, 15-dione by a multicomponent reaction of salicylaldehyde, ethyl acetoacetate, and the appropriate fused heterocyclic amines in refluxing glacial acetic acid. The structures of the newly synthesized compounds were established by spectroscopy and elemental analyses. The mechanism of the single-step reaction was elucidated. © 2014 Georg Thieme Verlag Stuttgart New York.