A facile one pot synthesis of thiazolo[3,2-a]benzimidazole and pyran fused polyheterocyclic scaffolds

An efficient synthesis of dihydro-4H-benzo[4,5] imidazo[2,1-b] pyrano[2,3-d] thiazole by a multicomponent route starting from 2-((1H-benzo[d] imidazol-2-yl) thio)-1-phenylethan-1-one, an aromatic aldehyde and malononitrile is described. This protocol features a metal free approach with good substrate scope and decent yield. The heterocyclic skeleton obtained in this study may have interesting biological properties.