A facile pseudo three component reaction for the synthesis of benzo [4,5]imidazo[1,2-a]pyridine derivatives

The benzimidazole moiety is amongst the diversely active scaffolds as antifungal, antibacterial, antiviral, anticancer and antimalarial agents.1‒4 Therefore, developing new approaches towards the synthesis of benzimdazole fused heterocycles have always been on need.5 Also, indeno and isoquinolino fused heterocycles have gained greater attention because of their medicinal and synthetic importance over years and the broad range of biological activity.6‒8 Therefore, benzimidazole fused indene, pyridine or isoquinoline are of great interest in general and many synthetic procedures are available till date.1 Moved by these results we desired to achieve a facile general synthetic protocol to obtain these diverse molecules. Multicomponent reaction has always proved to be a versatile tool towards the synthesis of structurally diverse and complex heterocycles in simple one pot manner.9 Our research group is actively engaged in developing multi-component reaction protocols for the synthesis of skeletally diverse, functionalized and biologically relevant small heterocyclic hybrids.10‒12 We report a simple and rapid procedure for the preparation of benzo[4,5]imidazo[1,2a]pyridines (Figure 2) with 2-(1H-benzo[d]imidazol-2-yl)acetonitrile.