A one-pot synthesis of substituted pyrido[2,3-b]indolizines

An efficient and novel approach to the synthesis of substituted pyrido[2,3-b]indolizine-10-carbonitriles was developed. These structures are practically unavailable through previously described methods. The cascade transformation involves the reaction of α,β-unsaturated carbonyl compounds with a stable dimer prepared from 1-(cyanomethyl)pyridinium chloride. The reaction was performed under reflux conditions in ethanol/water and in the presence of sodium acetate. This procedure represents a eco-friendly regioselective approach to the pyrido[2,3-b]indolizine core structure.