An efficient green protocol for the synthesis of coumarin fused highly decorated indenodihydropyridyl and dihydropyridyl derivatives

A simple, convenient, environmentally benign, and mild synthetic method has been established to afford highly decorated indenodihydropyridine and dihydropyridine derivatives employing a green solvent ethyl-L-lactate and an organo-catalyst (+/-)lactic acid. A wide range of functional groups were tolerated in the developed protocol. The target molecules were obtained in moderate to good yields applying the current method. (c) 2012 Elsevier Ltd. All rights reserved.