A simple, green and one-pot four-component synthesis of 1,4-dihydropyridines and their aromatization

A simple, green and cost-effective protocol was achieved for the solvent free synthesis of 1,4-dihydropyridines catalyzed by AlCl3 · 6H2O as a mild and effective catalyst at 60 °C in high yields. 1,4-Dihydropyridines thus formed were aromatized to pyridines by in situ generation of HOCl employing AlCl3 · 6H2O/H2O2/H2O/EtOH as an excellent reagent system under domestic microwave irradiation (MWI). Both the synthesis and oxidation steps were efficiently accomplished in one-pot four-component fashion following the same protocol.