One-Pot Synthesis of Hantzsch Dihydropyridine Catalyzed by Ionic Liquid (BmimOAc) and the Oxidative Aromatization of Dihydropyridine Using FeCl3·6H2O

Abstract

A series of 1,4-dihydropyridines were synthesized in one pot synthesis with the yield of 80- 93 % using ionic liquid [b_mim]OAc as catalyst and DMF as solvent. The ionic liquid could be repeatedly utilized 5 times with no decrease of the yield. The aromatization of these dihydropyridines (4a, 4b, 4d, 4f, 4h and 4i) were executed by the action of iron chloride and the post-processing was simplified using ethanol instead of water in dissolving dihydropyridines.