1,4-Dihydropyridine; Hantzsch synthesis; [Hmim]Tfa; homogeneous catalyst; microwave; multicomponent reaction.
One pot synthesis of 1,4-dihydropyridine derivatives was achieved via condensation of various 𝛽-ketoesters with aromatic/aliphatic aldehydes and ammonium acetate. The reaction was catalysed by a stable and reusable Brønsted acidic ionic liquid (IL), 1-methyl-imidazolium trifluoroacetate ([Hmim]Tfa), under microwave (MW) irradiation. The synergistic combination ofMWwith IL can potentially go a long way tomeet the increasing demand for chemical processes. This homogeneous catalytic procedure is simple and efficient. The catalyst can be reused at least four times with almost complete retention in its activity.