A magnetic nanoparticle supported Ni2+-containing ionic liquid as an efficient nanocatalyst for the synthesis of Hantzsch 1,4-dihydropyridines in a solvent-free dry-system

Abstract

The highly efficient synthesis of 1,4-dihydropyridines (1,4-DHPs) is reported via the condensation reaction of aldehydes, ethyl acetoacetate and ammonium acetate, using an environmentally benign Ni2+-containing 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium chloride ionic liquid on magnetic Fe3O4 nanoparticles (IL–Ni(II)–MNPs) as a new catalyst under solvent-free conditions at 70 °C. The method presented here applies the tenets of green chemistry to generate biologically interesting products in solvent-free media. The key features of this protocol from the green chemistry point of view are the use of a heterogeneous and reusable catalyst, high yields of products, and short reaction times. The catalyst can be easily recovered from the reaction mixture using an external magnet, and reused several times without significant loss in performance.