Magnetic nanoparticles supported imidazolium-based ionic liquids as nanocatalyst in microwave-mediated solvent-free Biginelli reaction

Abstract

The magnetic Fe3O4 nanoparticles supported imidazolium-based ionic liquids (MNPs–IILs), namely 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium hydrogen sulfate (MNPs–IIL–HSO4), 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium acetate (MNPs–IIL–OAc) and 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium chloride (MNPs–IIL–Cl) were used as efficient new catalysts for the one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones under microwave irradiation and solvent-free conditions in excellent yields. Utilization of easy reaction conditions, catalyst with high catalytic activity and good reusability, and simple magnetically work-up, makes this green protocol as an interesting option for the economic synthesis of Biginelli compounds. Microwave technology as an eco-friendly green synthetic approach has gradually been used in this organic procedure. Combining the advantages of microwave irradiation and magnetically nanocatalyst, this method provides an efficient and much improved modification of the original Biginelli reaction. We believe that this procedure appears to have a broad scope with respect to variation in the 3,4-dihydropyrimidin-2(1H)-ones (thiones). we have developed a rapid, effective, validated and environmental-friendly method for the synthesis of dihydropyrimidinones (thiones) using Fe3O4 nanoparticles immobilized imidazolium salt catalyst in microwave irradiation and solvent-free conditions. Reduced reaction times, high turnover frequency, high yields of products, absence of solvent and recyclability of catalyst make our catalyst a valuable system addition to previously reported methods. This green methodology should be amenable to construct new substituted dihydropyrimidinones scaffolds with potential biological applications.