Copper-doped mesoporous silica supported dual acidic ionic liquid as an efficient and cooperative reusability catalyst for Biginelli reaction

Abstract

A series of MCM-41 supported functionalized ionic liquids doped with copper species were prepared, characterized and evaluated as catalysts in the Biginelli reaction. Most of these supported ionic liquids perform well in the reaction, especially the multifunctional copper coordinated MCM-41 supported heterogeneous catalysts (0.5)IL-TiCl5@MCM-41@Cu(15) and (0.5)IL-HSO4@MCM-41@Cu(15). The catalytic tests revealed that (0.5)IL-HSO4@MCM-41@Cu(15) was the best and powerful catalyst in the Biginelli reaction for the preparation of 3,4-dihydropyrimidinones with high to excellent yields. The catalyst can be easily separated from the reaction mixture by filtration and reused in six consecutive cycles without significant loss in catalytic activity.