Silica immobilized nickel complex: An efficient and reusable catalyst for microwave-assisted one-pot synthesis of dihydropyrimidinones

Dihydropyrimidinones (DHPMʹs) have been prepared by one-pot condensation of aldehydes, urea and 1,3-dicarbonyl compounds in presence of covalently anchored nickel complex on silica as catalyst in microwave under solvent-free conditions. The prepared catalyst was characterized by elemental analysis, BET surface area, atomic absorption spectroscopy (AAS), FT-IR spectroscopy and 13C CPMAS spectral studies. This method in comparison to previously reported methods offers high yields, eliminates the use of organic solvents, reduces reaction time from several hours to few minutes and also the catalyst can be reused without appreciable loss in catalytic activity.