Fe2+supported on hydroxyapatite-core-shell-γ-Fe2O3nanoparticles: As a novel, efficient and magnetically-recoverable catalyst for the synthesis of dihydropyrimidinones derivatives

Fe2+supported on hydroxyapatite- core-shell magnetic γ-Fe2O3 nanoparticles (γ-Fe2O3@HAp-Fe2+ NPs) is reported as a novel, efficient, reusable and heterogeneous catalyst. In this protocol, we used this catalyst for the synthesis of 4-dihydropyrimidin-2(1H)-ones/thiones in good to high yields by the reaction of aromatic aldehyde, β-dicarbonyl and urea/thiourea under solvent free condition.The catalyst can be readily isolated by using an external magnet and no obvious loss of activity was observed when the catalyst was reused in seven consecutive runs. The mean size and the surface morphology of the nanoparticles were characterized by TEM, SEM, VSM, XRD and FTIR techniques.