GREEN AND EFFICIENT SYNTHESIS OF DIHYDROPYRIMIDINONE ANALOGUES VIA HPA-CLAY CATALYZED BIGINELLI REACTION

This study introduces an environmentally sustainable approach for the synthesis of 3,4-dihydropyrimidin-2(1 H )-ones (DHPMs), via the Biginelli reaction. A heterogeneous catalyst, Heteropolyacid-Clay (HPA-Clay), is developed by immobilizing H 5 PV 2 W 10 O 40 on Montmorillonite KSF clay. The catalyst exhibits enhanced stability and catalytic efficiency, confirmed through X-ray powder diffraction and scanning electron microscopy. Utilizing a one-pot multi-component strategy under solvent-free conditions, various aldehydes, urea or thiourea, and ethylacetoacetate generate DHPMs with excellent yields and reduced reaction times. Catalysed by 2 mol% HPA-Clay, the process aligns with green chemistry principles, emphasizing cost-efficiency, environmental sustainability, and recyclability. The catalyst demonstrates consistent activity over multiple cycles, highlighting its potential for advancing Biginelli reactions.