Abstract
A simple and efficient synthesis of 3,4-dihydropyrimidinones or thiones is described, using silica-supported ceric sulfate [Ce(SO4)2-SiO2] as a heterogeneous catalyst from an aldehyde, 1,3-dicarbonyl compound, and urea or thiourea at 110 °C under solvent-free conditions. Compared with the classical Biginelli reaction, this new method consistently has better yields, short reaction time, easy separation, and tolerance toward various functional groups.
ACKNOWLEDGMENT
We gratefully acknowledge the financial support from the Key Discipline of Industrial Catalysis.
Notes
a Isolated yield (%) of product.
b Isolated yield (%) of the catalyst recycling reactions.
c Reaction conditons: aldehyde (50 mmol), 1,3-dicarbonyl compound (50 mmol), urea (75 mmol), and Ce(SO4)2 (0.3 g), 110 °C, 40 min.