Comparison of Catalytic Effect of Alkali and Alkaline Earth Metals Hydrogen Sulfate: As the Promoter for an Efficient Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones under Solvent-Free Conditions

Abstract

Alkali and alkaline earth metals hydrogen sulfate catalyzed the one-pot three component condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1H)-ones in high yields at 80 °C. Our results showed that Biginelli reaction not only is pH dependent, but the cation of catalyst plays an important role.

Keywords

• biginelli reaction
• dihydropyrimidinones
• catalytic effect
• lithium hydrogen sulfate
• sodium hydrogen sulfate
• potassium hydrogen sulfate
• magnesium hydrogen sulfate