Al₂O₃/MeSO₃H: A Novel and Recyclable Catalyst for One-Pot Synthesis of 3,4-Dihydropyrimidinones or Their Sulfur Derivatives in Biginelli Condensation

Abstract

Al₂O₃/CH₃SO₃H (AMA) is an efficient catalyst for the three-component condensation reaction of aldehyde, 1,3-dicarbonyl compound, and urea or thiourea to afford the corresponding 3,4-dihydropyrimidin-2-(1H)-ones in high isolated yield via this procedure, which works very effectively regardless of the electronic nature of the substituent on the ring, although electron-donating groups precipitate the rate of reaction. The catalyst is recyclable and stable at room temperature, and the reaction protocol is simple, is cost-effective, and gives good isolated yield with high purity.

Keywords:

• AMA
• Biginelli
• dihydropyrimidinones
• methansulfonic acid
• recyclable catalysis

ACKNOWLEDGMENT

We gratefully acknowledge the support of this work by the Shiraz University Research Council and Shiraz Faculty of Pharmacy. We are also grateful to Mr. H. Sajedian Fard for helpful cooperation.

Notes

^a 0.1 g, equal to 0.5 mmol H⁺.

^b Isolated yield.

^c The same catalyst was used for each of five runs.

^a Products were characterized by comparison of their spectroscopic data (¹H NMR, ¹³C NMR, and IR) and melting points with those reported in the literature.

^b Isolated yield.

^c The reaction was carried out on a 100-mmol scale.