Brønsted Acidic Ionic Liquid–Catalyzed One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones and Thiones Under Solvent-Free Conditions

Abstract

An efficient and convenient procedure for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones by condensation of ethylacetoacetate, aldehydes, and urea or thiourea in the presence of methylimidazolium hydrogensulfate is described. Aromatic and aliphatic aldehydes reacted easily to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones and thiones under solvent-free conditions. The use of nontoxic and inexpensive materials, straightforward and clean workup, short reaction times, and good yields are the advantages of this method.

Keywords:

• Biginelli reaction
• Brønsted acidic ionic liquid
• dihydropyrimidinones
• methylimidazolium hydrogen sulfate

ACKNOWLEDGMENTS

We gratefully acknowledge the funding support received for this project from the Isfahan University of Technology (IUT), Iran (A. R. H.) and Grant GM 33138 (A. E. R.) from the National Institutes of Health, USA. Further financial support from Center of Excellency in Sensor and Green Chemistry Research (IUT) is gratefully acknowledged.

Notes

^a The yields refer to the isolated pure products.

^a The yields refer to the isolated pure products.