One-pot, Green and Efficient Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones or Thiones Catalyzed by Citric Acid

One-pot three-component condensation of ethyl acetoacetate, aldehyde and urea or thiourea in refluxing ethanol in the presence of catalytic amounts of citric acid afforded the corresponding 3,4-dihydropyrimidin- 2(1H)-ones/thiones in high yields. The catalyst is reusable and can be applied several times without any decrease in product yield.

Biginelli reaction; One-pot synthesis; 3,4-Dihydropyrimidin-2(1H)-ones; Citric acid.