Calcium fluoride: an efficient and reusable catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and their corresponding 2(1H)thione: an improved high yielding protocol for the Biginelli reaction

A simple and effective synthesis of 3,4-dihydropyrimidinone derivatives from aldehydes, 1,3-dicarbonyl compounds, and urea/thiourea in ethanol by using calcium fluoride as catalyst has been described. Compared with classical Biginelli reaction conditions, this new method has the advantage of excellent yields and shorter reaction times. Also, the catalyst can be reused without any reduction in efficiency.