The Biginelli condensation:: A novel and efficient regioselective synthesis of dihydropyrimidin-2(1H)-ones using lithium bromide

Various substituted 3,4-dihydropyrimidin-2(1H)-ones were synthesised in one-pot reaction of aldehydes, beta-ketoesters and urea using LiBr in tetrahydrofuran in excellent yields without any side reactions as observed by Biginelli and others.