3,4-Dihydropyrimidin-2(1H)-ones were synthesised in high yields by one-pot three-component Biginelli condensation in the presence of room temperature ionic liquids such as 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4) or hexafluorophosphorate (BMImPF6) as catalysts under solvent-free and neutral conditions.

★★★★☆ Jiajian Peng and Youquan Deng. Tetrahedron Letters 42 (2001) 5917–5919.