A one-pot three-component Biginelli-like reaction of enaminones, aldehydes with urea/thiourea in
the presence of 2-pyrrolidonium bisulphate as an acidic ionic liquid catalyst for the preparation of
6-unsubstituted dihydropyrimidinones is described. The excellent yield, short reaction time, simple
procedure and avoidance of the use of organic solvents are some advantages of this method