A rapid access to novel and diverse 3-oxothiazolo[3,2-c]pyrimidine-8-carboxylates using multicomponent Mannich cyclisation reactions.

An efficient synthesis of novel 3-oxotetrahyrothiazolo[3,2-c]pyrimidine-8-carboxylate derivatives was developed by reacting 4-oxothiazolidines with formaldehyde and amines under very mild conditions. A variety of novel thiazolopyrimidine carboxylates were attained rapidly by double Mannich/intramolecular cyclisation reactions in very good yields.