CeCl₃-Catalyzed a Highly Efficient and Eco-friendly Synthesis of New and Densely Functionalized Thiazolo[3,2-a]Pyrimidins via Biginelli-type Reaction

5-Carboxanilide-dihydropyrimidinone derivatives were prepared by three-component Biginelli reaction of acetoacetanilide, aromatic aldehydes and thiourea in the presence of CeCl₃ as an expedient catalyst and used as key intermediates for the highly efficient and eco-friendly synthesis of new and densely functionalized thiazolo[3,2-a]pyrimidin derivatives with use of dimethyl and diethyl acetylenedicarboxylate in ethanol at ambient temperature (conventional magnetic stirring).