Novel Synthesis of 3,5-Disubstituted-5H-Thiazolo[3,2-α]Pyrimidine

Structural similarity between thioamides and 3,4-dihydropyrimidin-2(1H)-thiones made us to explore the reaction of 3,4-dihydropyrimidin-2(1H)-thiones with doubly electrophilic alkynyl(aryl)iodonium tosylates for synthesis of C2-N3 linked thiazolo[3,2-a]pyrimidine derivatives. In the reported research, we have employed alkynyl(aryl)iodonium salts for the ring annulation of 3,4-dihydropyrimidin-2(1H)-thiones to give thiazolo[3,2-a]pyrimidine derivatives using Triton-B as phase transfer catalyst instead of other bases like K2CO3 or Et3N used earlier.