Direct Synthesis of Trichloro‐thiazolo[3,2‐a]pyrimidine and Thiazolo[2,3‐b]quinazoline Derivatives

An efficient one‐pot method for synthesis of new biologically active thiazolo3,2‐a ]pyrimidine and thiazolo2,3‐b ]quinazoline derivatives is described via reaction of pentachloropyridine with fused pyrimidine‐2(5H )‐thiones or quinazoline‐2(1H )‐thiones. These reactions were carried out in the presence of potassium carbonate as a base in acetonitrile as a solvent to produce products 3a – n in good‐to‐excellent yield. Pentachloropyridine is doubly electrophilic building blocks for the formation of ring annulated thiazolo3,2‐a ]pyrimidine and thiazolo2,3‐b ]quinazoline products.