Recent updates on the synthesis of thiazolopyrimidines derivatives

Fused heterocyclic ring structures play an important role in the enhancement of pharmaceutical actions of the molecules and have been reported to have efficient medicinal applications in recent decades. Thiazolopyrimidines are fused heterocyclic molecules consisting of thiazole and pyrimidine ring systems that have significant importance in medicinal chemistry. Thiazolopyrimidines have been prepared by the reaction of 4,5-dihydrothiazol-2-amine with diketones, ethoxymethylene malonic esters, acetylene dicarboxylic esters and ethyl(chloroformyl)acetate. Herein, we have discussed a variety of synthetic approaches, e.g., condensation reaction, Biginelli condensation reaction, Knovenagel condensation reaction, ultrasonic assisted synthesis, multistep reaction, single step reaction, from chalcones, microwave-mediated synthesis, Pd-catalyzed coupling reaction, U-SH technique, and green synthesis, for the formation of isomeric forms of thiazolopyrimidines, including thiazolo[3,2-a]pyrimidine, thiazolo[5,4-d]pyrimidine, and thiazolo[4,5-d]pyrimidine and their derivatives.