In this work, a facile, metal-free and efficient protocol for the synthesis of thiazolo- and benzothiazolo[3,2- a]pyrimidine-6-carboxylate derivatives using onion peel as catalyst is described. For the first time, the onion peels are used for the synthesis of thiazolo- and benzothiazolo[3,2-a]pyrimidine-6-carboxylate derivatives. The current protocol has numerous advantages, including cost-effectiveness, avoiding the use of external acids and bases, and the high porosity of the natural catalyst has led to the desired products in good to excellent yields. We anticipate that this environmental friendly catalyst presented here will be of great utility in both research institution and industry.
