Development of synthetic method for C-H functionalization of heterocycle

Abstract

A gentle and eco-friendly method for C-H functionalization, wherein C-3 halogenation of imidazo[1,2-a]pyridines with micellar catalysis, has been developed. This innovative approach combines surfactant with an environmentally friendly and cost-effective oxidant in a waterbased system. Notably, the reaction proceeds under ambient conditions and requires only minimal amounts of potassium halides for functionalization. This method promotes cost-effectiveness, is easy to operate, and improves overall process efficiency, aligning with the principle of green chemistry. Moreover, this protocol has been successfully adapted for the halogenation of other heterocyclic compounds such as pyrazolo[1,5-a]pyrimidine and 4H-pyrido[1,2- a]pyrimidin-4-one, highlighting its versatility. Additionally, this approach is suitable for scale-up synthesis. The surfactant aqueous solution can be reused for up to 5 reaction cycles without compromising yield.