Environment-Friendly Protocol for the Chlorination of Imidazoheterocycles by Chloramine‑T

An environment-friendly method for the chlorination of imidazoheterocycles has been developed using chloramine-T, a novel chlorinating reagent. A bunch of C-3 chloro-substituted imidazo­[1,2-a]­pyridines with variety of functionalities have been synthesized in good yields under neat condition at room temperature within very short time. This chlorination process is also applicable to imidazo­[2,1-b]­thiazole scaffolds. The present methodology is relevant to gram-scale synthesis. The major advantages of this system such as wide applicability, easy availability of reactants, open-air and metal- and solvent-free reaction conditions, no need of work-up, and simple purification technique represent a green synthetic protocol.