I2 and the Deep Eutectic Solvent ChCl–Tartaric Acid Promote the Addition–Oxidative Cyclization of 2-Aminopyridines and Chalcones to Obtain Imidazo[1,2-a]pyridines

The synthesis of nitrogen-containing heterocycles remains a subject of significant interest due to their applications in medicinal chemistry and materials science. This paper describes the preparation of imidazo[1,2-a]pyridine using a catalytic system consisting of the deep eutectic solvent (DES) choline chloride (ChCl)–tartaric acid (1:2) and I2 by reaction between 2-aminopyridines and chalcones (1,3-diphenylprop-2-en-1-ones). The proposed mechanism suggests the activation of the chalcone carbo