K2S2O8-Mediated halogenation of 2-arylimidazo[1,2-α]pyridines using sodium halides as the halogen sources

A convenient halogenation of 2-arylimidazo[1,2-alpha]pyridines using sodium chloride/bromide/iodide as the halogen sources in the presence of K2S2O8 as an easy-to-handle oxidizing agent was developed. The present work offers an efficient and rapid access to 3-chloro-, 3-bromo- and 3-iodo-2-arylimidazo [1,2-alpha]pyridines which can be readily converted to C3-substituted imidazo[1,2-alpha]pyridines by cross-coupling reactions. (C) 2019 Elsevier Ltd. All rights reserved.