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

Graphical abstract Highlights • A simple and convenient procedure for halogenation of 2-arylimidazo[1,2- a ]pyridines. • A method allows rapid preparation of 3-halo-2-arylimidazo[1,2- a ]pyridines in a short reaction time. • A procedure employ K 2 S 2 O 8 as an easy-to-handle oxidizing agent under convenient reaction conditions. Abstract A convenient halogenation of 2-arylimidazo[1,2- a ]pyridines using sodium chloride/bromide/iodide as the halogen sources in the presence of K 2 S 2 O 8 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- a ]pyridines which can be readily converted to C 3-substituted imidazo[1,2- a ]pyridines by cross-coupling reactions. [ABSTRACT FROM AUTHOR]