Synthesis of naphtho[1',2'4,5 ]imidazo[2,1‐b]thiazoles via CuCl‐catalyzed cross‐coupling of ethynylimidazothiazoles with N‐tosyl hydrazones and their antitubercular activity.

Described herein is a tandem reaction involving a copper chloride‐catalyzed cross‐coupling and an allene‐mediated cyclization of substituted ethynylimidazo[2,1‐b]thiazoles with aromatic N‐tosylhydrazones, producing naphtho[1',2'4,5]imidazo [2,1‐b]thiazoles in very good yields. This protocol offers the advantages of one‐pot conversion from stable and readily available substrates as well as good functional group compatibility to prepare polycyclic N‐fused heteroaromatic systems. Moreover, the new compounds exhibited promising antitubercular activity.