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

Abstract 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.