Direct Nucleophilic Attack/Addition Cyclization and C-H Bond Activation Reactions to Synthesize 3-Benzyl-/3-Benzyl-2-phenyl-benzo[4,5]imidazo[2,1-b]thiazoles

The economic and practical strategies of direct nucleophilic attack/addition cyclization and C-H bond activation reactions to synthesize 3-benzyl-/3-benzyl-2-phenyl-benzo[4,5]imidazo[2,1-b]thiazoles via (Z)-(2,3-dibromoprop-1-en-1-yl)benzene/(3-bromoprop-1-yn-1-yl)benzene, 1H-benzo[d]imidazole-2-thiols and halobenzenes have been developed. With the optimized reaction conditions, the nucleophilic attack/addition cyclization reaction (Cs2CO3, MeCN, 90 degrees C, 24 h) and C-H bond activation reaction [Pd(OAc)(2)/PPh3, p-xylene, 135 degrees C, 24 h] could tolerate various electron-donating and electron-withdrawing groups and afford new benzo[4,5]imidazo[2,1-b]thiazoles in good to excellent yields (up to 93% yield).