An efficient Pd-catalyzed intramolecular cyclization reaction followed by formation of benzimidazole derivatives: Synthesis of novel quinolin-fused benzo[d] azeto[1,2-a]benzimidazole analogues

Novel quinolin-fused benzo[d]azeto[1,2-a]benzimidazole analogues have been synthesized from o-phenylene diamine and various substituted 2-chloro-5-(2-methylquinoline-4-yl) benzaldehyde through Pd-mediated simultaneous CH–NH and CH–CX bond activation via intramolecular cyclization reaction followed by formation of benzimidazole derivatives. Developed two step, one pot route for quinoline fused four membered azeto[1,2-a] benzimidazole derivatives through Pd-catalyzed cross coupling reaction. The synthesis was carried out by using Pd2(dba)3 as a catalyst, Xphos as a ligand, Cs2CO3 as a base and toluene as a solvent and developed its mechanistic pathway.