Facile Synthesis of Benzimidazoles via N‑Arylamidoxime Cyclization

A facile synthesis of benzimidazoles was described by a one-pot process containing acylation–cyclization of N-arylamidoxime. This method provided an alternative synthesis of benzimidazoles with a certain diversity of substituted groups in acceptable yields (up to 96%). More importantly, the construction of bis-benzimidazole (8), the key intermediate for making telmisartan, was achieved by adopting this method that enabled avoiding the undesired nitration with nitric/sulfuric acid and the cyclization in polyphosphoric acid in the existing operations.