Synthesis of N-Acetylbenzimidazole Derivatives

抄録

For the structure determination of thiazolo [3, 2-a] benzimidazol-3 (2H)-one derivatives (2 or 3) they were converted to the corresponding 1-acetylbenzimidazoles (4) by desulfurization. The latter compounds (4) were alternatively prepared by the cyclization of 2-aminoacetanilide derivatives (5) with CS₂ in dimethylformamide (DMF), followed by desulfurization with Raney Ni. However, the reactions of 5 with ethyl orthoformate/H₂SO₄ in DMF gave a mixture of 4 and its acetyl-rearranged product (7).