Manganese oxide catalyzed synthesis of anti-HIV N-substituted benzimidazoles via a one-pot multistep process

1, 2-Disubstituted benzimidazoles are drug discovery targets and play an important role in many areas. Herein, non-noble-metal alpha-MnO2 prepared using urea as the additive was found to be an efficient catalyst for the synthesis of antiviral 1,2-disubstituted benzimidazoles via one-pot multistep reactions using dimethyl carbonate and air as green solvent and oxidant, respectively. The catalytic system could tolerate 1, 2-diol or alcohols as raw via cascade oxidation/cyclization/alkylation to realize the desired products in moderate to good yields. The catalyst was characterized by ICP-AES, XRD, BET, SEM, TEM and XPS, which indicates that the surface oxygen species seriously affected the catalytic performance. And the leaching of Na/K ions in tunnels of the catalyst caused loss of catalytic activity of retrieved alpha-MnO2.