Design, synthesis of bisbenzimidazole dithiol derivatives and analogs

The benzimidazole scaffold is an important pharmacophore and one of the preferred structures in medicinal chemistry due to the wide range of biological activities of its derivatives. Here in this article, the synthesis of two series of compounds, namely bis(thiobenzimidazol-2-yl)methane derivatives and analogs (4a-e) and bis(benzimidazol-2-yl)dithiol derivatives and analogs (5a-e) are described. These compounds were synthesized by first designing 2-mercaptobenzimidazole derivatives and analogs (2a-e) by action of orthophenylenediamine and analogs (1a-e) with carbon disulfide. Reaction of thiols (2a-e) with diiodomethane leads to bis(thiobenzimidazol-2-yl)methane derivatives and analogs (4a-e). Their treatment in glacial acetic acid led to their oxidation to bis(benzimidazol-2-yl)dithiol derivatives and analogs (5a-e). The structures of the synthesized compounds were characterized by 1H, 13C Nuclear Magnetic Resonance (NMR), and High-Resolution Mass Spectrometry (HRMS) analyses.