Synthesis, Reaction And Bioactivity Of Benzimidazole Derivatives

Benzimidazoles and their derivatives have wide applications in medicine, fungicide, textiles and many other fileds. Recent observations suggest that the substituted benzimidazoles and their derivatives possess potential activity with lower toxicities in the chemotherapeutic approach in man. Moreover, benzimidazoles and their derivatives were distinctively studied for their reaction activities and roles as important intermediate in the organic synthesis.Microwave-assisted organic synthesis is a new and quickly growing area in synthetic organic reactions. Many organic reactions proceed much faster with higher yields under microwave irradiation compared to conventional heating. Microwave--assisted organic reactions allow rapid product generation in high yield under uniform conditions. Therefore, they are ideally suited for combinatorial chemistry.Our work was carried out as followed:1. A series of 2-substituted benzimidazoles were synthesized by the reaction of o-phenylenediamine with corresponding acid in polyphosphoric acid under microwave. 11 Compounds were synthesized in this way first time. They were in good yields and the reaction time was shortened. The effects of irradiation power, irradiation time and the catalysts on the yield were discussed.2. 32 Ferrocenesulfonyl benzimidazole derivatives were synthesized under microwave. They include 13 novel l-ferrocenesulfonyl-2-substituted benzimidazole derivatives, 14 novel 5-nitro ferrocenesulfonylbenzimidazole derivatives and 6-nitro ferrocenesulfonylbenzimidazole derivatives. The reaction time was reduced from 24h to 10-16 min with higher yield. The effects of irradiation power, irradiation time andthe catalysts on the yield were discussed. The crystal structures of 5 ferrocenesulfonyl benzimidazole derivatives were determined by X-ray diffraction.3. 32 Compounds synthesized were tested in vitro against five fungicides: Pythium solani, alternaria lycopersici, gibberella nicotiancola, Gibberella saubinetii, Fusarium oxysporiun f.sp.niveum in comparison with 50% carbendazim wet powder. All compounds showed their fungicidal activities, some showed better activities than the contrast. The relationship between the structures and the fungicidal activities of the compounds was discussed.4. The addition-hydrolysis reactions of benzimidazolium salt with Grignard reagent were reported by our research team. In this paper, the addition-hydrolysis reactions of benzimidazolium salt with Grignard reagent were studied further, the new synthetic methods for phenylacetaldehyde, t-butylmethanal, cyclopentylmethylketone and cyclohexylmethylketone were developed, and the mechanism of the reaction was discussed also.