Studies On Synthesis And Fungicidal Activity Of Benziminazole Derivatives

Benzimidazoles are important compounds for pharmaceutical and organic synthesis.Their derivatives have various physiological and pharmacological activities, such as anti-virals,anti-cancers,anti-fungals, anti-inflammatodes, treatment of hypoglycemia and physiological disorders, and other pharmacological effects. 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 studied for their reaction activities in the organic synthesis. The study of benzimidazole fungicides following thsoe main directions: 1-substituted benzimidazoles, 2-substituted benzimidazoles, multi-substituted benzimidazoles, other types of benzimidazoles etc.Nine heterocyclic acid intermediates were synthesized from methyl ketone, diethyl oxalate or dimethyl oxalate, hydroxylamine hydrochloride, hydrazine hydrate. And then 23 target compounds were synthesized from heterocyclic acid intermediates and o-phenylenediamine or substituted o-phenylenediamine, of which 19 derivatives were first studied. Their structures were characterized by 1H-NMR, IR. and MS.Twenty-Three Compounds were tested in vitro against 6 fungi: Botrytis cinerea, ternaria solani, Glomerellacingulata, Fusarium oxysporum vasinfectum, Pyricularia grisea, Fusarium graminearum in parison with tiabendazole at concentration of 100mg/L. All compounds showed their fungicidal activities, among which compound e1 showed better activities than other compounds. In comparison with tiabendazole, inhibition rates of e1 closed to that of Azoxystrobin, while against alternaria solani , Glomerella cingulata and Pyricularia grisea, espectively 65.5%,74.8%, 67.7%. And the inhibition rates were equal to tiabendazole, while against Botrytis cirerea, Fusarium vasinfectum, Fusarium graminearum, espectively 100%, 100%, 100%.The relationship between the structures and the fungicidal activities of the compounds was discussed.