Synthesis And Fungicidal Activities Of Substituted Benzimidazole Ethyl Ketone Oxime-ether

Nowadays, pesticides are developing towards high efficiency, low toxicity, and environmental friendly. Since the 70s of the 20th century, DuPont company of the United States and BASF of Germany developed the first oxime ether fungicides (Cymoxanil and herbicides Alloxydim), Oxime ether compounds have attracted more and more attention in pesticide due to its advantages of good anti-bacterial activity, herbicidal activity, anti-plant-viral activity, high efficiency, low toxicity and low residue. In the 1990s, oxime ether developed rapidly, a large number of fungicides and herbicides have been developed. At present, the molecular design,synthesis and biological activity of oxime ether compounds remains one of the focus in new pesticide creation.Because of the heterocylcle of pesticide have various structures, all kinds of substitutes, better bioactivities, better safety, being suit for future demand ,it gradually becomes the main trend of the future pesticide . Since 1960, it is reported that all kinds of 2-aminobenzimidazole is a wide strong systemic fungicide by Krapping. The development of the benzimidazole and its derivatives, especially two replacements of benzimidazole, is regarded as a category with a variety bioactivities of heterocyclic. Since the emergence of these fungicides, bactericides developed to a new stage, and there is a new systemic fungicide, and fungicides in the history of this epoch-making significance.The action mechanism, structure-activity relationships, biological activity, synthetic methods, and research progress of benzimidazole oxime ether compounds were comprehensively discussed.In order to find highly active pesticide varieties, we put oxime ether moiety into benzimidazole matrix structure according to the law of biolog ical electron row principle and active sub-structure connection. Two series eight kinds of O-substituted benzyl-1-substituted benzyl benzimidazole oxime ether (Ⅰ,Ⅱ) were synthesized with o-phenyl enediamine, lactic acid, chromium trioxide, hydroxylamine hydrochloride, and alkyl halides as the starting materials; Another two series (Ⅲ,Ⅳ) 14 kinds of O-substituted be nzyl (alkyl) benzimidazole oxime ether were synthesized with acetyl benzimidazole and benzyl (alkyl) oxy hydrochloride as starting material . The structu re of 22 new compounds were confirmed by 1H NMR, IR and elemental analysis.The experimental methods were discussed in detail, parts of the experiment were improved, post-processing operations were simplified, the yield of the target compounds was improved, synthetic conditions,spectral properties of the target compounds were analyzed and discussed systemly , the 1H NMR and IR spectroscopy of target compounds were determined. The synthetic compounds were listed as follows:ⅠO-substituted benzyl-N-substituted benzyl -2 - (1H-benzimidazole) ethyl ketone oxime etherⅡO-substituted benzyl-N-substituted benzyl -2 -(1H-6-chloro-imidazole) ethyl ketone oxime etherⅢO-substituted benzyl(alkyl) -2 - (1H-benzimidazole) ethyl ketone oxime etherⅣO-substituted benzyl(alkyl) -2 - (1H-6-chloro-imidazole) ethyl ketone oxime etherIn the article, the antifungal activities of the series compounds against Alternaria alternata Botrytis cinereapers and Sclerotinia sclerotiorum were respectively tested by the mycelium growth rate method, and the results indicated that they had good antifungal activity against Alternaria alternata Botrytis cinereapers and Sclerotinia sclerotiorum.Ⅲ_g,Ⅳ_g compounds which the EC50 value of Alternaria alternata Botrytis cinerea were about 15μg/mL,are better than carbendazim.Ⅰ_b,Ⅰ_d,Ⅲ_c compounds had better activity against Sclerotinia sclerotiorum , EC50 value of Sclerotinia sclerotiorum were about 20μg / mL, lower than carbendazim.