Synthesis And Antifungal Activities Of Some Benzimidaszole Derivatives Bearing Isoxazole And Schiff Base Moieties

Study on the synthesis and biological activity of heterocyclic compounds is one of the most focus research topics in pesticide chemistry. The class of compounds has stimulated a great deal of interest due to their structural diversity, high activity, high selectivity, low toxicity and low residue. Heterocyclic compounds have a broad application value in medicine,pesticide, materials, dyes and other fields. Benzimidazole and its derivatives are a class of heterocyclic, with a variety of biological physiological activity and have very important medicinal value in anti-cancer, sterilization, antivirus, insecticidal. On the other side, Schiff bases have broad activity and have a broad range of applications in the fields of biology,medicine and pesticide due to their physiological activity and reactivity characteristics.In order to find highly active pesticide isoxazole was introduced into benzimidazole matrix structure according to the active sub-structure connection in this paper. One series benzimidazole derivatives were synthesized. The main work was summarized as follows:1. A series of 4-(2-benzimidazolyl)-5-substitutedphenyl ideneamino-3-substitutedphenyl isoxazoles(4a~4i) were synthesized from substituted benzaldehyde,hydroxylamine hydrochloride, NCS and 2-benzimidazolyl acetonitrile as starting materials by multi-step reactions. All the target compounds were confirmed by IR,1H NMR, and HRMS. Some experimental processes were improved. The synthetic condition characteristic absorption peaks of the target compounds were analyzed and discussed in details.2. In this paper, the antifungal activity of the target compounds against Botrytis cinerea and Sclerotinia sclerotiorum were tested by the mycelium growth rate method. The results show that, the series compounds have certain inhibition against Botrytis cinerea and Sclerotinia sclerotiorum. Compounds 4c and 4d exhibit good antifungal activity against Botrytis cinerea at a concentration of 100 ?g/m L, with inhibition rate of 54.0% and 50.3%respectively, and their activities are near to the control(chlorothalonil, inhibition rate 55.3%).On the other hand, compounds 4c,4d and 4f display high antifungal activity against Sclerotinia sclerotiorum at 100 ?g/m L, which inhibition rate are 75.1%, 76.1%, and 71.3%.