Design, Synthesis And Biological Activities Of Novel Benzimidazole Derivatives

A series of novel benzimidazole derivatives were designed and synthesized, and their biologicalactivities were evaluated in this paper. It mainly contains the following two parts:Part I: Twenty benzimidazole derivatives containing chrysanthemum acid moiety were designedand synthesized according to substurcture combination strategy.A series of novel benzimidazole compounds were designed and synthesized using the method ofsubstructures combination. These compounds combined the benzimidazole scaffold and chrysanthemumacid moiety in a single structure. The structure of title compounds were confirmed by 1HNMR, MS, IRand their preliminary biological activities were tested. Their results showed that: all the compoundsshowed insecticidal activity against both Lipaphis erysimi and Plutella xylostella in vivo at a singleconcentration(400mg/L), the mortality against P. xylostella was 5.26%-33.33% and the mortalityagainst L. erysimi was 32.26%-69.23%; all the compounds have moderate to good fungicidal activity invitro: their inhibitory activity against Pyricularia grisea, Botrytis cinerea, Sclerotinia sclerotiorum,Colletotrichum orbiculare was good, but the inhibitory activity against Phytophthora capsici,Phytophthora infestans, Rhoizoctonia solani was low; the title compounds also showed certaininhibitory activity to Echinochloa crusgalli(L.) and Amaranthus retroflexus(L.). The EC50 values ofcompounds indicate that: the inhibitory activity of B13 against B. cinerea was almost 1.5 times that ofthiabendazole and almost four times of azoxystrobin; compound B9 against S. sclerotiorum was almost2.5 times that of thiabendazole and almost two times that of azoxystrobin; B13 against P. grisea wasalmost 1.4 times that of thiabendazole.Part II: The design and synthesis of benzimidazoles derivatives by modifying substructure andsubstituent groups.A series of novel benzimidazole compounds were designed and synthesized by modifyingsubstructure and substituent group basis on the structure-activity relationship of previous section. Thestructures of compounds were confirmed by 1HNMR, IR, and then their preliminary biological activityagainst fungi and weed were performed. Indoor biological activity tests showed that: all the compoundsshowed good inhibitory activity against Pyricularia grisea, Botrytis cinerea and Sclerotiniasclerotiorum at the concentration of 100 mg/L, but lower inhibitory activity against Watermelonanthracnose.The inhibition rate of compound B29 against both Echinochloa crusgalli(L.) andAmaranthus retroflexus(L.) was above 85% at the concentration of 300 mg/L, whilst compound B53 inhibitory activity against E. crusgalli(L.) is lower, but its inhibitory activity against Amaranthusretroflexus(L.) was as high as 90.84%. The EC50 values of compounds indicate that: the inhibitoryactivity of B56 against B. cinerea was almost twice that of azoxystrobin; compound B65 against S.sclerotiorum was almost twice that of thiabendazole and 1.65 times that of azoxystrobin; B33 against P.grisea was almost 1.25 times that of thiabendazole.In summary, we designed and synthesized some novel and effecient benzimidazole derivatives,experiments demonstrated that these compounds have various biological activities, the study provided agood basis for the further related work and was wroth further studying.