Synthesis And Fungicidal Activity Of1-Substituted-2-benzoimidazolyl-2-acetonitriIe Oxime Ether

Pesticides are making progress in the direction of high efficiency, low toxicity,green and pollution-free. Benzimidazole derivatives have been the focus in the field ofpesticide research at home and abroad due to the advantage of high systemic,selectivity, low toxicity, etc. In addition, because of their special structure,physiological activity and reactivity characteristics, this kind of compounds arepresent in a variety of drugs as an important structural unit. They have a broadspectrum of biological activity and a wide range of applications, such as anticancer,sterilization, antivirus, anti-HIV, insecticide and so on. In numerous developedheterocyclic compounds, morpholine and piperazine derivatives have receivedincreasing interests in diverse potential biological activities such as inseticidal,anticancer, antifungal and antiinflammatory activities. As well, oxime-ethercompounds are important bioactive substances, and they are widely used in pesticidesand pharmaceuticals because of the vital role in biological fields such as anticancer,antimicrobial, and antiviral activities, so the research for the synthesis andapplications of benzimidazole derivatives have always drawn much attention.In order to find highly active pesticide varieties, oxime ether was introduced intobenzimidazole matrix structure according to the law of biological electron rowprinciple and active sub-structure connection in this paper. Two series of fifteencompounds containing benzimidazole were synthesized. The main work wassummarized as follows:(1) The Target compounds2-(1H-1-(4-morpholinacylethyl/4-methylpiperazineacylethyl)-benzoimidazol-2-yl) acetonitrile oxime ether Ia-jand IIa-jwere synthesizedstarting from o-phenylenediamine and chloroacetic acid via the reaction of cyclization,nuclephilic substitution reaction of alkylation, N-alkylation, oximation andetherification with a series of aryl halides and alkyl halides. The structures of targetcompounds are shown as follows: (2) All the target compounds were confirmed by1H NMR, IR and MS. Someexperimental processes were improved. The post-processing operation was simplifiedand the yield of target compounds was improved. The synthetic conditioncharacteristic absorption peaks of the target compounds were analyzed and discussedin details.(3) In this paper, the antifungal activities of the series compounds against Botrytiscinerea and Sclerotia sclerotium were tested by the mycelium growth rate method.Results showed that most of the compounds has some antibacterial activity to the twofungi, all of those EC50values are less than100μg/mL. Compared with the control(carbendazim), target compounds If, Ig, IIf, IIgpossess high antifungal activity, withEC50values of10.82,10.46,14.74,29.02μg/mL against Sclerotia sclerotium,respectively, all less than that of carbendazim (41.02μg/mL). And the EC50of If, Ig,IIf, IIgrespectively were10.78,11.14,7.14,13.99μg/mL, which were less than thatof carbendazim (18.71μg/mL). So we can know that the activities are increased whenwe introduced several different groups into the target compound. On the other hand,the activity of compounds I was higher than that of compounds II in against Sclerotiasclerotium, but the two series of compounds had same effect in against Botrytiscinerea.