Design,Synthesis And Insecticidal Activity Of Pyridalyl Analogues

Pyridalyl is an insecticide mainly for controlling lepidopteran pests.Comparing to the existing insecticides,its structure and mechanism are completely different.Besides,This insecticide has the characteristics of high efficiency and low toxicity,and no cross-resistance with existing insecticides.Aiming at all kinds of the lepidopteran pests on vegetables and cotton,it shows excellent insecticidal activity.However,it has little effect on various arthropods.Therefore,in the process of integrated pest control,pyridalyl has a good control effect.In this paper,pyridalyl is structurally modified and modified according to the skeleton structure of pyridalyl and the previous work of the research group,and it is expected that compounds capable of controlling pests efficiently can be obtained.By analyzing the structure of pyridalyl and combining with the previous work basis of the research group,we designed a series of pyridalyl analogs.Firstly,an azide group was introduced on its pyridine ring,and a series of analogs of pyridalyl were designed and synthesized by modification of different functional groups.Then,studying the structure-activity relationship and insecticidal activity,we retained the azide group on the pyridine ring,modified its intermediate chain portion,and changed its chain moiety getting a ring.Finally,considering the structural properties of azido-functional groups and structure-activity relationships,the azide group was replaced by similar cyano groups and a series of compounds were synthesized later.This paper systematically summarized the structure and properties of pyridalyl while conducting in-depth research on its synthesis method and structure optimization.Furthermore,54 target compounds were synthesized with the unique structure of pyridalyl.All target compounds were characterized by 1H NMR,13C NMR and HRMS.The synthesized compounds were also tested for insecticidal activity,some compounds show superior insecticidal activity.Combing with the bioassay data,it was found most of the target compounds containing azide-based fragments and maintaining a chain alkyl group in the middle showed good insecticidal activity.According to the analysis of the structure,the compounds with strong electron-withdrawing groups had higher activity.When with a larger functional group,the activity of the compound was substantially lost;when substituting the intermediate chain portion to a ring such as a five-membered ring or a six-membered ring,the activity of the compound was substantially zero.When the three-membered ring was introduced at the one and two position,the activity was better.The reason might be that the introduction of the ring in the middle of the compound influenced the flexibility of the structure of the whole compound,and the other part may be that the solubility of the compound was poor,resulting in poor biological activity;When the azido-functional group was replaced by a strong electron-withdrawing group cyano group,most of the chain compounds maintained good activity,while the intermediate chain was six-membered ring,compounds had less activity.The result further proved the influence of the flexibility and solubility of the target molecule on the activity,and also laid a solid foundation for the further development of the pyridyl analog.