Synthesis Of Novel Pesticidal Heterocyclic Sulfuric Diamide Derivatives Using SuFEx Click Reaction

Click Chemistry is a new method for synthesizing a large number of compounds in a short time,which is of great significance for organic synthesis.With the development of the synthesis of new pesticide compounds,click chemistry is gradually applied to the synthesis of new agricultural compounds,and is more and more widely used in people’s life.In recent years,Sharpless group in launch with copper ions（Ⅰ）for the catalyst after the first click on the chemical reaction,and then developed based on sulfur（Ⅵ）-fluorine exchange（SuFEx）click reaction.SuFEx reaction raw materials are economical to obtain,easy to operate,high yield and no by-products,which can effectively solve the shortcomings of high cost and high time consumption in the synthesis of chemical pesticides.In order to more effectively develop high pesticide reactive molecules,this research will be based on sulfur（Ⅵ）-for the first time of fluorine exchange（SuFEx）click reaction applied to new pesticide synthesis and screening of candidate compounds.In this study,a series of novel heterocyclic sulfonamide derivatives were designed and synthesized by using SuFEx reaction as the technical method for the synthesis of new compounds and 2-chloro-5-aminomethylthiazole as the raw material.All the derivatives were confirmed by ¹H NMR and ¹³C NMR analysis.The crystal structure of compound 6j was also obtained by X-ray single crystal diffraction and its symmetrical structure was further explained.The economic and feasibility of the synthesis of active molecules by SuFEx reaction was proved by the screening of insecticidal and bactericidal biological activities.The common pests Plutella xylostella（P.xylostella）and Lipaphis erysimi（L.erysimi）on crops,Pyricularia grisea（P.grisea）and Thanatephorus cucumeris（T.cucumeris）common pathogenic fungi on rice,and Botrytis cinerea（B.cinerea）common on vegetables such as cucumber were selected as test object to test the biological activity of the synthesized compounds.Preliminary results showed that most of the target molecules exhibited good bioactivities against P.xylostella.There are 10 compounds with a mortality rate of more than50%against P.xylostella at a concentration of 100μg·mL^-1.Among them,compounds 5j,6e,6f,and 6j have prominent insecticidal effects,and their LC₅₀ are 39.07μg·mL^-1,20.43μg·mL^-1,3.87μg·mL^-1,and 2.42μg·mL^-1 can be used as lead compounds for further research.Most of the synthetic compounds are not very effective against L.erysimi.When the mycelial growth rate method was used to test the bacteriostatic effect of the compounds,it was found that some compounds could also exhibit satisfactory fungicidal activity towards plant pathogens P.grisea.Nine compounds have a 50%or more inhibitory rate against P.grisea at a concentration of 50μg·mL^-1,among which compounds 4r and 6c have outstanding antibacterial effects,and their EC₅₀ are 4.93μg·mL^-1 and 3.43μg·mL^-1,respectively.Most of the synthesized compounds have modest inhibitory effects on T.cucumeris and B.cinerea.In this paper,the structure-activity relationship of the compound to insecticidal activities against insect pests such as P.xylostella and the antibacterial effect of the compound on pathogenic fungi such as P.grisea was analyzed.In the synthesized novel pesticidal heterocyclic sulfuric diamide derivatives,when the substituted group R is a heterocyclic group,the compound’s insecticidal activity against P.xylostella will increase.The compound6j having a symmetrical structure showed the most excellent activity.In the determination of the fungicidal activity of compounds,the presence of electron-withdrawing groups such as F and OCF3 on the R group has an important effect on the activity,which can obviously improve the fungicidal activity of the compound.These results provide new ideas for the development of highly effective guided pesticide candidate compounds.