Design,Synthesis And Acaricidal (Insecticidal) Activity Of Diazide Derivatives Containing Thiazoline

Plant diseases and pests are one of the direct factors leading to crop yield reduction and significant economic losses,and how to solve this problem remains a challenging task.With the widespread and long-term use of traditional pesticides,the resistance of field pests to existing insecticides is increasing,and research on the creation of new insecticides is in the ascendant.Green,efficient,and non-target biosafety new insecticides are the mainstream direction in pesticide development today,with natural products as the lead in discovering new insecticides as an important way.Diazide structures have a significant inhibitory effect on the growth of pests,and these compounds are safe for both mammals and non-target organisms.Therefore,taking natural products as the lead and using the principle of sub active molecule splicing,a new class of bishydrazide derivatives is designed,which has important research significance for the creation of new insecticides.The main research content of the thesis is as follows:1、In this thesis,the natural product Desferrithiocin containing thiazoline structure is taken as the lead structure,and according to the bioelectronic isosteric theory and the principle of active substructure splicing,the two active units of diacylhydrazide and thiazoline are spliced,and 28 new diacylhydrazide derivatives are designed and synthesized.The synthesized compounds were characterized by ¹H NMR,¹³C NMR,¹⁹F NMR,and high-resolution mass spectrometry（HR-MS）.2、Plutella xylostella and Tetranychus cinnabarinus were used as test subjects.The biological activity of diamondback moth was tested using the leaf soaking method,and the biological activity of Tetranychus cinnabarinus was tested using the slide immersion method.The preliminary biological activity showed that at a concentration of 500 mg/L at48 hours,most of the compounds showed good inhibitory effects on diamondback moth and Tetranychus cinnabarinus.The lethal rates of compounds A₁,A₅,and A₁₃ on diamondback moth were 100%,97.78%,and 93.33%,respectively.The lethal rates of compounds A₅ and A₁₃ against Tetranychus cinnabarinus were 81.71%and 100%,respectively.When the concentration is 100 mg/L,the insecticidal activity against the diamondback moth is relatively low,and it is good against the spider mite.The insecticidal activities of A₁₉ and A₂₁ are 63.53%and 76.84%,respectively.Conduct insecticidal activity tests on the spider mite cinnabar at 500 mg/L and 100 mg/L for 72 hours.The biological activity test showed that when the concentration of the test drug was 500 mg/L,compounds A₁₃ and A₁₉ had 100%acaricidal activity.At a concentration of 100 mg/L,compounds A₅ and A₁₉ had 91.67%and 96.47%acaricidal activity,respectively;At a concentration of 25 mg/L,the lethal rates of compounds A₅ and A₁₉ against Tetranychus cinnabarinus were 65.75%and 63.95%,respectively.3、On the basis of preliminary screening experiments,we determined the LC₅₀ values of some compounds:A₂,A₅,A₈,A₁₂,A₁₃,A₁₉,A₂₀ and A₂₈ against Tetranychus cinnabarinus,with LC₅₀ values of 51.03,6.52,158.43,88.62,42.49,13.24,45.68,and 116.17 mg/L,respectively.Some of the compounds were superior to the commercial drug spiramycin（107.94 mg/L）.Based on the results of biological activity testing,a preliminary analysis was conducted on the relationship between structure and activity.In summary,in this thesis,we conducted a series of studies on novel diacylhydrazide derivatives con,taining thiazoline structures,and synthesized a series of diacylhydrazide compounds.We found two better acaricidal compounds,A₅ and A₁₉,which provide some reference for future research.