Study On The Synthesis, Biological Activity Test And Preliminary Mechanism Of 5-aminopyrazole-4-(1,3,4-oxadiazole) Sulfide Derivatives

Heterocyclic compounds have been widely used in many fields.Currently,they have been the hot topic because of their broad spectrum of biological activity.Among of the compounds,pyrazole,1,3,4-oxadiazoles,and thioether compounds have broad-spectrum biological activities in agricultural prevention,such as weeding,insecticidal,bactericidal,and anti-plant viruses.In our previous work,pyrazole and 1,3,4-oxadiazole sulfides showed great activity against tobacco mosaic virus?TMV?.The preliminary mechanism of action of these compounds have been studied and a potential target"TMV CP"have been found.In this paper,a series of 5-aminopyrazole-4-?1,3,4-oxadiazole?thioether derivatives have been designed and synthesized by molecular docking and structure optimization,and the target compounds were tested for their anti-plant virus biological activities using the half-leaf method.The interaction between active activity molecule Y31 and target proteins TMV CP have been detected by microscale thermophoresis?MST?.The preliminary mechanism of the compounds was further verified by the method of proteomics analyze.Thirty novel 5-aminopyrazole-4-?1,3,4-oxadiazole?thioether derivatives were synthesized by hydrazinobenzene as starting material.All target compounds were identified by ¹H NMR,¹³C NMR and HRMS.The preliminary bioactivity test showed that the target compounds exhibited good anti TMV activity at 500?g/mL concentration.Among of them,the curative activity of Y-1,Y-5,Y-19,Y-20 and Y-31 were 50.7±2.3%,54.5±9.3%,58.0±9.9%,50.8±6.9%and52.7±3.8%?Ningnanmycin 54.3±2.9%?,respectively.The EC50 values of protection activity were 15.7?g/mL,12.5?g/mL,36.9?g/mL,11.5?g/mL,and 11.9?g/mL,respectively,much better than Ningnanmycin?40.3?g/mL?.Then compound Y-31 was chose for the preliminary mechanism study.Interaction between compound Y-31 and TMV CP was detected by MST.The results showed that compound Y-31 had strong interaction relationship with TMV CP,and the binding constant Kd reached 2.7?M,better than that of Ningnanmycin?Kd=4.5?M?.Molecular docking showed that there were four potential sites between compound Y-31 and TMV CP,such as GLN46,GLU50 and two different chains LYS53.The analysis of proteomics research showed that compound Y-31 can significantly regulate the photosynthetic intensity,reaction rate,and plant energy conversion rate of tobacco leaves,affecting the plant's ability of fixing the carbon source,and the metabolites of the TCA cycle,thus affecting plants metabolic system.