Design And Synthesis Of New Schiff Base Compounds, Research On Biological Activity And Preliminary Exploration Of The Mechanism Of Action

Based on the structure of Schiff base,two series of sixty-two Schiff bases were designed and synthesized.The compound was characterized by ¹H NMR,¹³C NMR,¹⁹F NMR,HRMS and many more.In addition,tobacco mosaic virus?TMV?was used as the research object,the target compound was tested for antiviral activity,and the interaction between the compound with excellent passivation activity and the tobacco mosaic virus coat protein?TMV-CP?was studied by microscale thermophoresis?MST?and molecular docking.At the same time,some compounds with strong binding ability to cucumber mosaic virus coat protein?CMV-CP?were screened by MST,and verified by the anti-cucumber mosaic virus in vivo experiment.The work of this paper is summarized as follows:1.Thirty-four Schiff base compounds of pyrazolo[3,4-d]pyrimidine were designed and synthesized.The target compound was studied for anti-TMV biological activity.The results showed that some compounds had excellent anti-tobacco mosaic virus activity.In particular,the compounds 5y and 5aa showed the best therapeutic activity,theirs EC₅₀0 values are 272.8?g/mL and 283.5?g/mL,respectively,were significantly better than the commercial drug Ningnanmycin(EC₅₀=324.5?g/mL),And theirs EC₅₀0 values of the passivation activity were 70.3?g/mL and 53.8?g/mL respectively.Among them,compound 5aa was better than Ningnanmycin(EC₅₀=55.35?g/mL).In addition,MST assay showed that compound 5aa had strong binding ability to TMV-CP?Kd=9.8±2.6?M?,which was much larger than ribavirin?Kd=64.7±2.12?M?,similar to Ningnanmycin?Kd=9.75±0.55?M?.And the results of the molecular docking study are consistent with the results of the passivation activity.2.Designing and synthesizing twenty eight o-carboxamide benzamide Schiff base compounds,and the activity of the target compound against TMV was studied.The results showed that the target compound had excellent antiviral activity.In particular,the therapeutic activity of the compound 10i(EC₅₀=75.86?g/mL)was significantly better than that of the commercial drug Ningnanmycin(EC₅₀=362.4?g/mL),and the compounds 10p showed superior protective activity compared to Ningnanmycin(EC₅₀=265.9?g/mL),its EC₅₀0 value is 124.5?g/mL.Moreover,10e and 10f exhibited slightly higher passivation activity than the commercial drug Ningnanmycin(EC₅₀=50.02?g/mL),theirs values are 41.5?g/mL and 49.0?g/mL.The interactions between the compounds and TMV-CP or CMV-CP proteins were studied by MST,MST assay showed that compound 10e had strong binding ability to TMV-CP?Kd=10.4±2.8?M?little more than Ningnanmycin?Kd=11.9±1.7?M?.Which indicated that the MST assay results were consistent with the activity test results,and the compounds 10k?Kd=10.6±2.9?M?with strong binding ability to CMV-CP protein were screened,similar to Ningnanmycin?Kd=10.4±2.1?M?.And verified by corresponding in vivo experiments.