Synthesis And Biological Activity Of Myricetin Derivatives Containing Quinazoline And Sulfonamide

Myricetin is a kind of polyhydroxy flavonoids,which has broad biological activities such as antibacterial,anti-cancer and anti-virus.Quinazoline is a kind of heterocyclic compounds with antibacterial,anti-virus,anti-tumor and other biological activities.Sulfonamide is a kind of broad-spectrum biologically active active group,which has a variety of biological activities such as antibacterial,weeding,anti-cancer and anti-virus.In this thesis,with myricetin as the lead compound,introducing active groups containing quinazoline and sulfonamide,Designed and synthesized myricetin derivatives containing quinazoline(A₁-A₂₂)and myricetin containing sulfonamide were designed and synthesized Derivative B series(B₁-B₂₄).All the target compounds were characterized by ¹H NMR,¹³C NMR and HRMS,and the fluorine-containing compounds were characterized by ¹⁹F NMR.And the biological activity of all target compounds against plant pathogens and TMV were tested.The results of antibacterial activity showed the compounds A₁₅,B₁,B₃and B₄had good inhibitory activity against Xanthomonas oryzae pv.oryzae,and their EC₅₀values were 13.9,36.0,38.3 and 40.1?g/m L,which were better than the control drugs bismerthiazol and thiediazole-copper(88.9 and 68.4?g/m L).Compound B₁₆has a good inhibitory activity against Xanthomonas axonopodis pv.Citri,and its EC₅₀value is 41.4?g/m L,which is better than The control drugs bismerthiazol and thiediazole-copper(92.9 and 69.7?g/m L).Compounds A₃,A₁₆,B₁₁,B₁₃,B₁₅,B₁₆,B₂₀and B₂₄have good inhibitory activity against Ralstonia solanacearum.The EC₅₀values were 1.1,7.5,6.0,4.0,10.0,4.0,5.1 and 4.5?g/m L,respectively,which were better than the control drugs bismerthiazol and thiediazole-copper(38.5 and 184.8?g/m L).The in vivo experiment of resistance to Xanthomonas oryzae pv.oryzae was tested,and the results showed that the compound A₁₅had better curative and protective activity against Xanthomonas oryzae pv.oryzae in vivo.Scanning electron microscopy(SEM)imaging results showed that the antibacterial mechanism of compound A₁₅against Xanthomonas oryzae pv.oryzae was that the bacterial body was dried up and curled by acting on the cell surface,resulting in the incomplete bacterial structure and thus achieving the antibacterial effect.The antibacterial mechanism of compound B₁₆on Ralstonia solanacearum was that it acted on the bacterial surface membrane,resulting in wrinkles on the surface of bacteria,and some ruptured,so as to achieve the antibacterial effect.The semi-leaf spot method was used to test the anti-TMV activity of the synthesized compounds.The results showed that at the test concentration of 500?g/m L,the target compound A showed certain inhibitory activity against TMV.Among them,the therapeutic activities of compounds A₃and A₁₉against TMV were52.8%and 49.2%,which were better than the control drug Ningnanmycin by 41.7%.