Design,Synthesis And Fungicidal Activity Of Styrene Trifluoromethyl Ketone Derivatives

Styrene trifluoromethyl ketone compound had broad-spectrum in vitro fungicidal activity,but it only had good in vitro fungicidal activity,while in vivo fungicidal activity was poor.Through research,it was found that styrene trifluoromethyl ketone had light instability.In this paper,styrenyl trifluoromethyl ketone was used as the lead compound,and a series of 27 styrene trifluoromethyl ketone derivatives were synthesized by introducing different functional groups to improve the photostability and in vivo antifungal activities.Among them,20 compounds were new,and all compounds were characterized by Nuclear magnetic resonance(¹H NMR and ¹³C NMR),High resolution mass spectrometry（HRMS）to verify the chemical structure.The mycelial rate method was used to determine the in vitro activity of the target compounds against phytopathogenic fungi,and the compound 1 with higher activity was screened,and the cross-resistance between compound 1 and commercial agents was determined;the turbidimetric method was used to determine the pair of compound 1 in vitro and in vivo control effect of plant pathogenic bacteria;spray method was used to determine the in vivo control effect of compound 1 on plant pathogenic fungi,and the distribution and content of compound 1 in wheat was determined by HPLC.The contents of this paper are listed as follows:（1）Photostability:Firstly,the reason for the poor activity of compound 5 in vivo was solved.By using TLC and LC-MS as detection means,it was found that compound 5 begun to decompose at 12 h under sunlight,and compound 5 was completely decomposed at 32 h under high-pressure mercury lamp,however,compound 1 did not start to decompose at 32 h under high-pressure mercury lamp.（2）Antifungal activity:The results showed that most compounds have broad-spectrum in vitro antifungal activity against 8 phytopathogenic fungi at 10μg m L^-1.The EC₅₀values of compound 1 against Botrytis cinerea and Pyricularia oryzae were 3.806 and 7.296μg m L^-1,respectively.At a concentration of 100μg m L^-1,compound 1 showed excellent protective activities against Podosphaera xanthii,Puccinia striiformis West,Puccinia sorghi and Odium heave Steinm,and its inhibition rates were 100,100,98.3 and 100%,respectively.（3）Cross-resistance:The results showed that there was no cross-resistance between compound 1 and the commercial carbendazim,boscalid and azoxystrobin.（4）Antibacterial activity:The results showed that compound 1 had excellent in vitro bactericidal activity against Xanthomonas oryzae pv.oryzae（Xoo）and Xanthomonas oryzae pv.oryzicola（Xoc）,with EC₅₀values of 8.294 and 25.916μg m L^-1.At a concentration of 200μg m L^-1,the protective and curative activities of compound 1 against Xanthomonas oryzae pv.oryzae（Xoo）were 56.1%and 57.4%,which were equivalent to that of zhongshengmycin（66.4%,68.7%）.（5）Uptake and translocation:The content of compound 1 in wheat plants was determined by HPLC,and the distribution and accumulation of compound 1 in wheat roots,stems and leaves were quantitatively analyzed.The results showed that compound 1 had the characteristics of acropetal and basipetal translocation in wheat plants.