Synthesis And Antifungal Activities Of 7-(1,2,3/1,2,4-1H-Triazol)yl Methylcoumarins

Diseases of crops are different from pests or weeds.Because they are not easy to detect in time,they often cause neglect and difficulty in control,and their harm is even more serious.According to reports,there are as many as 10,000 kinds of plant diseases caused by pathogenic fungi all over the world,and the losses caused by these diseases account for 10%to 30%of the total annual crop losses.At present,bactericides are still composed of chemical pesticides mainly composed of organic compounds.These organic compounds will more or less produce some toxic substances during the degradation process,thereby polluting the environment.At the same time,due to the abuse of fungicides,the resistance of pathogenic bacteria has become increasingly serious,so it is urgent to develop more efficient,low toxicity and low residue pesticide varieties.There are many types of natural products,diverse biological and environmentally friendly.These advantages have led many scholars and researchers to focus on natural products as the leading structure and obtain new types of pesticides through modification,which occupies an important position in pesticide research and development.As an important natural product,coumarin was first obtained from Voling Coumarin in Guyana by Vogel in 1820,200 years ago.Later studies have found that coumarin is widely present in secondary metabolites of higher plants.Coumarin has a variety of biological activities such as antibacterial,antiviral,antitumor,anti-oxidation,anti-HIV,anti-coagulation,etc.,and has a good application prospect.Many kinds of coumarins,such as osthole,neobyakangelicol,pre-caprolactone and sulphate,have been used to inhibit plant pathogens significantly.Azole compounds have attracted high attention in the field of international pesticide research as early as the 1970s because of its high-efficiency and broad-spectrum bactericidal activity,.As early as 1970,the German company Horst developed the first 1,2,4-triazole pesticide-triazophos.Subsequently,the German company Bayer developed a broad-spectrum high-fungi fungicide clotrimazole.Other high-efficiency systemic fungicides such as triazolone and triazole alcohols have also been developed.In this thesis,7-methylcoumarin is used as the lead compound for structural modification and transformation.The active group splicing method is used to introduce 1,2,3-triazole and 1,2,4-triazole to the 7-position methyl group.A total of 307-(1,2,3-1H-triazol)yl methylcoumarins and 25 7-(1,2,4-1H-triazol)yl methylcoumarins synthesized in this paper.None of the compounds have been reported in the literature.All target compounds subjected to nuclear magnetic resonance spectroscopy(1H NMR),carbon spectroscopy(13C NMR)and mass spectrometry(MS)used for structural characterization.In this paper,the growth rate method was used to test the antibacterial activity of the target compounds against six common crop pathogens such as Botrytis cinerea,Alternaria Leaf Spot,Cucumber anthracis,Alternaria solani,Rhizoctonia solani,and Gibberella zeae.The test results show that compounds containing 1,2,3-triazole have a good inhibitory effect on both Botrytis cinerea and Cucumber anthrax,that compounds containing 1,2,4-triazole have a good inhibitory effect on Rhizoctoriza solani at a concentration of 50μg·mL-1,.Among them,the inhibition rate of compound 4c against the Botrytis cinerea was 52.6%,the inhibition rate of compound 1b against Cucumber anthrax was 61.6%,and the inhibition rate of compound 1j against the Rhizoctoriza solani was 59.3%.