Synthesis And Antifungal Activities Of 6-aminocoumarin And Its Pyrrole Derivatives

According to reports,more than 10,000 plant diseases caused by pathogenic fungi worldwide,and the losses caused by the crops account for 10%to 30%of the total annual loss of crops.Because of China has a vast territory,a wide variety of crops,and a variety of crop diseases.Plant diseases are a serious threat to agricultural production in China.After a series of metabolic changes in a plant,chemical metabolites become non-toxic and harmless substances,some still remain quite toxic,or metabolize new toxic substances,and even become carcinogenic teratogenic substances.Pollution to the environment.Not only that,the long-term use of fungicides,the resistance of bacteria is becoming more and more serious.Therefore,it is of great significance to develop a new high-efficiency green fungicide with a novel mechanism of action.As an important natural product,coumarin has been in the history of more than 200 years since its first separation.Coumarin compounds have a variety of biological activities,such as anti-depression,anti-oxidation,anti-inflammatory,analgesic,antibacterial,anti-tumor,anti-asthmatic,anti-viral and anti-coagulant effects,and are effective ingredients of many traditional Chinese medicines.Many coumarin-like natural products such as osthole,umbelliferone,pre-caprolactone,coralin,alizarin and sulphate have significant inhibitory effects on plant pathogenic fungi.In this thesis,Umbelliferone used as a lead compound to modify its structure.The pyrrolyl group introduced into the 6-position of coumarin by reactive group splicing to study the antibacterial activity of the target molecule.In this thesis,17 kinds of 6-nitrocoumarin,17 kinds of 6-aminocoumarin and 34 kinds of 6-pyrrocoumarin synthesized,57 of not 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 target compounds against six common crop pathogenic fungi,such as Rhizoctonia solani,Botrytis cinerea,Botrytis cinerea,Fusarium graminearum,Cucumber anthracis and Apple spotted fungi.The results showed that most of the compounds inhibited six pathogenic fungi,some 6-nitrocoumarin（1j-lq）and 6-pyrrole coumarin（3a,3m,3j,4b,4c,4e and 4g）It has good antibacterial activity against rice sheath blight pathogen,and the half effective intermediate concentration（EC50）of compound 1j-1q against rice sheath blight pathogen is lower than that of the control drug osthole（9.8 μg·mL-1）.And boscalid（11.5μg·mL-1）,the activity of compound lo is optimal,and the EC50 can reach 1.4 μg·mL-1.