Study On The Synthetic Technology Of Novel Fungicides-Pyraclostrobin

Strobilurin fungicides based natural antibiotic Strobilurin A is a novel fungicide,it is a sort of fungicides with low toxicity and high activity,broad spectrum.Strobilurin fungicides has the features of protection,cure,penetration and it is safe to environment because it can rapidly degradate in plants,soil and water.Thus,strobilurin fungicides that develop in ten just years had become a mainstream products of agricultural fungicides,its market sales had been more than triazole fungicides and being first of the various types of fungicides.In this thesis,the synthesis processes of the strobilurin fungicide pyraclostrobin has been researched.The optimum synthetic route is made from 4-chlorophenylhy-drazine hydrochloride and 2-melhylnitrobenzene and make up of seven steps including cyclization,oxidation,bromination,condensation,reduction,acylation and methylation by summarizing a mass of literatures.After a large number of experiments to determine the optimal reaction conditions,comparing the merits of all kinds of bromide methods to select the best one,and determine the best bromination conditions.We used autoclave to da the reduction reaction,focused on the influence of pressure,temperature,catalyst.The two improvements of synthetic technology has greatly increased the yield of the pyraclostrobin,the total yield is 48%.The structure of pyraclostrobin is listed as follows:The chemical structures of pyraclostrobin and intermediate were confirmed by IR,1H NMR,GC-MS,HPLC.The spectroscopic properties of these compounds were also discussed.