Study On Synthesis Of Pyraclostrobin And Cyprodinil Fungicide

Strobilurin fungicide is a kind of new fungicides after triazole fungicises. It is amitochondrial respiration inhibitor and its development is on the basis of the naturalantibiotic compound Strobilurin A. Strobilurin fungicide is a sort of fungicide withbroad spectrum, low toxicity and high efficiency. It has efficient prevention andtreatment effect on almost all the diseases including fungus, deuteromycetes andascomycetes. It has no resistance with other fungicides that have been marketed in ourcountry. Pyraclostrobin is currently the highest activity of Strobilurin fungicides, andits synthesis technology has not been announced. To study its synthesis processes isvery significant for improving the backward structure of pesticides in our country andreducing traditional fungicide pollution to the environment. In this paper, thesynthesis processes of pyraclostrobin was studied and improved. The intermediate1-(4-chlorophenyl)-3-pyrazolidin is made from p-chloroaniline and makes up of foursteps including diazotization, reducyion, acidification and oxidation, and the contentis97.7%（LC）, total yield is60.7%. Then we utilize the o-nitrotoluene as the rawmaterial to prepare the N-methoxy-N-2-bromine toluene methyl carbamate throughreduction, N-acylation, N-methylation and bromination, the compound obtained reactswith the intermediate1-(4-chlorophenyl)-3-pyrazolidin to produce the targetcompound pyraclostrobin, its purity is moer than98.4%and the total yield is morethan56.7%(calculated by o-nitrotoluene), it has improved greatly than the existingliteratures. It has made the optimized improvement for the key step bromination,reduced the by-products, increased the reaction yield, and reduced the cost. Theoperation of the whole reaction processes is simple, and it is suitable for industrializedproduction, and has a very good application prospect.Anilinopyrimdine fungicide has broad spectrum fungicidal activities and aunique mechanism of action. It is a methionine synthesis inhibitor, and mainly used inpathogenic fungus stadium invasionis and hyphal vegetative period. Cyprodinil is akind of anilinopyrimidine fungicides developed by Novartis Company of Switzerland.It is a kind of systemic fungicide with the characteristics of high efficiency, broadspectrum and low toxicity. In this paper, the synthesis processes of cyprodinil wasstudied. Cyprodinil was synthesized through two steps, 1-cyclopropylbutane-1,3-dione was prepared from cyclopropyl methyl ketone reactingwith ethyl acetate through Claisen condensation reaction under the sodium hydridecatalysis, then reacts with1-phenylguanidine through dehydration synthesis. The totalyield is63.5%, the content of the purified product is99.5%(LC). In this paper, thesynthesis processes are simple, raw materials are easy to get and it is suitable forindustrial production, so cyprodinil is a promising fungicide.