Synthesis method of pyraclostrobin

Abstract

The invention aims at providing a synthesis method of pyraclostrobin. The method comprises the following steps: with chloroaniline and ortho-nitrotoluene as raw materials, synthesizing, cyclizing, oxidizing, bromizing, etherifying, reducing, esterifying and methylating chlorophenylhydrazine hydrochloride to prepare the pyraclostrobin. The purity of the pyraclostrobin synthesized through the method disclosed by the invention is 98.0% and more, the yield reaches 48%. And the process is low in cost, simple to operate and easy for industrial production.

Description

technical field [0001] The invention relates to the field of pesticide fungicides, in particular to a method for synthesizing pyraclostrobin. Background technique [0002] Pyraclostrobin, also known as pyraclostrobin, is a broad-spectrum fungicide of methyl methoxyacrylate with a pyrazole structure discovered by BASF in 1993, with molecular formula C 19 h 18 ClN 3 o 4 , whose structure is [0003] [0004] Pyraclostrobin has patent rights in the United States, Europe and other countries, and has also applied for a patent in my country, but its synthesis technology has not yet been disclosed. At present, the synthetic route of pyraclostrobin at home and abroad can be divided into the following two types: the first condensation method and the post-condensation method, both of which are based on o-nitrotoluene and p-chloroaniline as starting materials. The first condensation method is to prepare pyraclostrobin through the eight-step reaction of p-chlorophenylhydrazine h...

AI Technical Summary

Problems solved by technology

The first condensation method is to prepare pyraclostrobin through the eight-step reaction of p-chlorophenylhydrazine hydrochloride synthesis, cyclization, oxidation, bromination, etherification, reduction, esterification and methylation. The yield is high, and the conditions are relatively mild; the post-condensation method is to prepare pyraclofenac by synthesis, cyclization, oxidation, reduction, esterification, methylation, bromination and condensation reactions of p-chlorophenylhydrazine hydrochloride ester, but the yield of the reduction of o-nitrotoluene to hydroxylamine in this method is low, the condensation yield in the last step is low, and the final product is difficult to purify

At present, the key problem in the synthesis route of pyraclostrobin is the key steps of reduction and bromination reactions, the reaction is easy to produce by-products, and the separation is quite difficult

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