Preparation method of azoxystrobin intermediate

Abstract

The invention relates to a preparation method of an azoxystrobin intermediate, which efficiently synthesizes the azoxystrobin intermediate by adding a catalyst to the ring-opening and etherification reactions, specifically comprising the following steps: methoxymethylene benzofuran Ketone and dichloropyrimidine are added to sodium methoxide / methanol solution in the presence of a catalyst to carry out ring-opening and etherification reactions to synthesize azoxystrobin intermediate compound B. Compared with the prior art, the invention has the advantages of high efficiency, high yield and the like.

Description

technical field [0001] The invention relates to the preparation of a pesticide intermediate, in particular to a novel and efficient method for preparing an azoxystrobin intermediate. Background technique [0002] Azoxystrobin is currently the largest agricultural fungicide product in the world. It is widely produced and used with broad spectrum and high efficiency. The key intermediate compound B of azoxystrobin is generally synthesized from methoxymethylene benzofuranone (compound A) in sodium methoxide / methanol solution and 4,6-dichloropyrimidine through ring-opening and etherification reaction. At present, most domestic enterprises adopt the method described in patent CN1062139A, that is, from compound A to compound B, directly adding sodium methoxide for ring-opening and etherification reactions without adding any catalyst, but the yield can only be maintained at 60~ About 70%, the reaction produces a large amount of by-products, which directly affects the purification ...

AI Technical Summary

Problems solved by technology

Now most domestic enterprises adopt the method described in patent CN1062139A, that is, compound B is synthesized from compound A to compound B, and sodium methoxide is directly added to the ring-opening and etherification reaction without adding any catalyst. However, the yield can only be maintained at 60-60%. About 70%, the reaction produces a large number of by-products, which directly affects the purification of products in subsequent steps

[0003] Azoxystrobin intermediate B is a very critical intermediate for the synthesis of azoxystrobin. At present, most domestic companies are using the method described in Syngenta's patent CN1062139A, that is, compound A and dichloropyrimidine in an organic solvent at low temperature Slowly add sodium methoxide / methanol solution dropwise to realize continuous ring-opening and etherification of compound A and dichloropyrimidine. The main problems in this method are: 1) The reaction time is long, and it needs to react for 22 hours, which causes this step The energy consumption of reaction production is bigger; 2) this method yield is lower, and yield can only reach about 60~70%; 3) the impurity that produces is difficult to purify, affects product purity; 4) because the yield of this method is lower resulting in higher production costs