Quizalofop-p-ethyl as well as synthetic method of intermediate 4-(6-chloro-2 quinoxaline)phenol

Abstract

The invention relates to a synthetic method of quizalofop-p-ethyl. The synthetic method is characterized by comprising the following steps: firstly enabling hydroquinone and sodium hydroxide to reactto prepare a sodium salt of the hydroquinone, then enabling the sodium salt to react with 2,6-dichloro-quinoxaline, obtaining 4-(6-chloro-2 quinoxaline)phenol, and then enabling the 4-(6-chloro-2 quinoxaline)phenol to react with p-toluenesulfonic ethyl lactate to obtain the quizalofop-p-ethyl. The synthetic process optimizes the original process and has the advantage that the reaction and the after-treatment are performed in an organic solvent, so that the alkalinity of a reaction system is reduced, the defect that impurities are likely to generate due to the high reaction alkalinity of a water phase can be avoided, the hydrolysis of the raw material 2,6-dichloro-quinoxaline is reduced, the content of the 4-(6-chloro-2 quinoxaline)phenol is 98 percent or greater, the yield is 92 percent orhigher, and the subsequent synehtic reaction yield reaches 90 percent or greater.

Description

technical field [0001] The invention relates to the technical field of pesticide synthesis, in particular to a method for synthesizing quizalofop-p-ethyl and its intermediate 4-(6-chloro-2quinoxalinyloxy)phenol. Background technique [0002] Quizalofop-ethyl is a post-emergence selective herbicide developed by Nissan Chemical Industry Co., Ltd., Japan. It shows strong killing effect on annual and perennial grass weeds, and is safe for broad-leaved crops. It can be widely used in cotton, rapeseed, The control of gramineous weeds in crops such as peanuts, soybeans and various broad-leaved vegetables, so it has broad prospects for the synthesis of original drugs and the processing of preparations. [0003] At present, there are two synthetic routes for quizalofop-p-ethyl, one is to use 2,6-dichloroquinoxaline as a raw material, the reaction shown in equation 1 occurs, and the direct or re-esterification reaction obtains quizalofop-p-p-p, the other The route is to prepare 4-(6-...

AI Technical Summary

Problems solved by technology

[0009] Up to now, in the prior art, the aqueous phase etherification reaction involving 2,6-dichloroquinoxaline and potassium hydroxide has been mainly introduced. The reaction system is extremely alkaline, and active chlorine in 2,6-dichloroquinoxaline is prone to Hydrolysis affects the yield of etherification reaction. Secondly, due to the high concentration of alkali, two molecules of 2,6-dichloroquinoxaline and one molecule of hydroquinone are generated with more impurities, and the content of etherification products is lower;

[0010] The etherification reaction of 2,6-dichloroquinoxaline and sodium hydroxide in a mixed solvent of toluene and DMF, the reaction uses DMF, which has a strong solubility for the product, and the ratio of 2,6-dichloroquinoxaline to the amount of alkali About 1:5, there are too many bis-ether impurities. In addition, ice water is required for post-treatment. The steps are complicated. The ice water will mix with the solvent and it is difficult to handle, which will affect the solvent recovery.

Images