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Method for preparing herbicide bispyribac-sodium through phase transfer catalyst

A technology of phase transfer catalyst and bispyribac, which is applied in the direction of organic chemistry, can solve the problems of restricted application, harsh process conditions, and many reaction steps, and achieve good industrial application prospects, high reaction yield, and good product quality.

Inactive Publication Date: 2016-11-09
ZIBO NAB AGROCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The ester group protection method has many reaction steps, long process flow, harsh conditions, and a large amount of precious metals are used as catalysts, and the yield is low, which restricts the application of this method in industrial production.
Due to the heterogeneous reaction in the non-ester group protection method, the process conditions are harsh and the yield is low

Method used

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  • Method for preparing herbicide bispyribac-sodium through phase transfer catalyst

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Weigh 0.04mol 2,6-dihydroxybenzoic acid, 0.05mol 2-methylsulfonyl-4,6-dimethoxypyrimidine, 0.004mol tetrabutylammonium bromide, and 0.08mol potassium carbonate in a reaction vessel , add 300mL of toluene, heat and reflux for 8-10h, filter after cooling, filter the cake with toluene, dry, mix the obtained solid with 500mL of water, stir, add 30% HCl dropwise until the system pH = 3-4, filter and dry, 15.7 g of off-white solid bispyribac was obtained with a purity of 97% and a yield of 85%.

Embodiment 2

[0022] Weigh 0.04mol 2,6-dihydroxybenzoic acid, 0.05mol 2-methylsulfonyl-4,6-dimethoxypyrimidine, 0.008mol n-butylammonium bromide, and 0.08mol potassium carbonate respectively in a reaction vessel , add 300mL tetrahydrofuran, heat and reflux for 8-10h, filter after cooling, wash the filter cake with toluene, dry, mix the obtained solid with 500mL water, stir, add 30% HCl dropwise until the system pH = 3-4, filter and dry, About 16 g of bispyribac ether was obtained as an off-white solid with a purity of 98% and a yield of 87%.

Embodiment 3

[0024] Weigh 0.04mol 2,6-dihydroxybenzoic acid, 0.05mol 2-chloro-4,6-dimethoxypyrimidine, 0.004mol tetrabutylammonium bromide, and 0.08mol potassium carbonate in a reaction vessel, add 300mL of 1,4-dioxane was heated and refluxed for 8-10h, filtered after the reaction was cooled, the filter cake was washed with toluene, dried, the obtained solid was mixed with 500mL of water, stirred, and 30% HCl was added dropwise until the system pH = 3-4, Filter and dry to obtain about 15.8 g of off-white solid with a purity of 98.5% and a yield of 87%.

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Abstract

The invention relates to a preparation method of herbicidal technical, in particular to a method for preparing a herbicide bispyribac-sodium through a phase transfer catalyst. The method comprises the step that 2-substituted-4,6-dimethoxy pyrimidine and 2,6-dihydroxy-benzoic acid serve as raw materials to react in solvent at the temperature of 0 DEG C to 150 DEG C in the presence of potassium carbonate and a catalyst, and then bispyribac-sodium is prepared. The method is characterized in that the phase transfer catalyst is adopted as the catalyst, and the phase transfer catalyst is a quaternary phosphonium salt or quaternary ammonium salt or polyether phase transfer catalyst. According to the method, bispyribac-sodium is prepared by adopting the phase transfer catalyst, the reaction yield is high and is increased by 10% or above at a time compared with an existing method, and an extremely important significance is achieved on bispyribac-sodium production.

Description

technical field [0001] The invention relates to a method for preparing herbicides, in particular to a method for preparing the herbicide bispyribac by using a phase transfer catalyst. Background technique [0002] Bispyribac is a pyrimidine carboxylic acid post-emergence herbicide for rice fields developed by Japan Combination Chemicals Co., Ltd. As a herbicide for rice, it has extremely high herbicidal activity against paddy field weeds at a low dose, and has a wide herbicidal spectrum, and has high safety for direct-seeding rice. [0003] According to current literature reports, there are two main synthesis methods of bispyribac: non-ester group protection method and ester group protection method. The non-ester group protection method is to generate bispyribac from the reaction of 2,6-dihydroxybenzoic acid and 2-substituted-4,6-dimethoxypyrimidine under alkaline conditions, in which the 2-substituent is halogen or methanesulfonate Acyl. The ester group protection rule i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D239/60
CPCC07D239/60
Inventor 郑有奎宋君王晓伟
Owner ZIBO NAB AGROCHEM
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