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Method for preparing bensulfuron methyl

A technology of bensulfuron-methyl and methyl benzsulfonamide, which is applied in the field of synthesis of the pesticide bensulfuron-methyl, and can solve the problems of low yield, low content and unstable intermediates of bensulfuron-methyl

Active Publication Date: 2012-11-28
JIANGSU TIANRONG GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This process isocyanate 2-amino-4,6-dimethoxypyrimidine, the reaction yield is low, and the intermediate is unstable, resulting in low yield and low content of the final condensed bensulfuron-methyl

Method used

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  • Method for preparing bensulfuron methyl
  • Method for preparing bensulfuron methyl
  • Method for preparing bensulfuron methyl

Examples

Experimental program
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Effect test

Embodiment 1

[0031] Put 50 grams (98%) of methyl o-formate benzylsulfonamide, 12 grams of n-butyl isocyanate, 300 ml of xylene and 35 grams of bis(trichloromethyl)carbonate (100 percent) into a 500 ml four-necked reaction flask, stir Accompanied by raising the temperature to 80°C, start to heat up at a rate of 0.5°C / min, and keep warm for 10 minutes every time the temperature rises by 10°C. When the temperature rises to 120°C, add 7 grams of trichloromethyl chloroformate dropwise, and keep warm for 2 to 3 hours. After the heat preservation is over, remove the solvent by distillation under reduced pressure, keep a vacuum of -0.09MPa during distillation, evaporate the solvent to dryness, add 70ml of toluene, cool to 40°C, add 31 grams of 2-amino-4,6-dimethoxypyrimidine evenly, The temperature was raised to 70°C, stirred for 1 hour, cooled to room temperature, centrifuged at high speed, and dried to obtain bensulfuron-methyl, with a weight of 86.3 g, a mass content of 97.2%, and a molar yield ...

Embodiment 2

[0033] Put 50 grams (98%) of methyl o-formate benzylsulfonamide, 12 grams of n-butyl isocyanate, 300 ml of xylene and 37 grams of bis(trichloromethyl)carbonate (100 percent) into a 500 ml four-necked reaction flask, stir Accompanied by raising the temperature to 80°C, start to heat up at a rate of 0.5°C / min, and keep warm for 10 minutes every time the temperature rises by 10°C. When the temperature rises to 120°C, add 5 grams of trichloromethyl chloroformate dropwise, and keep warm for 2 to 3 hours. After the heat preservation is over, remove the solvent by distillation under reduced pressure, keep a vacuum of -0.09MPa during distillation, evaporate the solvent to dryness, add 70ml of toluene, cool to 40°C, add 30g of 2-amino-4,6-dimethoxypyrimidine evenly, The temperature was raised to 70°C, stirred for 1 hour, cooled to room temperature, centrifuged at high speed, and dried to obtain bensulfuron-methyl, with a weight of 86.2 g, a mass content of 97.1%, and a molar yield of 90...

Embodiment 3

[0035] Put 50 grams (98%) of methyl o-formate benzylsulfonamide, 12 grams of n-butyl isocyanate, 300 ml of xylene and 37 grams of bis(trichloromethyl)carbonate (100 percent) into a 500 ml four-necked reaction flask, stir Accompanied by raising the temperature to 80°C, start to heat up at a rate of 0.5°C / min, and keep warm for 10 minutes every time the temperature rises by 10°C. When the temperature rises to 120°C, add 5 grams of trichloromethyl chloroformate dropwise, and keep warm for 2 to 3 hours. After the heat preservation is over, remove the solvent by distillation under reduced pressure, keep a vacuum of -0.09MPa during distillation, evaporate the solvent to dryness, add 50ml of acetonitrile, cool to 40°C, and evenly add 29 grams of 2-amino-4,6-dimethoxypyrimidine, The temperature was raised to 70°C, stirred for 1 hour, cooled to room temperature, centrifuged at high speed, and dried to obtain bensulfuron-methyl, with a weight of 85.2 g, a mass content of 98.0%, and a mol...

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Abstract

The invention discloses a method for preparing bensulfuron methyl. The method comprises the following steps of: mixing o-methyl formate benzyl sulfamide, bis(trichloromethyl) carbonate and normal-butyl isocyanate serving as a catalyst in dimethylbenzene, heating to the temperature of between 70 and 85 DEG C, heating to the temperature of between 110 and 130 DEG C slowly, adding trichloromethyl chloroformate slowly at the temperature of between 110 and 130 DEG C, performing esterification reaction at the temperature of between 110 and 130 DEG C, and removing a solvent and the catalyst after reaction; and adding o(methyl formate) benzyl sulfonyl isocyanate obtained by the esterification reaction into a condensation reaction solvent, stirring, cooling to the temperature of between 30 and 50 DEG C, continuing to add 2-amino-4,6-dimethoxy pyrimidine, performing condensation reaction at the temperature of between 50 and 90 DEG C, cooling, and drying to obtain the bensulfuron methyl. By the method, the bensulfuron methyl of which the content is more than 97 percent can be obtained, and the total yield is more than 90 percent.

Description

technical field [0001] The invention belongs to the field of pesticide synthesis, in particular to a method for synthesizing the pesticide bensulfuron-methyl. Background technique [0002] The pure product of bensulfuron-methyl is a white solid, and the industrial product is a light yellow solid. It is a new type, broad-spectrum, high-efficiency, low-toxicity, and safe paddy field herbicide, belonging to the sulfonylurea class. The herbicide has minimal impact on environmental quality, is safe for humans and animals, has no teratogenic or mutagenic phenomena, and has a wide range of applications. It can be used not only in direct-seeding fields, seedling fields, but also in transplanting fields; the dosage is extremely low, about 0.1-0.2g (a.i) / ha dose can effectively control most broad-leaved weeds and sedge weeds; it can be used alone or in combination. [0003] Its synthesis methods are: [0004] Route 1: [0005] [0006] Because route 1 adopts ethyl chloroformate ...

Claims

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Application Information

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IPC IPC(8): C07D239/52
Inventor 许网保魏明阳臧伟新虞国新
Owner JIANGSU TIANRONG GROUP
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