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Nicosulfuron preparation method

A technology of nicosulfuron and sulfonyl chloride, which is applied in the field of herbicide preparation, can solve the problems of high toxicity, high price, and large amount of waste gas, and achieve the effects of mild reaction conditions, short reaction cycle, and high purity

Active Publication Date: 2014-01-22
江苏省农用激素工程技术研究中心有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The disadvantage of the carbamate method is that: the raw material dialkyl (aryl) carbonate (such as diphenyl carbonate, etc.) is expensive, resulting in higher costs; and chloroformate is highly toxic and unsafe to operate
[0009] The disadvantage of the urea method is that a two-step reaction is required, that is, the intermediate 2-ureido-4,6-dimethoxypyrimidine must be separated to enter the next condensation reaction, the reaction cycle is long, and it is not suitable for industrial production
[0011] The disadvantages of the phosgene method are: high toxicity, unsafe operation, large amount of waste gas, and great impact on the environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1）

[0024] The preparation method of the nicosulfuron-methyl of the present embodiment is as follows:

[0025] In a 1000mL reaction flask, add 100g of 2-sulfonyl chloride-N,N-dimethylnicotinamide (0.40mol), 40g of sodium cyanate (0.62mol), 101g of triethylamine (1.00mol) and 125g acetonitrile, the temperature is controlled at 25±5°C, and the isocyanate reaction is carried out with stirring.

[0026] After 5 hours, 75 g of 2-amino-4,6-dimethoxypyrimidine (0.48 mol) was added to the reaction bottle, and the condensation reaction was carried out with stirring at ambient temperature (0-40° C., the same below) for 1 hour.

[0027] After the condensation reaction is over, add 500g of deionized water dropwise to the reaction bottle (about 1.5h), adjust the pH to 1.0 with hydrochloric acid, stir for 1h and then centrifuge, wash and dry the solid to obtain 157.8g The nicosulfuron-methyl, the yield is 92.1%, and the purity is 95.7%.

Embodiment 2～ Embodiment 9）

[0029] The preparation method of each example is basically the same as that of Example 1, the differences are shown in Table 1, wherein aminopyrimidine represents 2-amino-4,6-dimethoxypyrimidine. The reaction temperature and time are the reaction of 2-sulfonyl chloride-N,N-dimethylnicotinamide and sodium cyanate.

[0030] Table 1

[0031] Sodium cyanate temperature reflex Reaction time Aminopyrimidine product weight yield purity Example 1 40g, 0.62mol 25±5℃ 5h 75g, 0.48mol 157.8g 92.1% 95.7% Example 2 32.5g, 0.5mol 25±5℃ 5h 75g, 0.48mol 150.0g 85.5% 93.5% Example 3 45.5g, 0.7mol 25±5℃ 5h 75g, 0.48mol 157.1g 90.8% 94.8% Example 4 40g, 0.62mol 25±5℃ 5h 62g, 0.4mol 152.0 87.6% 94.5% Example 5 40g, 0.62mol 25±5℃ 5h 93g, 0.6mol 156.1 90.9% 95.5% Example 6 40g, 0.62mol 15±5℃ 5h 75g, 0.48mol 155.9 90.5% 95.2% Example 7 40g, 0.62mol 35±5℃ 5h 75g, 0.48mol 156.5 91.3% ...

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Abstract

The invention discloses a nicosulfuron preparation method. According to the invention, in an organic solvent, 2-sulfonyl chloride-N,N-dimethyl nicotinamide and sodium cyanate are subjected to a reaction for 2-10h under stirring under the existence of organic alkali and under a temperature of 10-50 DEG C; 2-amino-4-dimethoxy pyrimidin is added, and a reaction is carried out for 0.5-5h under stirring under an environmental temperature, such that nicosulfuron is obtained. According to the invention, sodium cyanate is subjected to a reaction with 2-sulfonyl chloride-N,N-dimethyl nicotinamide to produce corresponding isocyanate, and isocyanate is subjected to a condensation reaction with 2-amino-4-dimethoxy pyrimidin. The synthetic route has the advantages of mild reaction condition, low cost, high yield, and high purity. The intermediate is not needed to be separated, and reaction period is short, such that the method is suitable for industrialized productions. The method also has the advantages of low toxicity and no environment pollution, such that the method satisfies a green chemistry principle.

Description

technical field [0001] The invention relates to a preparation method of a herbicide, in particular to a preparation method of nicosulfuron. Background technique [0002] The chemical name of nicosulfuron is 2-(4,6 dimethoxypyrimidin-2-ylcarbamoylaminosulfonyl)-N,N-dimethylnicotinamide. It is a novel cornfield herbicide launched by Ishihara Corporation of Japan in 1987. It has a wide herbicidal spectrum, not only has good stem and leaf treatment activity, but also has a certain soil sealing effect, high efficiency, low residue and friendly to the environment. Used to replace the existing herbicides acetochlor and atrazine in cornfields, it not only fundamentally solves the problem of large application amount and high residue of existing herbicides, but also can increase production. An important choice for herbicides. [0003] At present, the preparation methods of nicosulfuron mainly contain the following types: [0004] (1) Carbamate method: using 2-amino-4,6-dimethoxypyr...

Claims

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Application Information

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IPC IPC(8): C07D401/12
CPCC07D401/12
Inventor 孙永辉孔繁蕾史跃平高建红张元元曹伟
Owner 江苏省农用激素工程技术研究中心有限公司
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