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Method for purifying 2-(2-flourine-4-chlorine-5-aminophenyl)-4-difluromethylation-5-methyl-1,2,4-triazole-3-ketone

A technology of aminophenyl and difluoromethyl, which is applied in the field of purification of 2--4--5-methyl-1,2,4-triazol-3-one, can solve the problems of yield reduction, color and The purity is difficult to meet the requirements, the amount of solvent is large, etc., to achieve the effect of simple operation

Inactive Publication Date: 2015-05-06
HEFEI JIUYI AGRI DEV
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Problems solved by technology

[0005] 2-(2-fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1 as disclosed in U.S. Patent US5756755 and "The pesticide Manual" 2000, 12th ed., P141 , The purification method of 2,4-triazol-3-one is recrystallization with ethanol or methanol, but this type of purification method is not suitable for 2-(2-fluoro-4-chloro-5-aminophenyl)-4-difluoro The effect of the crude product with higher content of methyl-5-methyl-1,2,4-triazol-3-one is not bad, but for the crude product with more impurities, its 2-(2-fluoro-4 -Chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1,2,4-triazol-3-ketone product is difficult to meet the color and purity requirements, must go through many times Only by crystallization can the 2-(2-fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1,2,4-triazol-3-one product with higher purity be obtained , the amount of solvent used is very large, and the yield also decreases with the increase of recrystallization times, so the purification cost also increases accordingly
[0006] Another example is the method disclosed in world patent WO 9919308 and "Encyclopedia of World Pesticides" herbicide volume 2002,137-140 is to use eluent to 2-(2-fluoro-4-chloro-5-aminophenyl)-4-di The crude product of fluoromethyl-5-methyl-1,2,4-triazol-3-one is purified by silica gel column chromatography. This method uses silica gel column chromatography, which is only suitable for laboratory-scale preparation and industrial production. It is difficult to achieve in the medium, and the amount of solvent is very large, and the cost is very high

Method used

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  • Method for purifying 2-(2-flourine-4-chlorine-5-aminophenyl)-4-difluromethylation-5-methyl-1,2,4-triazole-3-ketone

Examples

Experimental program
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Effect test

Embodiment 1

[0034] 2-(2-Fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1,2,4-triazole-3- Add 100mL of 1mol / L hydrochloric acid dropwise to 15g of crude ketone under heating and stirring, the product dissolves, add 20mL of ethyl acetate, stir, let stand, separate the lower aqueous phase, add 1.0g of 350 mesh activated carbon, heat, stir and reflux at 100°C for 20min , remove activated carbon by filtration, add 1mol / L NaOH solution dropwise to the filtrate, until no more precipitation occurs, separate to obtain light yellow solid 2-(2-fluoro-4-chloro-5-aminophenyl)-4-difluoro Methyl-5-methyl-1,2,4-triazol-3-one 8.6 g, melting point 128-129°C.

[0035] 2-(2-fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1,2,4-triazole-3- Ketone was detected, and the results showed that its purity was 97.6%, and the yield was 82.0%.

Embodiment 2

[0037] 2-(2-Fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1,2,4-triazole-3- To 15g of crude ketone, add 120mL of 1mol / L hydrochloric acid dropwise under heating and stirring, the product dissolves, add 25mL of ethyl acetate, stir, let stand, separate the lower aqueous phase, add 1.5g of 350 mesh activated carbon, heat, stir and reflux at 100°C for 35min , remove activated carbon by filtration, add 1 mol / L potassium carbonate solution dropwise to the filtrate until no precipitation occurs, and separate to obtain light yellow solid 2-(2-fluoro-4-chloro-5-aminophenyl)-4-di Fluoromethyl-5-methyl-1,2,4-triazol-3-one 9.6 g, melting point 128-129°C.

[0038] 2-(2-fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1,2,4-triazole-3- Ketone was detected, and the results showed that its purity was 98.2%, and the yield was 85.1%.

Embodiment 3

[0040] 2-(2-Fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1,2,4-triazole-3- To 20g of crude ketone, add 125mL of 1mol / L sulfuric acid dropwise to it under heating and stirring, the product dissolves, add 40mL of diethyl ether, stir, let stand, separate the lower aqueous phase, add 1.8g of 250-mesh activated carbon, heat and stir at 80°C for 30min, filter to remove Activated carbon, add 1mol / L NaOH solution dropwise to the filtrate until no more precipitation occurs, and separate to obtain a light yellow solid 2-(2-fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl- 15.0 g of 5-methyl-1,2,4-triazol-3-one, melting point 128-129°C.

[0041] 2-(2-fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1,2,4-triazole-3- Ketone was detected, and the results showed that its purity was 97.8%, and the yield was 88.2%.

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Abstract

The invention provides a method for purifying 2-(2-flourine-4-chlorine-5-aminophenyl)-4-difluromethylation-5-methyl-1,2,4-triazole-3-ketone. The method comprises the following steps: firstly, forming an acid from a crude product; decolorizing; and neutralizing to obtain a pure product. The purification process is free of demands on the purity of the crude product; other purifying auxiliary materials are cheap and available; the purifying steps are simple to operate; and industrial production is easy to achieve.

Description

technical field [0001] The field of organic chemistry of the present invention particularly relates to a kind of purification of 2-(2-fluoro-4-chloro-5-aminophenyl)-4--5-methyl-1,2,4-triazol-3-one method. Background technique [0002] 2-(2-Fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1,2,4-triazol-3-one, a white solid, is a herbicide The mefentrazone-ethyl intermediate has a melting point of 128-129° C., and its structure is shown in formula (I): [0003] [0004] At present, the crude product of 2-(2-fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1,2,4-triazol-3-one is mainly prepared by Purify by recrystallization or silica gel column chromatography: [0005] 2-(2-fluoro-4-chloro-5-aminophenyl)-4-difluoromethyl-5-methyl-1 as disclosed in U.S. Patent US5756755 and "The pesticide Manual" 2000, 12th ed., P141 , The purification method of 2,4-triazol-3-one is recrystallization with ethanol or methanol, but this type of purification method is not su...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D249/12
CPCC07D249/12
Inventor 熊国银沈运河周可祥余正莲赵晓俊
Owner HEFEI JIUYI AGRI DEV
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