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Preparation method of 3-difluoro-methyl pyrazole-4-carboxylic acid and 3-trifluoro-methyl pyrazole-4-carboxylic acid

A methylpyrazole and difluoromethyl technology is applied in the field of preparation of 3-difluoromethylpyrazole-4-carboxylic acid and 3-trifluoromethylpyrazole-4-carboxylic acid, and can solve the problem of selection Poor performance, waste of fluorine source, strict requirements for reaction equipment, etc.

Active Publication Date: 2012-10-10
LANZHOU CHEMSPECWEIER CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The excessive fluorinating reagent used leads to a great waste of fluorine source, and the high-pressure reaction conditions lead to harsh requirements for reaction equipment
[0011] In addition, existing patents use ester groups as raw materials, resulting in poor selectivity in the ring-closure reaction of methyl traps. The main product 3-dichloromethyl-1H-methylpyrazole-4-carboxylate and the by-product 5-di The ratio of chloromethyl-1H-methylpyrazole-4-carboxylate is only 81.4:18.6

Method used

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  • Preparation method of 3-difluoro-methyl pyrazole-4-carboxylic acid and 3-trifluoro-methyl pyrazole-4-carboxylic acid
  • Preparation method of 3-difluoro-methyl pyrazole-4-carboxylic acid and 3-trifluoro-methyl pyrazole-4-carboxylic acid
  • Preparation method of 3-difluoro-methyl pyrazole-4-carboxylic acid and 3-trifluoro-methyl pyrazole-4-carboxylic acid

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Embodiment approach

[0141] The present invention provides a preferred embodiment, the method for preparing 3-difluoromethyl-1H-methylpyrazole-4-carboxylic acid and 3-trifluoromethyl-1H-methylpyrazole-4-carboxylic acid comprises the following Steps: one is the reaction of acid chloride (Ⅲ) and compound 3-amino-acrylonitrile (Ⅳ) under the action of a base to generate compound 2-polyhaloacyl-3-amino-acrylonitrile (Ⅴ); the other is compound 2- Polyhaloacyl-3-amino-acrylonitrile (Ⅴ) reacts with methylhydrazine to generate compound 3-polychloromethyl-1H-pyrazole-4-nitrile (Ⅵ); the third is compound 3-polychloro Substituted methyl-1H-pyrazole-4-nitrile (VI) reacts with HF to generate compound 3-polyfluoromethyl-1H-pyrazole-4-nitrile (VII); the fourth is compound 3-polyfluoro Substituted methyl-1H-pyrazole-4-carbonitrile (VII) is hydrolyzed in an aqueous solution of inorganic acid or alkali to prepare 3-difluoromethyl-1H-methylpyrazole-4-carboxylic acid (I) or 3-trifluoromethyl-1H-methylpyrazole-4-carbo...

Embodiment 1-1

[0194] Preparation of 2-dichloroacetyl-3-dimethylamino-acrylonitrile

[0195] Dissolve 26g of 3-dimethylaminoacrylonitrile in 150ml of toluene, add 30.2g of 2,6-lutidine, cool to an internal temperature of 0-10°C, start to add 47.5g of dichloroacetyl chloride dropwise for about one hour Finish. After the dropwise addition, react for another 2 hours. After the reaction is completed, add water, separate the liquid, and concentrate the organic phase to obtain 56 g of the product 2-dichloroacetyl-3-dimethylamino-acrylonitrile. The GC purity is 98.8%, and the yield is 97.0%. .

Embodiment 1-2

[0197] Preparation of 2-dichloroacetyl-3-diethylamino-acrylonitrile

[0198] Dissolve 34g of 3-diethylaminoacrylonitrile in 150ml of chlorobenzene, add 33.2g of 2-methyl-5-ethylpyridine, cool to an internal temperature of -20-0°C, and start to add 47.5g of dichloroacetyl chloride dropwise, about The dropwise addition was completed in one hour. After the dropwise addition, react for another 2 hours. After the reaction is completed, add water, separate the liquid, and concentrate the organic phase to obtain 56 g of the product 2-dichloroacetyl-3-diethylamino-acrylonitrile, with a GC purity of 99.6% and a yield of 95.0%. .

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Abstract

The invention provides a preparation method of 3-difluoro-methyl-1H-methyl pyrazole-4-carboxylic acid shown in the formula (I) or 3-trifluoro-methyl-1H-methyl pyrazole-4-carboxylic acid shown in the formula (II), and the method comprises the following steps of: (a) providing a 3-polyfluoro methyl-1H-pyrazole-4-nitrile group shown in the formula (VII); and (b) under the condition of participation of acid or alkaline, carrying out hydrolysis reaction on the 3-polyfluoro methyl-1H-pyrazole-4-nitrile group shown in the formula (VII), thus obtaining the 3-difluoro-methyl-1H-methyl pyrazole-4-carboxylic acid shown in the formula (I) or 3-trifluoro-methyl-1H-methyl pyrazole-4-carboxylic acid shown in the formula (II).

Description

technical field [0001] The present invention relates to the preparation method of compound 3-difluoromethyl-1H-methylpyrazole-4-carboxylic acid and compound 3-trifluoromethyl-1H-methylpyrazole-4-carboxylic acid. Background technique [0002] Pyrazole amide structure is an important species of fungicides. 3-Difluoromethyl-1H-methylpyrazole-4-carboxylic acid is a common intermediate of the fungicide Bixafen developed by Bayer and Isopyrazam developed by Syngenta; 3-trifluoromethyl-1H-methyl Pyrazole-4-carboxylic acid is an intermediate of the fungicide penthiopyrad developed by Mitsui Chemicals. [0003] In the prior art, Mitisui's patented method (US2010016612) uses difluoroacetic acid or trifluoroacetic acid as a raw material, under the action of oxalyl chloride or triphosgene, undergoes an addition and elimination reaction with 3-aminoacrylonitrile, and then reacts with methyl hydrazine The reaction proceeds to cyclization and finally hydrolysis to obtain the correspondin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D231/14
Inventor 蔡国荣李功勇李文强顾竞王磊杨建华
Owner LANZHOU CHEMSPECWEIER CHEM CO LTD
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