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Preparation method of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid

A kind of technology of difluoromethyl and dimethylamino, applied in the field of preparation of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid

Pending Publication Date: 2022-01-11
NANTONG BAOKAI CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, in recent years, due to the long-term use of traditional fungicides, the problem of fungicide resistance has become increasingly prominent. Therefore, it is very important to find new mechanisms of action to develop existing fungicides to solve existing problems

Method used

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  • Preparation method of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid

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Embodiment

[0013] A preparation method of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid, comprising the steps of:

[0014] Step 1. Synthesis of ethyl 2-difluoroacetyl-3-(dimethylamino)acrylate: put N,N-ethyl dimethylaminoacrylate, triethylamine, and toluene into the reaction kettle, and control the temperature at -5~ At 5°C, add difluoroacetyl chloride dropwise, and stir at room temperature for 3 hours. After the reaction of the raw materials is detected, wash with water, separate layers, and distill under reduced pressure to obtain 2-difluoroacetyl-3-(dimethylamino)acrylic acid Ethyl ester; or, in the step 1, no distillation is required, and the organic phase obtained by layering is directly ring-closed with methylhydrazine.

[0015] Step 2. Synthesis of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid: put methylhydrazine and water into the reaction kettle, control the temperature between -5 and 5°C, and drop 2-difluoroacetyl-3-(dimethylamino)ethyl acrylate, after the...

specific Embodiment

[0017] A preparation method of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid, comprising the steps of:

[0018] Step 1, Synthesis of ethyl 2-difluoroacetyl-3-(dimethylamino)acrylate: put N,N-ethyl dimethylaminoacrylate, triethylamine, toluene into the reaction kettle, N,N-dimethylaminoacrylate The molar ratio of ethyl aminoacrylate to triethylamine is 1:1.2, control the temperature between -5 and 0°C, add difluoroacetyl chloride dropwise, stir at room temperature for 3 hours, and wash with water 3 times after the reaction of raw materials is detected , standing for stratification, the organic phase is subjected to vacuum distillation to obtain 2-difluoroacetyl-3-(dimethylamino)ethyl acrylate;

[0019] Alternatively, the step 1 needs not to be distilled, and the organic phase obtained by stratification is directly ring-closed with methylhydrazine;

[0020] Step 2. Synthesis of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid: put methylhydrazine and water into...

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Abstract

The invention discloses a preparation method of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid. The preparation method comprises the following steps of: a, synthesizing 2-difluoroacetyl-3-(dimethylamino) ethyl acrylate; and 2, synthezing 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid. The product is mainly used for synthesizing fluorine-containing pyrazole amide bactericides, difluoroacetyl chloride is used as a raw material, the obtained yield is high, and the total yield is 85% or above. Isomers can be generated when methylhydrazine is subjected to ring closing, hydrazine hydrate can be used for ring closing, and then methyl is formed by dimethyl carbonate.

Description

technical field [0001] The invention belongs to the technical field of medicinal chemistry, and in particular relates to a preparation method of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid. Background technique [0002] The fluorine-containing pyrazole amide fungicides all contain amide groups in their chemical structure. The newly developed fungicides are derived from group substitution on the basis of existing ones. Nearly 20 fungicides of this type have been developed. Varieties, such as products mainly containing wiltin, fluoramide, fluopyram, thifuramide, etc. as active ingredients, fungicides are used for fungal diseases on many crops, and have become an important class of fungicides in production Variety. However, in recent years, due to the long-term use of traditional fungicides, the problem of fungicide resistance has become increasingly prominent. Therefore, it is very important to find new mechanisms of action to develop existing fungicides to solve ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D231/14
CPCC07D231/14
Inventor 张林林邹学明陈彩艳郭英杰
Owner NANTONG BAOKAI CHEM