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

A technology of methylpyrazole and difluoromethyl 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 reaction Harsh equipment requirements, poor selectivity, waste of fluorine sources, etc.

Active Publication Date: 2015-04-29
LANZHOU CHEMSPECWEIER CHEM CO LTD
View PDF11 Cites 2 Cited by
  • 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

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • 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

Examples

Experimental program
Comparison scheme
Effect test

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%. .

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

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

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Patents(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
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap