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A kind of preparation method of pyrazole carboxylic acid derivative

A technology of ethylene derivatives and methyl groups, applied in the field of preparation of pyrazole formic acid derivatives, can solve problems such as toxicity, non-compliance with environmental protection requirements, use of toxic raw materials, etc.

Active Publication Date: 2017-04-05
ZHEJIANG YONGTAI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to its toxicity, dialkyl sulfate is difficult to apply on a large scale in large factories.
[0004] Chinese patent CN101044116A uses trialkyl phosphate to replace highly toxic dialkyl sulfate, but it needs to be reacted at a high temperature of 180-200°C for 18-24 hours, and post-treatment produces a large amount of waste water, which does not meet environmental protection requirements
But the ethyl 4,4-difluoro-3-oxobutyrate used is expensive and the yield is less than 70%
[0006] The above existing processes all have problems such as the use of toxic raw materials, difficult waste disposal and environmental pollution.

Method used

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  • A kind of preparation method of pyrazole carboxylic acid derivative
  • A kind of preparation method of pyrazole carboxylic acid derivative
  • A kind of preparation method of pyrazole carboxylic acid derivative

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0071] Example 1: Synthesis of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid

[0072]

[0073] Put 70g (0.48mol) of N-1,1,2,2-tetrafluoroethyldimethylamine and 300g of acetonitrile into a 1000ml four-necked bottle equipped with a stirring device and a thermometer, and then add BF dropwise at 20°C 3 Acetonitrile solution 150g (which contains 1.2 equivalents of BF with respect to the N-1,1,2,2-tetrafluoroethyldimethylamine used 3 ), the dropping time is 15-30min, stirring for 30min. 81.8 g (0.58 mol) of N,N-dimethyl-2-(2-methyl-1,3-dioxobutan-2-yl)-ethylene was added dropwise, and the addition was completed within 30 minutes. The reaction was incubated at 20°C for 2 hours. After the heat preservation is completed, the temperature is lowered to about 5°C, and the acetonitrile solution of methylhydrazine (which contains 1.1 equivalent of hydrazine relative to the 1,5-diazapentadiene salt) is added dropwise, and the dropwise addition is completed in about 30 minutes....

Embodiment 2

[0082] Example 2: Synthesis of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid

[0083]

[0084] 73 g (0.50 mol) of N-1,1,2,2-tetrafluoroethyldimethylamine and 300 g of acetonitrile were put into a 1000 ml four-necked bottle equipped with a stirring device and a thermometer. Add BF dropwise at 0°C 3 180 g of acetonitrile solution (with respect to the N-1,1,2,2-tetrafluoroethyldimethylamine used, containing 1.3 equivalents of BF 3 ), the dropping time is 15-30min. Stir at room temperature for 30 minutes. 78 g (0.55 mol) of N,N-dimethyl-2-(2-methyl-1,3-dioxobutan-2-yl)-ethylene was added dropwise, and the addition was completed within 30 minutes. The reaction was incubated at 30°C for 2 hours. After the heat preservation is over, the temperature is lowered to about 5°C. Add the acetonitrile solution of methylhydrazine dropwise (which contains 1.1 equivalent of hydrazine relative to the 1,5-diazapentadienyl salt), and the dropwise addition is completed in about 30...

Embodiment 3

[0089] Example 3: Synthesis of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid

[0090]

[0091] In addition to using 0.58mol of N,N-dimethyl-2-(1,3-dioxobutan-2-yl)-ethylene instead of N,N-dimethyl-2-(2- Methyl-1,3-dioxobutane-2-yl)-ethylene, repeat Example 1 to prepare 3-(difluoromethyl)-1-methyl-4-(2-methyl-1, 3-dioxobutan-2-yl)-1H-pyrazole, and the molar yield was calculated based on N-1,1,2,2-tetrafluoroethyldimethylamine, and the yield was 90.0%. The resulting product is 1 H NMR analysis, elemental analysis and mass spectrometry analysis, it can be determined that the resulting product is 3-(difluoromethyl)-1-methyl-4-(1,3-dioxobutane-2-yl)-1H-pyrazole .

[0092]

[0093] And the elemental analysis and mass spectrometry results of product are as follows:

[0094] Mass spectrometry: m / z: 190.06 (100.0%), 191.06 (7.7%).

[0095] Elemental analysis: C, 44.22; H, 4.24; F, 19.98; N, 14.73; O, 16.83.

[0096] Using 3-(difluoromethyl)-1-methyl-4-(1,3-dioxobu...

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Abstract

The invention relates to a preparation method for a compound of the following formula (I) (please see the formula in the specification). A novel intermediate shown as the following formula (II) (please see the formula in the specification) is used for the method. The method suitable for the synthetic pyrazolecarboxylic acid derivative industrially produced is provided, the reaction yield of each step of the method is high, waste gas and waste water are little, cost is low, and no special reaction devices are needed.

Description

technical field [0001] The invention relates to a preparation method of pyrazole carboxylic acid derivatives. Background technique [0002] Pyrazole carboxylic acid derivatives, such as 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid are key intermediates for the preparation of pesticide fungicides. [0003] Document JP-2000-044541 reports that in the presence of a base, the corresponding substituted pyrazoles are N-methylated with dialkyl carboxylates such as dimethyl sulfate and diethyl sulfate to obtain N-substituted pyrazoles, and then After a series of reactions, pyrazole carboxylic acid derivatives are obtained. However, dialkyl sulfate is difficult to apply on a large scale in large factories due to its toxicity. [0004] Chinese patent CN101044116A uses trialkyl phosphate to replace highly toxic dialkyl sulfate, but it needs to be reacted at a high temperature of 180-200°C for 18-24 hours, and post-treatment produces a large amount of waste water, which doe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D231/14C07D405/04
CPCC07D231/14C07D405/04
Inventor 邵鸿鸣何人宝金逸中王雷
Owner ZHEJIANG YONGTAI TECH CO LTD