Synthesis and preparation method of 4-pyrazole ethyl formate

A technology of ethyl pyrazole carboxylate and ethyl acrylate, which is applied in the field of synthesis and preparation of ethyl 4-pyrazole carboxylate, can solve the problems of harsh reaction conditions and high cost, and achieve simple preparation process, low production cost and wide source of raw materials Effect

Inactive Publication Date: 2021-03-12
南京麦瑞米生物技术有限公司
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  • Abstract
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  • Application Information

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Problems solved by technology

[0003] The object of the present invention is to provide a kind of synthetic preparation method of ethyl 4-pyrazole carboxylate, to solve the harsh reaction conditions in the prior art, the defective that cost is high

Method used

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Examples

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preparation example Construction

[0023] A kind of synthetic preparation method of ethyl 4-pyrazole carboxylate, described method comprises the steps:

[0024] Step 1: Dissolve ethyl 2-dichloroacetyl-3-(dimethylamino)acrylate in an organic solvent and react with methylhydrazine to obtain 1-methyl-3-dichloromethyl-4-pyrazole Ethyl formate:

[0025] Dissolve ethyl 2-dichloroacetyl-3-(dimethylamino)acrylate in an organic solvent, and react with methylhydrazine. During the reaction, the temperature is controlled at -50-30°C, and the time is 2-10h. The reaction ends Afterwards, 1-methyl-3-dichloromethyl-4-pyrazolecarboxylic acid ethyl ester was obtained;

[0026] Described organic solvent comprises one or more in toluene, benzene, methylene chloride, sherwood oil, various alkanes, xylene, cyclohexane and methylcyclohexane;

[0027] Step 2: react the obtained 1-methyl-3-dichloromethyl-4-pyrazolecarboxylic acid ethyl ester with a fluorinating reagent to obtain 1-methyl-3-difluoromethyl-4-pyrazolecarboxylic acid eth...

Embodiment 1

[0038] Take 1mol of 2-dichloroacetyl-3-(dimethylamino)ethyl acrylate and 1mol of methylhydrazine and dissolve them in 10ml of toluene solution. During the reaction, the temperature is controlled at -50°C and the time is 2h. After the reaction, 1- Ethyl methyl-3-dichloromethyl-4-pyrazolecarboxylate;

[0039] Place the obtained ethyl 1-methyl-3-dichloromethyl-4-pyrazolecarboxylate and 2mol antimony fluoride in a reaction kettle, add 50ml N,N-dimethylformamide to dissolve, and control the reaction temperature to 90°C, the reaction time is 1h, and ethyl 1-methyl-3-difluoromethyl-4-pyrazolecarboxylate is obtained after the reaction;

[0040] After mixing the obtained ethyl 1-methyl-3-difluoromethyl-4-pyrazolecarboxylate and 2mol glacial acetic acid, add 3mol hydrochloric acid solution dropwise at zero degrees Celsius, and slowly stir for 0.5h;

[0041] Add 2 mol of dichloromethane and 10 ml of water into the solution and stir for 1 h, and obtain an organic layer after layering;

...

Embodiment 2

[0044] Take 1mol of 2-dichloroacetyl-3-(dimethylamino)ethyl acrylate and 1mol of methylhydrazine and dissolve them in 10ml of dichloromethane solution. During the reaction, the temperature is controlled at 0°C and the time is 6h. After the reaction, 1 - ethyl methyl-3-dichloromethyl-4-pyrazolecarboxylate;

[0045] Place the obtained ethyl 1-methyl-3-dichloromethyl-4-pyrazolecarboxylate and 2mol potassium fluoride in a reaction kettle, add 50ml N,N-dimethylacetamide to dissolve, and control the reaction temperature to 150°C, the reaction time is 3h, and 1-methyl-3-difluoromethyl-4-pyrazolecarboxylic acid ethyl ester is obtained after the reaction;

[0046] After mixing the obtained ethyl 1-methyl-3-difluoromethyl-4-pyrazolecarboxylate and 2mol glacial acetic acid, add 3mol nitric acid solution dropwise at zero degrees Celsius, and slowly stir for 0.8h;

[0047] Add 2mol dichloromethane and 10ml water to the solution and stir for 2h, and obtain an organic layer after layering; ...

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Abstract

The invention discloses a synthesis and preparation method of 4-pyrazole ethyl formate. The method comprises the following steps: dissolving ethyl 2-dichloroacetyl-3-(dimethylamino) acrylate in an organic solvent, and reacting with methylhydrazine to obtain ethyl 1-methyl-3-dichloromethyl-4-pyrazole formate; reacting the obtained ethyl 1-methyl-3-dichloromethyl-4-pyrazole formate with a fluorination reagent to obtain 1-methyl- 3-difluoromethyl-4-pyrazole ethyl formate; mixing 1-methyl- 3-difluoromethyl-4-pyrazole ethyl formate with glacial acetic acid, dropwise adding a strong acidic solutionat the temperature of 0 DEG C, and then adding dichloromethane and water for stirring and layering to obtain an organic layer; and recrystallizing the organic layer by using a mixed solvent of petroleum ether and ethyl acetate to obtain the 4-pyrazole ethyl formate. The method has the advantages of wide raw material source, low raw material price and simple preparation process, and the obtained product is easy to purify, low in production cost and suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to the technical field of preparation of chemical products, in particular to a synthesis and preparation method of ethyl 4-pyrazolecarboxylate. Background technique: [0002] Ethyl 4-pyrazolecarboxylate is an organic synthesis intermediate and pharmaceutical intermediate, which can be used in the laboratory research and development process and biochemical production process, as well as the preparation of new pesticides. There are also many studies on the synthesis of 4-pyrazole ethyl carboxylate at present, but there are some disadvantages, such as low purity, complicated follow-up treatment, low yield, etc., improving the synthetic process of 4-pyrazole carboxylate ethyl has important social benefit. The traditional synthesis method uses 4-methylpyrazole as a raw material, and potassium permanganate is used to oxidize methyl groups to form carboxyl groups. The raw materials for this reaction are rare and expensive. With 4-bromo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D231/14
CPCC07D231/14
Inventor 廖明
Owner 南京麦瑞米生物技术有限公司
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