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Preparation method of pyrazine carboxylic acid

A technology of pyrazine carboxylic acid and acrylic acid, applied in the direction of organic chemistry and the like, can solve the problems of waste of resources, unfavorable environmental protection production, difficult separation and the like, and achieves the effects of mild conditions and improved yield

Inactive Publication Date: 2016-12-14
天津市亨必达化学合成物有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

It is not conducive to the environmental protection production of enterprises and the sustainable development of the environment
Its two, because the relative positions of the methyl groups of the raw materials are consistent, it is easy to fully oxidize the two methyl groups to generate 2,5-pyrazine dicarboxylic acid by-products, the reaction does not have high selectivity, and the product is different from 2,5-pyrazine Dicarboxylic acid by-products are difficult to separate, and the production yield is low, resulting in waste of resources

Method used

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  • Preparation method of pyrazine carboxylic acid
  • Preparation method of pyrazine carboxylic acid
  • Preparation method of pyrazine carboxylic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Add 20g of acrylic acid and 200mL of dichloromethane to a 500mL three-necked flask in sequence, start stirring, control the temperature at 20-30°C and slowly add 51.1g of bromine dropwise, and the dropwise addition is completed in 15 minutes. Heat to 30-50°C and stir under temperature control for 2 hours, stop heating, add 200mL saturated sodium chloride solution, separate the liquids, and lower the temperature to 0°C. Stir and crystallize for 4h, filter to obtain intermediate (II);

[0031] S2: Add the intermediate (II) obtained in step S1 into 200 mL of absolute ethanol, slowly add 50 mL of ammonia water dropwise at room temperature, react at room temperature for 6 hours, and evaporate the solvent to obtain intermediate (III);

[0032] S3: Add the intermediate (III) obtained in step S2 and 20g of aceglyoxal into a 500mL reaction flask, add 200mL of absolute ethanol, stir to make it completely dissolve; heat up to reflux, reflux for 4h, and evaporate the solvent under ...

Embodiment 2

[0035] Add 20g of acrylic acid and 200mL of dichloromethane to a 500mL three-necked flask in sequence, start stirring, control the temperature at 20-30°C and slowly add 44.4g of bromine dropwise, and the dropwise addition is completed in 10 minutes. Heat to 30°C and stir under temperature control for 2.5h, stop heating, add 200mL saturated sodium chloride solution, separate the liquids, and lower the temperature to 0°C. Stir and crystallize for 3h, filter to obtain intermediate (II);

[0036] S2: Add the intermediate (II) obtained in step S1 into 200 mL of absolute ethanol, slowly add 30 mL of ammonia water dropwise at room temperature, react at room temperature for 5 hours, and evaporate the solvent to obtain intermediate (III);

[0037] S3: Add the intermediate (III) obtained in step S2 and 15g of aceglyoxal into a 500mL reaction flask, add 200mL of absolute ethanol, stir to make it completely dissolve; heat up to reflux, reflux for 3h, and evaporate the solvent under reduce...

Embodiment 3

[0040] Add 20g of acrylic acid and 200mL of dichloromethane to a 500mL three-necked flask in sequence, start stirring, control the temperature at 20-30°C and slowly add 66.7g of bromine dropwise, and the dropwise addition is completed in 20 minutes. Heat to 50°C and stir under temperature control for 1.5h, stop heating, add 200mL of saturated sodium chloride solution, separate the liquids, and lower the temperature to 0°C. Stir and crystallize for 5h, filter to obtain intermediate (II);

[0041] S2: Add the intermediate (II) obtained in step S1 into 200 mL of absolute ethanol, slowly add 100 mL of ammonia water dropwise at room temperature, react at room temperature for 7 hours, and evaporate the solvent to obtain intermediate (III);

[0042] S3: Add the intermediate (III) obtained in step S2 and 30g of aceglyoxal into a 500mL reaction flask, add 200mL of absolute ethanol, stir to make it completely dissolve; heat up to reflux, reflux for 5h, and evaporate the solvent under re...

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Abstract

The invention provides a preparation method of pyrazine carboxylic acid. The method includes the steps of: performing an addition reaction to an initial raw material, acrylic acid, with bromine in dichloromethane; performing a substitution reaction to the addition product with ammonia water in anhydrous ethanol; performing a reaction to the substitution product with methylglyoxal in anhydrous ethanol; and performing DDQ dehydrogenation in dichloromethane to obtain the pyrazine carboxylic acid. In the invention, by changing the synthetic route, an oxidization reaction is avoided smartly, so that risk of explosion is avoided and generation of waste gas and waste water is reduced, thereby preparing the target product under mild conditions. The route also avoids a problem of selectivity, so that yield is increased in another way.

Description

technical field [0001] The invention belongs to the technical field of pharmaceutical chemical synthesis, in particular to a preparation method of pyrazine carboxylic acid. Background technique [0002] Existing preparation structural formula is that the method for the pyrazine carboxylic acid of (I) formula mostly adopts oxidizing agent to directly oxidize p-methylpyrazine to generate pyrazine carboxylic acid, and synthetic route is as follows: [0003] [0004] Most of the oxidants used are potassium permanganate, concentrated nitric acid, concentrated sulfuric acid, etc. There are problems, one: the oxidation reaction itself, there is a risk of explosion. Secondly, when dealing with the oxidation reaction, thiosulfuric acid and the like are often used to form a large amount of waste water. It is not conducive to the environmental protection production of enterprises and the sustainable development of the environment. Its two, because the relative positions of the me...

Claims

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Application Information

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IPC IPC(8): C07D241/24
CPCC07D241/24
Inventor 赵钊汪洋朱云景
Owner 天津市亨必达化学合成物有限公司
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