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Synthesis method of 3-cloro-5-bromo-2-picolinic acid

A technology of picolinic acid and synthesis method, which is applied in the direction of organic chemistry and can solve problems such as not being able to meet market development requirements

Inactive Publication Date: 2016-01-06
高大元
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

With the rapid development of the national economy, the demand for niacin in the feed and food industry has increased sharply, and the existing production equipment and technology are far from meeting the development requirements of the market

Method used

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  • Synthesis method of 3-cloro-5-bromo-2-picolinic acid

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0019] First, add 35g of 3-aminopyridine to a 1L three-necked flask, and add 300mL of hydrochloric acid with a mass concentration of 60% into the flask, and stir it with a machine to completely dissolve it. Add 100mL of hydrogen peroxide with a mass fraction of 10%, and keep stirring at this temperature for 2h. After stirring, lower the temperature to -5°C, and then add 100g of NaNO 2 , and continue to stir for 25min to obtain a diazonium salt solution; take another 1L three-necked flask, add 20gCuCl, 250mL dichloromethane and 5mL concentrated hydrochloric acid with a mass fraction of 70% to it, and then dissolve the above-mentioned solution under stirring Slowly add the diazonium salt solution into the flask, and control the temperature at 15°C. After the addition is completed, keep stirring at this temperature for 20min, then raise the temperature to 30°C, and continue the reaction for 1h. After the reaction is completed, cool to room temperature and use NaOH solution Adjust...

example 2

[0021] First, add 40g of 3-aminopyridine to a 1L three-necked flask, and add 350mL of hydrochloric acid with a mass concentration of 65% into the flask, stir it mechanically to dissolve it completely, then place it in a water bath, control the temperature at 6°C, and pour it into the flask. Add 105mL of hydrogen peroxide with a mass fraction of 11%, and keep stirring at this temperature for 2.5h. After stirring, lower the temperature to -5°C, and then add 105g of NaNO 2, and continue to stir for 28min to obtain a diazonium salt solution; take another 1L three-neck flask, add 21gCuCl, 275mL dichloromethane and 6mL concentrated hydrochloric acid with a mass fraction of 70% to it, and then dissolve the above-mentioned solution under stirring The obtained diazonium salt solution was slowly added to the flask, and the temperature was controlled at 17°C. After the addition was completed, keep stirring at this temperature for 30 minutes, then raise the temperature to 35°C, and continu...

example 3

[0023] First, add 45g of 3-aminopyridine to a 1L three-necked flask, and add 400mL of hydrochloric acid with a mass concentration of 70% to the flask, stir it mechanically to dissolve it completely, then place it in a water bath, control the temperature at 7°C, and pour it into the flask. Add 110mL of hydrogen peroxide with a mass fraction of 12%, and keep stirring at this temperature for 3h. After stirring, lower the temperature to -5°C, and then add 110g of NaNO 2 , and continue to stir for 30min to obtain a diazonium salt solution; take another 1L three-neck flask, add 22gCuCl, 300mL dichloromethane and 7mL concentrated hydrochloric acid with a mass fraction of 70% to it, and then dissolve the above-mentioned solution under stirring. Slowly add the obtained diazonium salt solution into the flask, and control the temperature at 20°C. After the addition is completed, keep stirring at this temperature for 20-40min, then raise the temperature to 40°C, and continue the reaction f...

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Abstract

The invention discloses a synthesis method of 3-cloro-5-bromo-2-picolinic acid, and belongs to the field of chemosynthesis. According to the method, 3-aminopyridine is used as raw materials; concentrated hydrochloric acid and hydrogen peroxide are added for preparing a diazonium salt solution; CuCl, dichloromethane and concentrated hydrochloric acid are added into a three-mouth flask; the diazonium salt solution is dropwise added into the three-mouth flask; the pH value is regulated; extraction, separation and rotary evaporation are carried out to obtain 2, 3-dichloropyridine; absolute ethyl alcohol is used for dissolution; a hydrazine hydrate solution is dropwise added into the flask; under the nitrogen gas protection, backflow is carried out; 3-cloro-2-cyanopyridine can be obtained; then, through specific conditions, the 3-cloro-2-cyanopyridine is used for producing 3-chloropyridine-2-picolinic acid; then, N-bromo-succinimide is added for performing a bromination reaction to finally obtain the 3-cloro-5-bromo-2-picolinic acid.

Description

technical field [0001] The invention discloses a synthesis method of 3-chloro-5-bromo-2-pyridinecarboxylic acid, which belongs to the field of chemical synthesis. Background technique [0002] 2-, 3-pyridinecarboxylic acid and its derivatives exhibit remarkable physiological activity and are widely used in medicine, agriculture and daily chemicals. 2-Picolinic acid derivatives can be used as intermediates of herbicides and neurological drugs. 3-Picolinic acid is used as vitamins, drugs and plant growth regulators. It is a promising pharmaceutical intermediate and feed additive. It can also be used as a hair accelerator, hair dye and polymer stabilizer, and can be developed as an active group New reactive dyes etc. As a pharmaceutical intermediate, 4-pyridinecarboxylic acid is mainly used to prepare isoniazid (remifen), and it can also be used to synthesize derivatives such as isonicotinoyl hydrazone and esters. [0003] my country began to produce 3-picolinic acid (nicoti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/79C07D213/803
CPCC07D213/79C07D213/803
Inventor 高大元王志慧
Owner 高大元
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