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A kind of preparation method of 2,6-dimethyl-3,5-dichloro-4-hydroxypyridine

A technology of hydroxypyridine and dimethyl, which is applied in the field of preparation of 2,6-dimethyl-3,5-dichloro-4-hydroxypyridine, can solve the problems of preparation method pollution and achieve simple separation and purification Effects of unit reactions, ease of manipulation, and postprocessing

Active Publication Date: 2018-05-22
INNER MONGOLIA HUATIAN PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a green method for synthesizing 2,6-dimethyl-3,5-dichloro-4-hydroxypyridine, which uses weakly basic ion exchange resin as a catalyst and uses ethyl acetoacetate as a raw material to prepare The method of 2,6-dimethyl-3,5-dichloro-4-hydroxypyridine, which is easy to operate and environmentally friendly, and solves the problem of pollution caused by existing preparation methods

Method used

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  • A kind of preparation method of 2,6-dimethyl-3,5-dichloro-4-hydroxypyridine
  • A kind of preparation method of 2,6-dimethyl-3,5-dichloro-4-hydroxypyridine

Examples

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Embodiment 1

[0019] In a 500 ml three-necked flask, add 130 g (1 mole) of ethyl acetoacetate, 39 g of Styrene-DVB (D301R) resin, react at 60°C for 3 hours, add 100 ml of distilled water, and feed 51 g of ammonia gas under stirring (3 moles), after reacting at 30°C for 5 hours, feed 142 grams (2 moles) of chlorine gas under stirring, react at 30°C for 2 hours, filter, filter out Styrene-DVB (D301R) resin and solids, use for filter cake After washing with 100 ml of NaOH (mass concentration 10%) aqueous solution, the Styrene-DVB (D301R) resin can be recycled. A small amount of ethanol was distilled off from the filtrate, and the crystals were precipitated after standing, filtered, and dried to obtain 87.4 g of the target product, with a yield of 91%. Melting point: 265-268°C. HRMS (ESI): m / e=192 (M + ).

Embodiment 2

[0021] In a 500 ml three-necked flask, add 130 g (1 mole) of ethyl acetoacetate, 39 g of Styrene-DVB (D301T) resin, react at 30°C for 5 hours, add 100 ml of distilled water, and feed 85 g of ammonia gas under stirring (5 moles), after reacting for 2 hours at 10 DEG C, feed 142 grams (2 moles) of chlorine gas under stirring, react for 2 hours at 30 DEG C, filter out Styrene-DVB (D301T) resin and solid, filter cake with NaOH ( The Styrene-DVB (D301T) resin can be recycled after washing with 100 milliliters of an aqueous solution with a mass concentration of 10%. A small amount of ethanol was distilled off from the filtrate, and the crystals were precipitated after standing, filtered, and dried to obtain 87.8 g of the target product, with a yield of 91.5%. Melting point: 265-268°C. HRMS (ESI): m / e=192 (M + ).

Embodiment 3

[0023] In a 500 ml three-necked flask, add 130 grams (1 mole) of ethyl acetoacetate, 39 grams of Styrene-DVB (D301G) resin, react at 60 ° C for 3 hours, add 100 ml of distilled water, and feed 34 grams of ammonia gas under stirring (2 moles), after reacting at 30 DEG C for 5 hours, feed 71 grams (1 moles) of chlorine gas under stirring, react at 10 DEG C for 1 hour, filter out Styrene-DVB (D301G) resin and solid, filter cake with NaOH ( After washing with 100 milliliters of an aqueous solution with a mass concentration of 10%, the Styrene-DVB (D301G) resin can be recycled. A small amount of ethanol was distilled off from the filtrate, and crystals were precipitated after standing, filtered, and dried to obtain 87.0 g of the target product, with a yield of 90.6%. Melting point: 265-268°C. HRMS (ESI): m / e=192 (M + ).

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Abstract

The invention discloses a preparation method of 2,6-dimethyl-3,5-dichloro-4-hydroxypyridine. The method uses ethyl acetoacetate as a raw material and a weakly basic ion exchange resin as a catalyst. Carry out the dimerization reaction at 25-90°C. After the reaction is over, add water and pass through ammonia gas for ammoniation at 10-45°C, then pass through chlorine gas for chlorination at 10-45°C, and post-treat the reaction liquid. Obtain 2,6-dimethyl-3,5-dichloro-4-hydroxypyridine; the present invention uses weakly basic ion-exchange resin as a catalyst, uses ethyl acetoacetate as a raw material, and adopts series technology to prepare the target product, which simplifies Unit reaction, easy to operate and post-treatment in the production process. After the reaction, only need to filter the reaction solution, recover the catalyst from the filter cake, and recrystallize the filtrate to obtain the product. The yield is 91.5%. The separation and purification of the product is simple and pollution-free , is a green preparation method.

Description

(1) Technical field [0001] The present invention relates to a kind of preparation method of 2,6-dimethyl-3,5-dichloro-4-hydroxypyridine, especially a kind of preparation method of ethyl acetoacetate under the action of D301 type weak basic anion exchange resin catalyst A method for the preparation of 2,6-dimethyl-3,5-dichloro-4-hydroxypyridine using a series reaction technique. (2) Background technology [0002] 2,6-Dimethyl-3,5-dichloro-4-hydroxypyridine is white or off-white powder, odorless. This product is very slightly soluble in methanol or ethanol, insoluble in water, acetone, ether or benzene; slightly soluble in sodium hydroxide test solution. Molecular formula C 7 h 7 Cl 2 NO, molecular weight 192.04, melting point 264-270°C. This product is a special-effect feed additive for chicken coccidiosis and Leukocytozoon cariniiosis created by American Dow Chemical Company. Improve feed utilization. At present, the synthesis method of 2,6-dimethyl-3,5-dichloro-4-hyd...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/68
CPCY02P20/584
Inventor 裴文孙莉赵典林韩宜廷孙文
Owner INNER MONGOLIA HUATIAN PHARMA
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