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Preparation method of 2-p-chlorobenzyl pyridine

A technology of chlorobenzylpyridine and chlorophenyl, which is applied in the field of preparation of intermediate 2-p-chlorobenzylpyridine, can solve the problems of many steps and high requirements for reaction conditions, and achieve low cost, high product purity and easy industrialization Effect

Inactive Publication Date: 2011-02-09
GUANGXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This traditional preparation method not only has many steps, but also requires high reaction conditions.

Method used

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  • Preparation method of 2-p-chlorobenzyl pyridine
  • Preparation method of 2-p-chlorobenzyl pyridine
  • Preparation method of 2-p-chlorobenzyl pyridine

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Example 1 Preparation of 2-p-chlorobenzylpyridine

[0035] Add 2.46g of 2-pyridinecarboxylic acid into a 100ml reaction flask, then slowly add 10ml of thionyl chloride into the constant pressure dropping funnel, slowly raise the temperature to reflux, and react for 3 hours. Heating was stopped, and the remaining thionyl chloride was recovered under reduced pressure to obtain a dark red solid of 2-pyridinecarbonyl chloride hydrochloride. Add 20ml of chlorobenzene under the condition of ice bath, slowly add 5.34g of aluminum trichloride under stirring, continue to stir after adding, after half an hour, transfer the reaction bottle into an oil bath and slowly heat to about 100°C, and react for 3 hours , stop responding. Recover the remaining chlorobenzene under reduced pressure, and then slowly add ice cubes (made by adding 2ml of concentrated hydrochloric acid to 20ml of water) under ice bath conditions. The reaction is very violent, and ice cubes should be added careful...

Embodiment 2

[0037] Example 2 Preparation of 2-p-chlorobenzylpyridine

[0038] Add 2.46g of 2-pyridinecarboxylic acid into a 100ml reaction flask, then slowly add 10ml of thionyl chloride into the constant pressure dropping funnel, slowly raise the temperature to reflux, and react for 3 hours. Heating was stopped, and the remaining thionyl chloride was recovered under reduced pressure to obtain a dark red solid of 2-pyridinecarbonyl chloride hydrochloride. Add 20ml of chlorobenzene under the condition of ice bath, slowly add 7.24g of aluminum trichloride under stirring, continue to stir after the addition, after half an hour, transfer the reaction bottle to an oil bath and slowly heat to about 108°C, and react for 6 hours , stop responding. Recover the remaining chlorobenzene under reduced pressure, and then slowly add ice cubes (made by adding 2ml of concentrated hydrochloric acid to 20ml of water) under ice bath conditions. The reaction is very violent, and ice cubes should be added car...

Embodiment 3

[0040] Example 3 Preparation of 2-p-chlorobenzylpyridine

[0041]Add 2.46g of 2-pyridinecarboxylic acid into a 100ml reaction flask, then slowly add 10ml of thionyl chloride into the constant pressure dropping funnel, slowly raise the temperature to reflux, and react for 3 hours. Heating was stopped, and the remaining thionyl chloride was recovered under reduced pressure to obtain a dark red solid of 2-pyridinecarbonyl chloride hydrochloride. Add 20ml of chlorobenzene under the condition of ice bath, slowly add 6.7g of aluminum trichloride under stirring, continue to stir after adding, transfer the reaction bottle into an oil bath pot and slowly heat to about 145°C after half an hour, and react for 10 hours , stop responding. Recover the remaining chlorobenzene under reduced pressure, and then slowly add ice cubes (made by adding 2ml of concentrated hydrochloric acid to 20ml of water) under ice bath conditions. The reaction is very violent, and ice cubes should be added caref...

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Abstract

The invention relates to a preparation method of 2-p-chlorobenzyl pyridine, comprising the following steps of: firstly adding chlorobenzene and alchlor to 2-pyridine formyl chloride hydrochloride for reaction so as to obtain 1-(4-chlorphenyl)-1-(2-pyridyl) ketone; and then adding diglycol, hydrazine hydrate and potassium hydroxide to the prepared 1-(4-chlorphenyl)-1-(2-pyridyl) ketone for reaction so as to obtain the 2-p-chlorobenzyl pyridine. The 2-p-chlorobenzyl pyridine produced by the method is used as an intermediate for preparing chlorpheniramine and has high product purity and simple and convenient process, and the chlorpheniramine prepared by using the 2-p-chlorobenzyl pyridine accords with Chinese pharmacopoeia; in addition, the invention has low cost, easy industrialization and outstanding economic benefit and social benefit.

Description

technical field [0001] The invention belongs to the preparation method of the intermediate 2-p-chlorobenzylpyridine of the medicine chlorpheniramine. Background technique [0002] Chlorpheniramine, alias: Chlorpheniramine. It is an antihistamine, mainly used for various allergic diseases, such as insect bites, urticaria, vasodilatory rhinitis, asthma, contact dermatitis, etc. It can also be combined with other Chinese and Western medicines to treat colds and so on. Chlorpheniramine has always occupied an important position in antiallergic drugs by virtue of its strong antiallergic activity and relatively small side effects. [0003] 2-p-chlorobenzylpyridine is an important intermediate for preparing chlorpheniramine, and its related preparation technology has many reports. The traditional preparation method is to use 2-picoline after chlorination with aniline at pH=1 Condensation reaction is carried out at the time to obtain 2-p-aminobenzylpyridine, and then it is reacted...

Claims

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Application Information

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IPC IPC(8): C07D213/26C07D213/38
Inventor 王立升陈志刚杨华周永红
Owner GUANGXI UNIV
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