Preparation method of 6-bromopyridine-3-carboxaldehyde

A technology of bromopyridine and bromomethylpyridine is applied in the field of preparation of 6-bromopyridine-3-carbaldehyde, and can solve the problems of low conversion rate, unsuitability for industrial application, incomplete reaction and the like

Inactive Publication Date: 2017-08-18
SHANGHAI CHEMSPEC CORP
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  • Abstract
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Problems solved by technology

There is also 2-amino-5-picoline as raw material, 2-bromo-5-picoline is prepared by diazotization, and then brominated and hydrolyzed by N-bromosuccinimide to prepare 2-bromo-5 -Pyridinecarbaldehyde (Chemical Reagent, 28(7), 433-434; 2006), this method is due to incomplete reaction, bromination, hydrolysis step yield is only 40%, conversion rate is too low and is not suitable for industrial applications

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  • Preparation method of 6-bromopyridine-3-carboxaldehyde
  • Preparation method of 6-bromopyridine-3-carboxaldehyde
  • Preparation method of 6-bromopyridine-3-carboxaldehyde

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[0044] The present invention provides a preparation method of 6-bromopyridine-3-carbaldehyde, the structural formula of the 6-bromopyridine-3-carbaldehyde is shown in formula III:

[0045]

[0046] The preparation method comprises the steps of: carrying out a bromination reaction of 2-chloro-5-chloromethylpyridine (compound of formula I) in the presence of a brominating reagent to prepare 2-bromo-5-bromomethylpyridine ( Formula II compound), the structural formula of shown formula I compound and formula II compound is as follows:

[0047]

[0048] In the preparation method provided by the present invention, the bromination reagent can be various commonly used bromination reagents in the art, such as hydrogen bromide, bromine, dibromohydantoin, sodium bromide, phosphorus oxybromide, One or more combinations of N-bromosuccinimide, etc. In some preferred embodiments of the present invention, the bromination reagent may preferably be one or more combinations of hydrogen bro...

Embodiment 1

[0066] Take 100g of raw material 2-chloro-5-chloromethylpyridine, put it into Hastelloy autoclave, and add 800g of 25% hydrobromic acetic acid solution. Close the reaction kettle, stir and heat up to 100-110°C. React for 10 hours. The filtrate was removed by filtration and dried to obtain a crude product with a mass of 139.7 g and a content of 92%.

[0067]Dissolve 7.5g of sodium ethylate in 40g of ethanol, under nitrogen protection, and heat up to 50-60°C. 10 g of 2-nitropropane was added dropwise. After the dropwise addition, keep warm at 60°C for 1h. Take 20 g of the above-mentioned 2-bromo-5-bromomethylpyridine, dissolve it in 60 g of ethanol, add it dropwise into the system at 65°C, and keep it warm until the reaction is completed. After the reaction, the salt was removed by filtration. Ethanol was recovered by distillation, and 30 g of DCM was added to the residue, and the pH was adjusted to 6-7 with 1% hydrobromic acid, and the mixture was separated and washed. Th...

Embodiment 2

[0069] Take 100g of raw material 2-chloro-5-chloromethylpyridine, put it into a Hastelloy autoclave, and add 800g of 25% hydrobromic formic acid solution. Close the reaction kettle and raise the temperature to 100-110°C. React for 10 hours. The filtrate was removed by filtration and dried to obtain a crude product with a mass of 142.5 g and a content of 88%.

[0070] Take 11g of sodium tert-butoxide, dissolve it in 40g of solvent tert-butanol, protect it with nitrogen, and raise the temperature to 50-60°C. 10 g of 2-nitropropane was added dropwise. After the dropwise addition, keep warm at 65°C for 1h. Take 20 g of the above-mentioned 2-bromo-5-bromomethylpyridine, dissolve it in 60 g of tert-butanol, add it dropwise into the system at 65°C, and keep it warm until the reaction is completed. After the reaction was completed, the salt was removed by filtration. Recover tert-butanol, add 30 g of DCM to the residue, use 1% hydrobromic acid to pH=6-7, and separate and wash. T...

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Abstract

The invention relates to the field of fine chemical engineering, in particular to a preparation method of 6-bromopyridine-3-carboxaldehyde. The preparation method of 6-bromopyridine-3-carboxaldehyde comprises steps as follows: 2-chloro-5-chloromethylpyridine is subjected to a bromination reaction in the presence of a bromination reagent, and 2-bromo-5-bromomethylpyridine is prepared; 2-bromo-5-bromomethylpyridine is subjected to an oxidation reaction in 2-nitropropane in the presence of alkali, and 6-bromopyridine-3-carboxaldehyde is prepared. According to the provided preparation method, 2-chloro-5-chloromethylpyridine is taken as a raw material, and 6-bromopyridine-3-carboxaldehyde is prepared through the reaction including two steps: bromination and oxidation, a process is simple to operate, the reaction conditions are mild and safe, the cost of raw materials is low, the reaction conversion rate is high, the yield is high, the product is easy to extract, and the method is more suitable for industrial safety production and has higher implementation value and social and economic benefits.

Description

technical field [0001] The invention relates to the field of fine chemicals, in particular to a preparation method of 6-bromopyridine-3-carbaldehyde. Background technique [0002] 6-Bromopyridine-3-carbaldehyde is an important chemical intermediate and has wide application value in the fields of pharmaceuticals and electronic materials. [0003] It is reported in the literature that most of the synthesis methods of 6-bromopyridine-3-carbaldehyde use 2,5-dibromopyridine as raw material, and carry out butyllithium reaction under ultra-low temperature conditions, but the temperature is not easy to control, the reaction conditions are harsh and there are safety hazards, and the raw materials The cost is high, the industrial operation is difficult, and the process will generate more isomer 2-formyl-5-bromopyridine at the same time, which is difficult to separate and remove. (Journal of Natural Science of Xiangtan University 31(1), 53-28; 2009). There is also 2-amino-5-picoline ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 何立汪奇辉许智赵子强
Owner SHANGHAI CHEMSPEC CORP
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