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Method for synthesizing 5-Bromo-2, 4-dichloropyridine

A technology of bromopyridine and chlorpyridine, which is applied in the field of synthesis of pharmaceutical intermediates, can solve the problems of difficult industrialization, low reaction yield, serious pollution, etc., and achieve the effect of easy purification, high reaction yield and simple operation

Inactive Publication Date: 2013-12-04
天津安锦科技发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] This method is seriously polluted, and the reaction yield is very low, and there is a risk of explosion when it encounters water in operation, so it is difficult to realize industrialization

Method used

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  • Method for synthesizing 5-Bromo-2, 4-dichloropyridine
  • Method for synthesizing 5-Bromo-2, 4-dichloropyridine
  • Method for synthesizing 5-Bromo-2, 4-dichloropyridine

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Experimental program
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Effect test

Embodiment 1

[0023] Embodiment 1: laboratory synthesis

[0024] 1. Bromination reaction

[0025] Dissolve 2-amino-4-chloropyridine (50g) in dichloromethane (500mL), cool down to 0°C, slowly add N-bromosuccinimide (76.5g) in batches, stir well after adding , reacted for 30 minutes, and TLC detected that the reaction was complete. Spin the solvent of the reaction solution to dryness first, dissolve the crude product in ethyl acetate, wash with 1mol / L hydrochloric acid, adjust the base and extract with ethyl acetate, combine the organic phases, wash with salt water, dry over sodium sulfate, and concentrate to obtain Product 2 (70g), yield 87%.

[0026] 2. Diazotization reaction

[0027] Dissolve compound 2 (10g) in concentrated hydrochloric acid (200mL) at -30°C, stir evenly, and slowly add sodium nitrite (8.3g) in batches at -30°C under temperature control. Raise the temperature, complete the addition, react at -30°C for 1 hour, add cuprous chloride, raise to room temperature, TLC detect...

Embodiment 2

[0028] Embodiment 2: small test

[0029] 1. Bromination reaction

[0030] Dissolve 2-amino-4-chloropyridine (500g) in dichloromethane (5L), cool down to 0°C, slowly add N-bromosuccinimide (765g) in batches, stir evenly after adding, and react After 30 minutes, TLC detected that the reaction was complete. Spin the solvent of the reaction solution to dryness first, dissolve the crude product in ethyl acetate, wash with 1mol / L hydrochloric acid, adjust the base and extract with ethyl acetate, combine the organic phases, wash with salt water, dry over sodium sulfate, and concentrate to obtain Product 2 (700g), yield 87%.

[0031] 2. Diazotization reaction

[0032] Dissolve compound 2 (100g) in concentrated hydrochloric acid (2L) at -30°C, stir evenly, control the temperature at -30°C and slowly add sodium nitrite (83g) in batches, there will be bubbles during the addition process, and the temperature will rise , after the addition is complete, react at -30°C for 1 hour, add cu...

Embodiment 3

[0033] Embodiment 3: pilot test

[0034] 1. Bromination reaction

[0035] Dissolve 2-amino-4-chloropyridine (5kg) in dichloromethane (50L), cool down to 0°C, slowly add N-bromosuccinimide (7.65kg) in batches, stir well after adding, The reaction was carried out for 30 minutes, and TLC detected that the reaction was complete. Spin the solvent of the reaction solution to dryness first, dissolve the crude product in ethyl acetate, wash with 1mol / L hydrochloric acid, adjust the base and extract with ethyl acetate, combine the organic phases, wash with salt water, dry over sodium sulfate, and concentrate to obtain Product 2 (7kg), the yield was 87%.

[0036] 2. Diazotization reaction

[0037] Dissolve compound 2 (1kg) in concentrated hydrochloric acid (20L) at -30°C, stir evenly, control the temperature at -30°C and slowly add sodium nitrite (830g) in batches, there will be bubbles during the addition process, and the temperature will rise , after the addition is complete, reac...

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Abstract

The invention relates to a method for synthesizing 5-Bromo-2, 4-dichloropyridine. According to the method, 2-amino-4-thloropyridine is used as a starting raw material, a key intermediate is obtained through the bromination reaction, wherein the yield is greater than 80%, then, the 5-Bromo-2, 4-dichloropyridine is obtained through diazotization and chlorination, wherein the total yield is greater than 50%. According to the method, various negative factors in the amplified production of the 5-Bromo-2, 4-dichloropyridine can be overcome. The method has the advantages of being low in raw material price, free of use of dangerous reagents, high in yield, capable of enabling purification to be conveniently conducted and the like, and therefore the product can be generated on a large scale, and is low in price and convenient to popularize.

Description

technical field [0001] The invention relates to the field of biomedicine, in particular to a method for synthesizing a drug intermediate. Background technique [0002] 2,4-Dichloro-5-bromopyridine is an important biopharmaceutical intermediate, which can be widely used in the synthesis of various drugs. It has a small molecular weight and a unique structure, and can be derived from a variety of downstream products and has a wide range of uses. At present, there are several methods for synthesizing 2,4-dichloro-5-bromopyridine as follows, but these methods involve the use of dangerous goods, expensive raw materials, low reaction yield, generally not more than 10%, and inconvenient to scale up Shortcomings such as making 2,4-dichloro-5-bromopyridine manufacturers are very few, and the price is expensive, which seriously hinders the development of its downstream products and its further development in the field of biomedicine. [0003] At present, there are several methods fo...

Claims

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Application Information

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IPC IPC(8): C07D213/61
Inventor 邱燕辉郭少雄杨廷全杨芳宋艳民
Owner 天津安锦科技发展有限公司
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