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A kind of synthetic method of 2-amino-3-bromo-5-chloropyridine

A synthesis method and chloropyridine technology, applied in the direction of organic chemistry and the like, can solve the problems of high price, many by-products, low product yield and the like, and achieve the effects of easy control of the reaction, moderate reaction conditions and high product purity.

Active Publication Date: 2016-04-20
陕西友帮生物医药科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] (1) There are many by-products, resulting in a darker color of the product, which is difficult to refine and purify
Although it can be recrystallized multiple times with organic solvents, the quality still cannot meet the high requirements, and repeated crystallization leads to low product yield, increased cost, and cumbersome operation;
[0005] (2) The chemical reduction method used is very serious to the corrosion of equipment and the pollution of the environment, and its development has been restricted at present;
[0006] (3) The source of raw materials is limited, the price is expensive, and the operation is troublesome;
[0007] (4) Need to use noble metal catalyst, increased preparation cost

Method used

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  • A kind of synthetic method of 2-amino-3-bromo-5-chloropyridine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019]

[0020] Add 14.5ml of absolute ethanol solvent into a 50ml round-bottom single-necked flask, insert a thermometer, start a magnetic stirrer, and add 2.56g of 2-amino-5-chloropyridine, add N-bromosuccinimide 1.6 g, reacted under stirring at 20°C for 6.5 hours. TLC and GC confirmed the completion of the reaction. The solvent was removed by rotary evaporation to obtain a crude product, which was separated by silica gel column chromatography to obtain the pure product 2-amino-3-bromo-5-chloropyridine. After drying, the calculated yield was 65.1%, and the purity was 99.50% (GC). NMR analysis: 1HMR (CDCl3) 400MHz: δ7.98 (s, 1H); δ7.66 (s, 1H); δ4.96 (bs, 2H). Melting point 83°C-85°C (literature 82°C-83°C).

Embodiment 2

[0022] In a 1L round-bottom single-necked flask, add 420ml of a mixed solvent with a volume ratio of DMF and ethanol of 1:1.1, insert a thermometer and start a magnetic stirrer, and add 110.3g of 2-amino-5-chloropyridine, N-bromo 229.4 g of diimides were reacted at 5°C for 9 hours while stirring. TLC and GC confirmed the completion of the reaction. The solvent was removed by rotary evaporation to obtain a crude product, which was recrystallized from dichloromethane to obtain the pure product 2-amino-3-bromo-5-chloropyridine. After drying, the calculated yield was 56.3%, and the purity was 97.40% (GC). Melting point 82°C-84°C (literature 82°C-83°C).

Embodiment 3

[0024] In a 10L round bottom three-neck flask, add 4500ml of mixed solvent with a volume ratio of DMF and ethanol of 1:1.5, insert a thermometer and install a condensation reflux device, start a magnetic stirrer, and add 1580.6g of 2-amino-5-chloro Pyridine, N-bromosuccinimide 5673.1g, stirred and reacted at 55°C for 5.5 hours. TLC and GC confirmed the completion of the reaction. The solvent was removed by rotary evaporation to obtain a crude product, which was recrystallized from ethyl acetate to obtain the pure product 2-amino-3-bromo-5-chloropyridine. After drying, the calculated yield was 64.3%, and the purity was 97.20% (GC). Melting point 82°C-84°C (literature 82°C-83°C).

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Abstract

The invention belongs to the field of organic synthesis and in particular relates to a synthetic method of 2-amino-3-bromo-5-chloropyridine. The synthetic method comprises the following steps: reacting raw materials 2-amino-5-chloropyridine and N-bromosuccinimide with a molar weight of 1: (0.4-4) in a proper solvent for 0.5-24 hours at 1-100 DEG C to generate a 2-amino-3-bromo-5-chloropyridine crude product, and purifying to obtain the pure product 2-amino-3-bromo-5-chloropyridine. The synthetic method has the beneficial effects that the reaction raw materials are available and are reasonable in prices; meanwhile, heavy metals and corrosive gases are not used in the preparation reaction; the reaction is mild; the synthetic method does not have special requirements for reaction equipment and common corrosion resistant equipment can be used for production; besides, with the advantageous conditions such as moderate reaction conditions, easily controlled reaction and high product purity, the process is easy to popularize.

Description

(1) Technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a synthesis method of 2-amino-3-bromo-5-chloropyridine. (2) Background technology [0002] 2-amino-3,5-dichloropyridine 2-amino-3,5-dichloropyridine is an important intermediate in organic synthesis, mainly used in pharmaceutical intermediates, organic synthesis, organic solvents, and can also be used in dye production and pesticide production and spices etc. [0003] The preparation of existing 2-amino-3-bromo-5-chloropyridine has the following disadvantages: [0004] (1) There are many by-products, resulting in a darker color of the product, which is difficult to refine and purify. Although organic solvents can be used to recrystallize multiple times, the quality still cannot meet the high requirements, and repeated crystallization leads to low product yield, increased cost, and cumbersome operation; [0005] (2) The chemical reduction method used is very ser...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/73
CPCC07D213/73
Inventor 付锐曹惊涛来新胜
Owner 陕西友帮生物医药科技有限公司