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Preparation method of amino pyridine bromide compound

A technology for aminobromopyridine and bromopyridinecarboxamide, which is applied in the field of preparing aminobromopyridine based on Hoffman degradation reaction, can solve the problems of unobtainable raw materials, harsh reaction conditions, long process route, etc., and meets equipment requirements Low, high product purity, simple process effect

Inactive Publication Date: 2010-05-12
JIANGSU POLYTECHNIC UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0025] The object of the present invention is to provide a method for preparing aminobromopyridine with mild reaction conditions and simple process; it is a method for preparing 2-aminobromopyridine based on the Hofmann degradation reaction, so as to overcome the above-mentioned reaction raw materials for preparing bromoaminopyridine Not easy to obtain, harsh reaction conditions, long process route defects, easy to industrialized production

Method used

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  • Preparation method of amino pyridine bromide compound
  • Preparation method of amino pyridine bromide compound
  • Preparation method of amino pyridine bromide compound

Examples

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Embodiment 1

[0035] Add 24g (0.6mol) of sodium hydroxide and 180g (10mol) of water into a four-neck flask equipped with a stirrer, a condenser, and a thermometer, and slowly add 17.6g (0.11mol) of liquid bromine at -5 to 0°C, dropwise After finishing this temperature, the reaction was continued for 1.0 h to obtain fresh sodium hypobromite solution. Add 20.1g (0.1mol) of 6-bromo-2-pyridinecarboxamide in batches to the sodium hypobromite solution until completely dissolved, react at 70°C for 0.5h, cool down to 0°C after the reaction, filter to obtain a white solid Crude. The filtrate was extracted with dichloromethane, the solvent was recovered, cooled and filtered to obtain a white solid crude product. The crude product was recrystallized from petroleum ether and dried to obtain 9.2 g of 2-amino-6-bromopyridine with a yield of 53.2% and a melting point of 88-89°C. The purity was 99.0% by HPLC.

Embodiment 2

[0037] With the technological operation step of embodiment 1, different conditions are:

[0038] 20g (0.5mol) of sodium hydroxide, 216g (12mol) of water, 19.2g (0.12mol) of liquid bromine, 20.1g (0.1mol) of 6-bromo-2-pyridinecarboxamide, the degradation reaction was 60°C for 1.0h, and 2 -Amino-6-bromopyridine 9.4g, yield 54.3%, melting point 88-89°C.

Embodiment 3

[0040] With the technological operation step of embodiment 1, different conditions are:

[0041]20g (0.5mol) of sodium hydroxide, 216g (12mol) of distilled water, 20.1g (0.1mol) of 5-bromo-2-pyridinecarboxamide, degraded at 60°C for 1.0h, and extracted the filtrate with chloroform to obtain a light yellow solid 2-amino -5-bromopyridine 10.6g, yield 61.3%, melting point 135-138°C.

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Abstract

The invention discloses a preparation method of an amino pyridine bromide compound, relating to the field of organic synthesis. The amino pyridine bromide compound takes pyridine bromide formamide as raw material, and is prepared according to the following formula of Hofmann degradation reaction which comprising the following steps of: (1) dropping liquid bromine into alkali liquid with the concentration of 2.0-4.0 mol / L at -5-0 DEG C, reacting for 1.0 hour to obtain sodium hypobromite or potassium hypobromite, wherein the alkali is sodium hydroxide, potassium hydroxide or sodium methoxide; (2) adding the pyridine bromide formamide with the general foumula I to the hypobromite solution at room temperature for dissolving, raising temperature to 50-80 DEG C, reacting for 0.5-2 hours, decreasing temperature to 0 DEG C for separating out solids, and filtrating to obtain crude products; extracting the filtrate with an organic solvent, removing the solvent, and merging the crude products; re-crystallizing by using petroleum ether, and drying to obtain amino pyridine bromide. Wherein, the mole ratio of the general formula I to the alkali is 1:4-8, the mole ratio of the general formula I to water is 1:80-160, and the mole ratio of the general formula I to the liquid bromine is 1:1-2; and the organic solvent is dichloromethane, chloroform or normal hexane. The invention has the advantages of one-step reaction, simple process, low requirement on equipment, and high product purity, and the yield coefficient is around 50 percent.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a method for preparing aminobromopyridine based on a Hofmann degradation reaction (Hofmanndegradation reaction). Background technique [0002] In recent years, people have done a lot of work on the application of bromoaminopyridine. Since the bromine atom / amino group can be replaced by other groups, heterocycles can be introduced into many compounds. Aminopyridine bromide is an important intermediate, which is widely used in organic synthesis, medicine, pesticide and other fields. [0003] In WO2005060963, 2-amino-6-bromopyridine is used as raw material to synthesize 11-β-hydroxysteroid dehydrogenase inhibitors and related compounds, which can be used to treat diabetes and obesity; in WO2006036816, 2-amino-6-bromopyridine is used as raw material The synthetic cell protectant aminotetrahydroquinoline can prevent HIV infection; in WO2006038116, 2-amino-4-bromopyridine is used as a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/73
Inventor 方永勤孙德鑫许亮殷丽丽张丽琼
Owner JIANGSU POLYTECHNIC UNIVERSITY
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