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Preparation method of 2,6-difluorobenzyl bromide

A technology of difluorobromobenzyl and difluorotoluene, applied in the field of bromination reaction to prepare 2,6-difluorobromobenzyl, which can solve the problem of introducing impurities from azobisisobutyronitrile and the price of N-bromosuccinimide Expensive and other issues, to achieve high product purity, reduce production costs, and high yield

Inactive Publication Date: 2011-05-25
CHANGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The present invention overcomes the problems of expensive N-bromosuccinimide and impurities introduced by azobisisobutyronitrile in the above method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] In a 150ml four-necked flask equipped with a stirring, thermometer and reflux condensing device, add 1.28g (0.01mol) of 2,6-difluorotoluene, 3.03g (0.015mol) of hydrobromic acid with a mass fraction of 40%, and 30ml of difluorotoluene Chloromethane was heated to reflux under the irradiation of a 1000W iodine-tungsten lamp. Slowly add 2.27g (0.02mol) of hydrogen peroxide with a mass fraction of 30%, and the rate of addition should be such that the red color fades. After reacting for 10 h, GC detected that the reaction of raw materials was complete, and the solution was light yellow. After cooling, the reaction solution was washed with 20 ml of saturated sodium sulfite solution, washed with water, the organic layer was dried with anhydrous sodium sulfate, filtered, and the solvent was evaporated from the filtrate under reduced pressure. Silica gel column chromatography (eluent: petroleum ether (60-90°C)) yielded 1.88g of 2,6-difluorobenzyl bromide with a purity of 99.3% ...

Embodiment 2

[0023] With the technological operation step of embodiment 1, different conditions are:

[0024] 2.03g (0.01mol) hydrobromic acid with a mass fraction of 40%, 1.13g (0.01mol) hydrogen peroxide with a mass fraction of 30%, 30ml chloroform, and react for 6h. 1.80 g of 2,6-difluorobenzyl bromide was obtained with a purity of 99.5% and a yield of 86.6%.

Embodiment 3

[0026] With the technological operation step of embodiment 1, different conditions are:

[0027] 3.03g (0.015mol) of hydrobromic acid with a mass fraction of 40%, 2.27g (0.02mol) of hydrogen peroxide with a mass fraction of 30%, and 30ml of ethyl acetate were reacted for 18 hours. 1.67g of 2,6-difluorobenzyl bromide was obtained with a purity of 99.2% and a yield of 80.2%.

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Abstract

The invention relates to the field of organic synthesis, in particular to a preparation method of 2,6-difluorobenzyl bromide. The method comprises the following steps: (1) in the presence of an organic or inorganic solvent, adding a compound 2,6-difluorotoluene and hydrobromic acid the mass fraction of which is 40%, and dropwise adding oxydol the mass fraction of which is 30% under lighting conditions to react for 6-24 hours, wherein on the basis of the compound 2,6-difluorotoluene, the mol ratio of the compound 2,6-difluorotoluene to HBr is 1:(1-3.5), and the mol ratio of the compound 2,6-difluorotoluene to H2O2 is 1:(1-3.5); and (2) respectively washing the reaction liquid with a saturated sodium sulfite solution and water, drying with anhydrous sodium sulfate, evaporating under reduced pressure to remove the solvent, and carrying out silica gel column chromatography to obtain the compound 2,6-difluorobenzyl bromide. The invention uses hydrobromic acid and oxydol instead of the traditional brominating reagent N-bromosuccinimide, thereby lowering the production cost; the invention uses lighting instead of the initiator azodiisobutyronitrile, thus the invention has the advantages of mild reaction conditions, high product purity (>=99.0%) and the like; and the invention also has the advantage of high yield.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a method for preparing 2,6-difluorobenzyl bromide through bromination reaction. The invention provides a simple and economical method for preparing 2,6-difluorobenzyl bromide. Background technique [0002] 2,6-Difluorobenzyl bromide is an important pharmaceutical intermediate, Ju Wenjian et al. ) rufinamide synthesized from 2,6-difluorobenzyl bromide, the chemical name is 1-[(2,6-difluorophenyl)methyl]-1H-1,2,3-tri Azole-4-carboxamide is a sodium ion channel antagonist developed by Novartis Pharmaceuticals of Switzerland. It was listed in the European Union for the first time in 2007. Its trade name is Inovelon. It is used for auxiliary treatment of partial epileptic seizures and Lennox-Gastaut syndrome; : Qin Bingjie, Zhou Ting, Lu Hong, Jiang Shibo, Xie Lan. Acta Pharmaceutica Sinica, 2009, 44(11): 1233-1243) The new drug TMC125 synthesized from 2,6-difluorobenzyl bromide is ...

Claims

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Application Information

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IPC IPC(8): C07C25/13C07C17/14
Inventor 方永勤李江河王兆岗
Owner CHANGZHOU UNIV
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