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Preparation method of 3,4,5-trifluorobromobenzene

A technology of trifluorobromobenzene and trifluoroaniline, which is applied in the preparation of pharmaceutical intermediates and the field of pesticides, can solve the problems of potential safety hazards, low reduction yield, and many impurities, and achieve the effect of reducing usage and solving high production costs

Active Publication Date: 2016-03-30
ZHEJIANG YONGTAI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Christophe Heiss et al. disclose a preparation method of 3,4,5-trifluorobromobenzene (European Journal of Organic Chemistry, (3), 447-451; 2003), which uses 1,2,3-trifluorobenzene as a starting material , first carry out lithium metallization to obtain the corresponding aryllithium compound, and then obtain the corresponding brominated polyfluorobenzene through bromination reaction. reaction, more impurities in the product
[0005] In China, CN201310580913.0 discloses that 2,3,4-trifluoroaniline is deaminated by brominated diazonium to obtain 3,4,5-trifluorobromobenzene. This reaction uses one equivalent of bromine to prepare the brominated 2 , 3,4-trifluoro-6-bromoaniline is separated, and the 2,3,4-trifluoro-6-bromoaniline diazo is prepared and then reduced. This diazo solution is extremely unstable, not only down The reduction yield is low, and there is a great potential safety hazard
In addition, the use of one equivalent of bromine leads to higher production costs, and since bromine is difficult to separate from the waste liquid, it is difficult to recycle, resulting in environmental pollution

Method used

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  • Preparation method of 3,4,5-trifluorobromobenzene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Embodiment 1: the preparation of 3,4,5-trifluorobromobenzene

[0024] Put 500 milliliters of water in the reactor, 147 grams (1 mole) of 2,3,4-trifluoroaniline, 214.5 grams (mass concentration is 98%, 3.5 moles) of glacial acetic acid, control the temperature in the reactor at 25~30 ℃ 450 grams of sulfuric acid (mass concentration: 98%, 4.5 moles) was added dropwise, and after the addition was completed, the temperature in the reactor was controlled to react at 25-30° C. for 1 hour.

[0025] Control the temperature in the reactor to be 35-40°C and add 79.9 grams (0.5 moles) of bromine dropwise for about 4 hours, then control the temperature in the reactor to be 35-40°C and add hydrogen peroxide and water for dilution , The dropping time is controlled within 2-2.5 hours, and the reaction is kept warm after the dropping is completed. During the heat preservation reaction process, the product mixture obtained by the heat preservation reaction is sampled, the sample is neu...

Embodiment 2

[0030] Embodiment 2: the preparation of 3,4,5-trifluorobromobenzene

[0031] Example 1 was repeated except that no water for dilution was added when hydrogen peroxide was added dropwise to obtain 181.9 g of product 3,4,5-trifluorobromobenzene with a purity of 97.1% and a yield of 83.7%.

[0032] The inventor found unexpectedly that in the process of preparing 2,3,4-trifluoroaniline sulfate by reacting 2,3,4-trifluoroaniline, adding water for dilution while adding hydrogen peroxide dropwise, the product 3 , the yield of 4,5-trifluorobromobenzene has a certain influence.

Embodiment 3

[0033] Embodiment 3: the preparation of 3,4,5-trifluorobromobenzene

[0034] Repeat Example 1, the difference is that the operation of "dropping bromine 79.9 grams (0.5 moles)" is replaced by "dropping bromine 95.8 grams (0.6 moles)" to obtain the product 3,4,5-trifluorobromobenzene 205.6 grams, the purity is 97.2%, and the yield is 94.7%.

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Abstract

The present invention relates to a preparation method of 3,4,5-trifluorobromobenzene. The preparation method is simple in process, low in cost, mild in condition, friendly to environment, and high in process safety, and can effectively reduce the usage amount of bromine, as well as increase the product yield.

Description

technical field [0001] The invention relates to the field of preparation of pesticides and pharmaceutical intermediates, in particular to a preparation method of 3,4,5-trifluorobromobenzene compound. Background technique [0002] The molecular formula of 3,4,5-trifluorobromobenzene is C 6 h 2 BrF 3 , the molecular weight is 210.98, and the CAS registration number is 138526-69-9. 3,4,5-trifluorobromobenzene undergoes Grignard reaction to realize various functionalization, and further synthesizes various polyfluorine-substituted compounds, so it is widely used in liquid crystal materials , pharmaceutical and pesticide intermediates, etc. [0003] wo2013041497A1 discloses a method for synthesizing a cathepsin C inhibitor with 3,4,5-trifluorobromobenzene as a raw material. In this method, 3,4,5-trifluorobromobenzene is first converted into boron reagent, and then combined with halogen Aromatic substrates are used for coupling; Dhayalan Vasudevan discloses a method for synthe...

Claims

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Application Information

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IPC IPC(8): C07C25/13C07C17/35
Inventor 周日喜何人宝金逸中
Owner ZHEJIANG YONGTAI TECH CO LTD
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