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Preparation method of 2,4-dichloro-3-cyano-5-fluobenzoic acid

A technology of fluorobenzoic acid and cyano, which is applied in the field of preparation 2, can solve the problems of potential safety hazards and low yield of Sandmeyer reaction, and achieve the effects of low product cost, short steps and high total yield

Active Publication Date: 2012-07-25
ZHEJIANG UNIV OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The nitrification reaction of this method produces a large amount of acidified waste water in one step, and the Sandmeyer reaction yield is not high and requires the equivalent of cuprous cyanide and more than three times the equivalent of highly toxic substance sodium cyanide, which will bring great security risk

Method used

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  • Preparation method of 2,4-dichloro-3-cyano-5-fluobenzoic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0020] Synthesis of 2,6-dichloro-3-cyano-5-fluorobromobenzene

[0021] Add 38g (0.2mol) of 2,6-dichloro-3-fluorobenzonitrile and 42.72g (0.24mol) of N-bromosuccinimide to 100mL of concentrated sulfuric acid, stir at room temperature for 30h, and pour the reaction solution into In 200mL of ice-water mixture, a white solid precipitated out, filtered with suction, washed the filter cake with water, and dried to obtain 52.8g of a white solid product, which was 2,6-dichloro-3-cyano-5-fluorobromobenzene, with a yield of 98% . m.p.122-124°C; 1 H NMR (400MHz, CDCl 3 )δ: 7.69 (d, J=7.6Hz, 1H); 13 C NMR (100MHz, CDCl 3 )δ: 112.1(d, J=3Hz), 116.5, 122.1(d, J=9Hz), 125.1(d, J=20Hz), 125.2(d, J=24Hz), 134.0(d, J=4Hz), 156.0 (d, J=254Hz); EI-MS (m / z): 269 (M + ).

Embodiment 2

[0023] Synthesis of 2,6-dichloro-3-cyano-5-fluorobromobenzene

[0024] Add 38g (0.2mol) of 2,6-dichloro-3-fluorobenzonitrile and 34.44g (0.12mol) of dibromocyanuric acid to 100mL of concentrated sulfuric acid, stir and react at 0°C for 40h, and pour the reaction solution into 200mL In the ice-water mixture, a white solid was precipitated, filtered with suction, washed the filter cake with water, and dried to obtain 52.8 g of a white solid product, 2,6-dichloro-3-cyano-5-fluorobromobenzene, with a yield of 96%, n.p. 122.5-124°C.

Embodiment 3

[0026] Synthesis of 2,6-dichloro-3-cyano-5-fluorobromobenzene

[0027] Add 38g (0.2mol) of 2,6-dichloro-3-fluorobenzonitrile and 34.2g (0.12mol) of bromobarbituric acid to 100mL of concentrated sulfuric acid, stir and react at room temperature at 50°C for 5h, and pour the reaction solution into 200mL In the mixture of ice and water, a white solid precipitated out. Suction filtration, washing the filter cake with water, and drying gave 50.6 g of a white solid product, and the yield of 2,6-dichloro-3-cyano-5-fluorobromobenzene was 94%. n.p.122-124℃

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Abstract

The invention relates to a preparation method of 2,4-dichloro-3-cyano-5-fluobenzoic acid, which comprises the following steps: reacting 2,6-dichloro-3-fluorbenzonitrile, which is used as a raw material, in a solvent concentrated sulfuric acid under the action of a bromization reagent to generate 2,6-dichloro-3-cyano-5-fluorobromobenzene; and preparing an alkane Grignard reagent, carrying out halogen-metal exchange reaction with 2,6-dichloro-3-cyano-5-fluorobromobenzene to prepare a 2,6-dichloro-3-cyano-5-fluorobromobenzene Grignard reagent, reacting with carbon dioxide, and carrying out after-treatment to obtain the target product 2,4-dichloro-3-cyano-5-fluobenzoic acid. Compared with the prior art, the invention has the advantages of simple steps, convenient operating procedure, high total yield, low cost, high safety, environmental protection and the like, is beneficial to industrial large-scale production, and has high implementation value and socioeconomic performance.

Description

(1) Technical field [0001] The present invention relates to a preparation method of 2,4-dichloro-3-cyano-5-fluorobenzoic acid, in particular to a preparation method of 2,4-dichloro-3-fluorobenzonitrile with 2,6-dichloro-3-fluorobenzonitrile Method for dichloro-3-cyano-5-fluorobenzoic acid. (2) Background technology [0002] 2,4-dichloro-3-cyano-5-fluorobenzoic acid is a key intermediate for the preparation of a new fluoroquinolone drug finafloxacin hydrochloride (BAY35-3377), which is currently in phase III clinical trials and has Very good market prospect. Before the present invention provides, there are mainly two kinds of synthetic methods of existing 2,4-dichloro-3-cyano-5-fluorobenzoic acid: (1) US6229040 reports 5-fluoro-1,3-xylene React with chlorine gas under Lewis acid catalysis to get 2,4-dichloro-5-fluoro-1,3-xylene, then react with chlorine gas to get 2,4-dichloro-5-fluoro-3-dichloro Methyl-1-trichloromethylbenzene, then hydrolyzed to obtain 2,4-dichloro-5-flu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C255/57C07C253/30
Inventor 陈志卫苏为科郑利冬袁其亮王超陈寅镐
Owner ZHEJIANG UNIV OF TECH
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