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

A technology of fluorobenzoic acid and cyano group, applied in the field of preparation 2, can solve the problems of potential safety hazard, low Sandmeier reaction yield, etc., and achieve the effects of low product cost, short steps, and simple operation process

Active Publication Date: 2014-08-06
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] 38g (0.2mol) of 2,6-dichloro-3-fluorobenzonitrile and 42.72g (0.24mol) of N-bromosuccinimide were added to 100mL of concentrated sulfuric acid, the reaction was stirred at room temperature for 30h, and the reaction solution was slowly poured into In 200 mL of ice-water mixture, white solid was precipitated, suction filtered, the filter cake was washed with water, and dried to obtain 52.8 g of white solid product, which was 2,6-dichloro-3-cyano-5-fluorobromobenzene, and the yield was 98%. . m.p.122-124℃; 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=254 Hz); EI-MS (m / z): 269 (M + ).

Embodiment 2

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

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

Embodiment 3

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

[0027] 38g (0.2mol) of 2,6-dichloro-3-fluorobenzonitrile and 34.2g (0.12mol) of bromobarbituric acid were added to 100mL of concentrated sulfuric acid, the reaction was stirred at 50°C at room temperature for 5h, and the reaction solution was slowly poured into 200mL In the ice-water mixture, a white solid was precipitated, suction filtered, the filter cake was washed with water, and dried to obtain 50.6 g of a white solid product. 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 invention relates to a preparation method of 2,4-dichloro-3-cyano-5-fluorobenzoic acid, in particular to a preparation method of 2,4- Method for Dichloro-3-cyano-5-fluorobenzoic acid. (2) Background technology [0002] 2,4-Dichloro-3-cyano-5-fluorobenzoic acid is a key intermediate in the preparation of a novel fluoroquinolone drug finafloxacin hydrochloride (BAY35-3377), which is currently in clinical phase III and has good market prospects. 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 reported 5-fluoro-1,3-xylene Under the catalysis of Lewis acid, it reacts with chlorine to obtain 2,4-dichloro-5-fluoro-1,3-xylene, and then reacts with chlorine through free radicals to obtain 2,4-dichloro-5-fluoro-3-dichloro Methyl-1-trichloromethylbenzene, then hydrolyzed to obtain 2,4-dichloro-5-fluoro-3-formyl-benzoic acid, and continued to reac...

Claims

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Application Information

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Patent Type & Authority Patents(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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