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Synthesis method of 3-chloro-2,4-difluorobenzoic acid

A technology of difluorobenzoic acid and a synthesis method, which is applied in the field of synthesis of 3-chloro-2,4-difluorobenzoic acid, can solve the problems of unfavorable industrial production, harsh reaction conditions, large pollution in the reaction process, etc. The effect of industrialized production, mild reaction conditions and low pressure of the three wastes

Inactive Publication Date: 2017-01-04
CHANGZHOU VOCATIONAL INST OF ENG
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] The technical problem to be solved by the present invention is: aiming at the problems of harsh reaction conditions, heavy pollution in the reaction process and unfavorable industrialized production in the synthesis method of 3-chloro-2,4-difluorobenzoic acid in the prior art, provide A kind of synthetic reaction condition is mild, easy to operate and control, three wastes pressure is relatively low, the synthetic method of the 3-chloro-2,4-difluorobenzoic acid that is conducive to industrial production

Method used

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  • Synthesis method of 3-chloro-2,4-difluorobenzoic acid

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Effect test

Embodiment 1

[0024] A kind of synthetic method of 3-chloro-2,4-difluorobenzoic acid, the method comprises the steps:

[0025] (1) Pour 300mL of sulfuric acid into a dry 500mL four-necked bottle, add 54.5g of 1,2,3-trichlorobenzene in batches under stirring, cool down to 0-10°C after it is completely dissolved, and then add in batches 55.0gNBS, keep at this temperature for 0.5h after adding. GC tracking detection, when the content of 1,2,3-trichlorobenzene is less than or equal to 2%, the bromination reaction is ended;

[0026] (2) Pour the mixture prepared in step (1) into 1000mL of ice-water mixture, separate the oil layer, wash the oil layer twice with 200mL of cold water respectively, separate out a light yellow granular solid, filter it with suction, and weigh it after drying. Quantity, get 70.7g of 1-bromo-2,3,4-trichlorobenzene, the content is 98.021% (GC), the molar yield is 90.5% (based on 1,2,3-trichlorobenzene), melting range 58.2~60.7℃;

[0027] (3) Pour 300mL of DMF into a d...

Embodiment 2

[0034] A kind of synthetic method of 3-chloro-2,4-difluorobenzoic acid, the method comprises the steps:

[0035] (1) Pour 220mL of sulfuric acid into a dry 500mL four-neck bottle, add 54.5g of 1,2,3-trichlorobenzene in batches under stirring, cool down to 0-20°C and add in batches after it is completely dissolved 58.0g NBS, keep at this temperature for 0.5 hours after adding. GC tracking detection, when the content of 1,2,3-trichlorobenzene is less than or equal to 2%, the bromination reaction is ended;

[0036] (2) Pour the mixture prepared in step (1) into 1000mL ice-water mixture, separate the oil layer, wash the oil layer twice with 300mL cold water respectively, separate out light yellow granular solid, suction filter, dry and weigh Quantity, get 72.5g of 1-bromo-2,3,4-trichlorobenzene, the content is 95.893% (GC), the molar yield is 92.8% (based on 1,2,3-trichlorobenzene), melting range 53.8~68.3℃;

[0037] (3) Pour 400mL of DMF into a dry 500mL four-neck bottle, drop...

Embodiment 3

[0044] (1) Pour 300mL of sulfuric acid into a dry 500mL four-neck bottle, add 54.5g of 1,2,3-trichlorobenzene in batches under stirring, and add 60.0 g of After adding gNBS, keep it warm at this temperature and track and detect it by GC. When the content of 1,2,3-trichlorobenzene is ≤2%, the bromination reaction is ended;

[0045] (2) Pour the mixture prepared in step (1) into 1500mL ice-water mixture, separate the oil layer, wash the oil layer 3 times with 300mL cold water respectively, separate out light yellow granular solid, suction filter, dry and weigh Quantity, get 73.1g of 1-bromo-2,3,4-trichlorobenzene, the content is 95.739% (GC), the molar yield is 93.5% (based on 1,2,3-trichlorobenzene), melting range 56.8~59.6℃;

[0046] (3) Pour 320mL of DMF into a dry 500mL four-neck bottle, drop 30.0g of cuprous cyanide under stirring, and then add the 1-bromo-2,3,4- Trichlorobenzene, heat preservation reaction at 100-170 ° C and GC detection, when the content of 1-bromo-2,3,...

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Abstract

The invention relates to a synthesis method of 3-chloro-2,4-difluorobenzoic acid. The method comprises: taking 1,2,3-trichlorobenzene and N-bromosuccinimide to react, taking CuCN and 1-bromo-2,3,4-trichlorobenzene to react, taking the 1-bromo-2,3,4-trichlorobenzene and KF to react and taking 3-chloro-2,4-difluorobenzonitrile and sulfuric acid to react, so as to form the 3-chloro-2,4-difluorobenzoic acid. According to the synthesis method, synthesis reaction conditions are that a reaction is carried out at normal pressure and reaction temperature fluctuates between 0 and 250 DEG C; the obtained finished product is a light yellow powdery solid and the content is more than or equal to 99.0 percent; the total mol yield of the 3-chloro-2,4-difluorobenzoic acid can reach 61.5 percent; whole reaction conditions are moderate and the method is convenient to operate and control; pressure of waste gas, waste water and waste residues is relatively low so that industrial production is facilitated.

Description

technical field [0001] The invention relates to a method for synthesizing a drug intermediate that can be used as quinolones and a drug intermediate that can be used as a pyrazole antibacterial agent, in particular a method for synthesizing 3-chloro-2,4-difluorobenzoic acid. Background technique [0002] The English name of 3-chloro-2,4-difluorobenzoic acid is 3-chloro-2,4-difluorobenzoic acid, and the molecular formula is C 7 h 3 CIF 2 o 2 , is a drug intermediate of quinolones and pyrazoles antibacterial agents. For the research of 3-chloro-2,4-difluorobenzoic acid synthetic method in the prior art, mainly contain following five kinds at present: [0003] 1. It is mentioned in the literature (US: 2009111851A1, US: 6348624B1) to use 2,4-difluorobromobenzene as raw material, use n-butyllithium, hexachloro-2-acetone, etc. to obtain 3 -Chloro-2,4-difluorobenzoic acid, but there is a lack of specific data such as yield in this document; [0004] 2. It is mentioned in the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/08C07C63/70
CPCC07C51/08C07C17/12C07C253/14C07C253/30
Inventor 赵昊昱张启蒙蒋涛
Owner CHANGZHOU VOCATIONAL INST OF ENG
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