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Preparation method of 2-bromine-3-fluorobenzoic acid

A technology for fluorobenzoic acid and fluorotrifluorotoluene is applied in the field of preparation of 2-bromo-3-fluorobenzoic acid, and achieves the effects of mild process conditions, reasonable process design, and cheap and readily available raw materials

Inactive Publication Date: 2013-01-30
陈卫东
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

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Method used

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  • Preparation method of 2-bromine-3-fluorobenzoic acid
  • Preparation method of 2-bromine-3-fluorobenzoic acid
  • Preparation method of 2-bromine-3-fluorobenzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Example 1, a preparation method of 2-bromo-3-fluorobenzoic acid, which uses m-fluorobenzotrifluoride as a raw material, and finally obtains the target product 2- Bromo-3-fluorobenzoic acid; the procedure is as follows:

[0032] (1) Nitration: Using sulfuric acid as a solvent, m-fluorobenzotrifluoride and nitric acid are used for nitration reaction. The molar ratio of m-fluorobenzotrifluoride to nitric acid is 1.0:1.6, and the reaction temperature is 20°C. The reaction produces 4-fluoro- 2-trifluoromethylnitrobenzene;

[0033] (2) Bromination: use sulfuric acid as solvent and dibromohydantoin as bromination reagent, wherein the molar ratio of 4-fluoro-2-trifluoromethylnitrobenzene to dibromohydantoin is 1.2:1.0, and the reaction temperature It is 20°C; the bromination reaction in this step yields 3-bromo-4-fluoro-2-trifluoromethylnitrobenzene, 5-bromo-4-fluoro-2-trifluoromethyl Brominated mixtures of nitrobenzene;

[0034] (3) Reduction: In the water phase, acetic aci...

Embodiment 2

[0038] Example 2, a preparation method of 2-bromo-3-fluorobenzoic acid, which uses m-fluorobenzotrifluoride as a raw material, and finally obtains the target product 2- Bromo-3-fluorobenzoic acid; the procedure is as follows:

[0039] (1) Nitration: Using sulfuric acid as a solvent, m-fluorobenzotrifluoride and nitric acid are used for nitration reaction. The molar ratio of m-fluorobenzotrifluoride to nitric acid is 1.0: 2.0, and the reaction temperature is 30°C. The reaction produces 4-fluoro- 2-trifluoromethylnitrobenzene;

[0040](2) Bromination: use sulfuric acid as solvent and dibromohydantoin as bromination reagent, wherein the molar ratio of 4-fluoro-2-trifluoromethylnitrobenzene to dibromohydantoin is 1.4:1.0, and the reaction temperature It is 25°C; the bromination reaction in this step yields 3-bromo-4-fluoro-2-trifluoromethylnitrobenzene, 5-bromo-4-fluoro-2-trifluoromethyl Brominated mixtures of nitrobenzene;

[0041] (3) Reduction: In the water phase, acetic aci...

Embodiment 3

[0045] Example 3, a preparation method of 2-bromo-3-fluorobenzoic acid, which uses m-fluorobenzotrifluoride as a raw material, and finally obtains the target product 2- Bromo-3-fluorobenzoic acid; the procedure is as follows:

[0046] (1) Nitration: Using sulfuric acid as a solvent, m-fluorobenzotrifluoride and nitric acid are used for nitration reaction. The molar ratio of m-fluorobenzotrifluoride to nitric acid is 1.0:1.8, and the reaction temperature is 25°C. The reaction produces 4-fluoro- 2-trifluoromethylnitrobenzene;

[0047] (2) Bromination: use sulfuric acid as solvent and dibromohydantoin as bromination reagent, wherein the molar ratio of 4-fluoro-2-trifluoromethylnitrobenzene to dibromohydantoin is 1.3:1.0, and the reaction temperature It is 22°C; the bromination reaction in this step yields 3-bromo-4-fluoro-2-trifluoromethylnitrobenzene, 5-bromo-4-fluoro-2-trifluoromethyl Brominated mixtures of nitrobenzene;

[0048] (3) Reduction: In the water phase, acetic aci...

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Abstract

The invention relates to a preparation method of 2-bromine-3-fluorobenzoic acid. According to the method, fluorobenzotrifluoride is used as a material and is subjected to nitration, bromination, reduction, deamination, separation and hydrolysis to finally obtain a target product, namely the 2-bromine-3-fluorobenzoic acid. During the nitration, sulfuric acid is taken as a solvent, and 4-fluorine-2-trifluoromethyl nitrobenzene is obtained after reaction; during the bromination, sulfuric acid is taken as a solvent and dibromohydantoin is taken as a bromination reagent; during the reduction, acetic acid or ammonium chloride is taken as a catalyst in a water phase, and reduced iron powder is used for carrying out reduction reaction; the deamination is carried out in phosphorous acid; during the separation, 2-bromine-3-fluorine trifluorotoluene is obtained by decompression and fractionation of a rectifying column; and the hydrolysis is carried out by adding sulfuric acid to a reaction kettle. The method disclosed by the invention is relatively reasonable in design, low in cost of the material, easy to get the material, and mild, simple and safe in process conditions of the preparation reaction, and the yield is high.

Description

technical field [0001] The invention relates to a method for synthesizing a pharmaceutical intermediate compound, in particular to a method for preparing 2-bromo-3-fluorobenzoic acid. Background technique [0002] 2-Bromo-3-fluorobenzoic acid is a new type of fluorine-containing drug intermediate. Some methods for preparing 2-bromo-3-fluorobenzoic acid and its analogues have been reported in the existing literature: such as PCT Int. Appl., 2008154221, 18 Dec, 2008 reported that 2-amino-3-fluorobenzene Formic acid is used as a raw material, diazotized in hydrobromic acid to obtain the diazonium salt and then reacted with cuprous bromide to obtain the target product, but the preparation of the starting material 2-amino-3-fluorobenzoic acid is very difficult and expensive, resulting in the target Product cost is difficult to reduce. Its reaction scheme is as follows: [0003] [0004] Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemist...

Claims

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Application Information

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IPC IPC(8): C07C63/70C07C51/093
CPCC07C51/093C07C63/70
Inventor 陈卫东
Owner 陈卫东
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