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A preparation method for 4-methoxy-2-nitrobenzoic acid

A technology of methoxybenzoic acid and methoxylation, which is applied in the preparation of nitro compounds, the preparation of carboxylic acid nitrile, the preparation of amino compounds, etc., can solve the problems of complicated process treatment and low product yield, etc.

Inactive Publication Date: 2019-04-02
CHANGZHOU UNIV
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Problems solved by technology

CN103113349 reported that o-cresol was used as a raw material to synthesize the target substance through nitration, methoxylation and oxidation, and the product yield was relatively low, and the process treatment was relatively complicated

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  • A preparation method for 4-methoxy-2-nitrobenzoic acid

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[0024] (1) Nitration reaction: Add 1400 g of p-difluorobenzene and 5800 mL of sulfuric acid into the reaction vessel, and control the temperature at about 5 °C. Add potassium nitrate 1450 g in batches. After the reaction is over, GC tracks until the reaction is complete. After the reaction was completed, it was analyzed with ice water and filtered with suction to obtain 1620 g of off-white solid 2,5-difluoronitrobenzene with a content of 99% and a yield of 83%.

[0025] (2) Ammonolysis reaction: Add 6000 mL of DMSO and 1200 g of raw material 2,5-difluoronitrobenzene into the reactor, stir, heat, control the temperature at 80-100 °C, pass ammonia, and track by GC until the reaction is complete , slightly cooled, water analysis, and suction filtration to obtain 1108 g of light yellow solid 2-nitro-4-fluoroaniline, the content was greater than 98%, and the yield was 94%.

[0026] (3) Bromine reaction on diazo: Add 1100 g of 2-nitro-4-fluoroaniline to the reaction vessel, then a...

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Abstract

An industrial preparation method for 4-methoxy-2-nitrobenzoic acid is disclosed. In the method, p-difluorobenzene is adopted as an initial raw material and subjected to nitration, ammonolysis, diazotization bromination, cyaniding, methoxylation and hydrolysis which are six steps to synthesize the 4-methoxy-2-nitrobenzoic acid. The 4-methoxy-2-nitrobenzoic acid obtained by the method is white powdered solid with purity being 98.5%, the raw material conversion ratio in each step is 100%, and the total yield of the whole process is 35.8%.

Description

technical field [0001] The present invention relates to a kind of production method of pharmaceutical intermediate, specifically, the present invention is a kind of preparation method of 2-nitro-4-methoxybenzoic acid. Background technique [0002] At present, 2-nitro-4-methoxybenzoic acid is mainly used in the pharmaceutical industry. For example, it can be used for: 1) 4-imidazolylquinoline compounds of synthetase inhibitors 2) indole carboxamide derivatives of p2x7 receptor antagonists 3) synthesis of substituted benzimidazole compounds as COT kinase inhibitors to treat inflammation and cancer and other diseases 4) Synthesis of thiadiazole compounds as protein kinase B modulators. [0003] At present, there are three methods for the synthesis of 2-nitro-4-methoxybenzoic acid. CN103113349 reports that o-cresol is used as a raw material to synthesize the target product through nitration, methoxylation and oxidation, but the product yield is relatively low and the process t...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/12C07C205/59
CPCC07C201/08C07C201/12C07C209/10C07C253/14C07C253/30C07C205/59C07C255/54C07C255/50C07C205/12C07C211/52
Inventor 陈兴权董燕敏
Owner CHANGZHOU UNIV