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Method for producing 2-bromo-4,5-dialkoxy benzoic acid

A technology of dialkoxybenzoic acid and manufacturing method, applied in the direction of carboxylate preparation, organic chemical method, chemical instrument and method, etc., can solve the problem of using a large amount of organic solvents, etc., and achieve the effect of low price

Active Publication Date: 2013-08-07
ZERIA PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, there is a problem that organic solvents must be used in large quantities

Method used

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  • Method for producing 2-bromo-4,5-dialkoxy benzoic acid
  • Method for producing 2-bromo-4,5-dialkoxy benzoic acid
  • Method for producing 2-bromo-4,5-dialkoxy benzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] (Compound (1)→Compound (2))

[0051]25.0 g of 3,4-dimethoxybenzoic acid was suspended in 500 mL of concentrated hydrochloric acid (35%), and 23.0 g (1.05 equivalent) of bromine was added dropwise at 25°C. Then, it was stirred for 7 hours. After adding 500 mL of water and stirring for 1 hour, the crystals were filtered out. After drying under reduced pressure, 34.47 g of crude crystals of 2-bromo-4,5-dimethoxybenzoic acid were obtained in a yield of 96.2%.

[0052] 1 H-NMR (DMSO-d 6 , δ): 3.79 (s, 3H), 3.84 (s, 3H), 7.21 (s, 1H), 7.37 (s, 1H), 13.08 (bs, 1H).

[0053] In the above reaction, the reaction was carried out in the same manner while changing the amount of bromine, the reaction temperature, and the reaction time. Table 1 shows the relationship between these reaction conditions and the yield. In Table 1, A represents 3-bromo-4,5-dimethoxybenzoic acid, B represents 3,4-dimethoxybenzoic acid, and C represents 1,2-dibromo-4,5-dimethoxy phenyl, E and F repres...

Embodiment 2

[0063] (Compound (2)→Compound (3))

[0064] 80 mL of water was added to 20.0 g of crude crystals of 2-bromo-4,5-dimethoxybenzoic acid obtained in Example 1 and 10.1 g of sodium carbonate. It heated and stirred to 80 degreeC, and the copper sulfate solution prepared separately from 1.91 g of copper sulfate pentahydrates, 20 mL of water, and 3.1 mL of pyridines was added. Furthermore, it heated and stirred at 90-100 degreeC for 1 hour. After cooling to 50°C, 16.0 g of concentrated hydrochloric acid was added dropwise. After cooling, the crystals were filtered out and dried under reduced pressure to obtain 15.08 g of crude crystals of 2-hydroxy-4,5-dimethoxybenzoic acid in a yield of 99.3%.

[0065] 1 H-NMR (DMSO-d 6 , δ): 3.71 (s, 3H), 3.81 (s, 3H), 6.56 (s, 1H), 7.17 (s, 1H), 11.22 (bs, 1H), 13.58 (bs, 1H).

[0066] The same reaction as in Example 2 was performed using various copper compounds equivalent to copper sulfate instead of copper sulfate. The reaction conditions...

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Abstract

Provided is a method for effectively producing a 4,5-dialkoxy-2-hydroxybenzoic acid from an inexpensive raw material. A method for producing a 2-bromo-4,5-dialkoxybenzoic acid represented by the following formula (2): (wherein each of R1 and R2 represents a lower alkyl group), the method including causing a 3,4-dialkoxybenzoic acid represented by the following formula (1): (wherein R1 and R2 have the same meanings as defined above) to react with bromine in concentrated hydrochloric acid.

Description

technical field [0001] The present invention relates to a method for producing 2-bromo-4,5-dialkoxybenzoic acid useful as a synthetic intermediate for pharmaceuticals and the like. Background technique [0002] 4,5-Dialkoxy-2-hydroxybenzoic acid (3) is known as a raw material and a synthetic intermediate of various pharmaceuticals or agricultural chemicals, and the following method is known as a production method, that is, the following reaction formula As shown, the Lewis acid is reacted with 2,4,5-trialkoxybenzoic acid (a) in an ester-based, ketone-based or amide-based solvent to selectively demethylate the 2-position methoxy group Kylation (Patent Document 1). [0003] [0004] (where, R 1 and R 2 Each independently represents a lower alkyl group) [0005] prior art literature [0006] patent documents [0007] Patent Document 1: International Publication No. WO2006 / 022252 Pamphlet [0008] Patent Document 2: Japanese Patent Laid-Open No. 2003-252826 Contents ...

Claims

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Application Information

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IPC IPC(8): C07C51/363C07C51/367C07C65/21C07B61/00
CPCC07C51/367C07C51/363C07C65/21C07B61/00
Inventor 中尾龙
Owner ZERIA PHARMA
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