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Racemization method for alpha-chiral carboxylic acid

A chiral carboxylic acid and racemization technology, which is applied in the fields of carboxylate preparation, organic chemistry methods, chemical instruments and methods, etc., can solve the problems of long time consumption, high energy consumption in the concentration step, and many bases for racemization, and achieves the The effect of reducing consumption, saving energy and reducing corrosion

Inactive Publication Date: 2015-03-18
ZHEJIANG TIANXIN PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the disadvantages of the existing α-chiral carboxylic acid racemization process, such as the large number of racemization bases, large energy consumption and long time consumption in the concentration step, and provide a method that uses less base and does not need to be concentrated. Step-by-step racemization of α-chiral carboxylic acids with low energy consumption

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] This example is used to illustrate the racemization method of α-chiral carboxylic acid provided by the present invention.

[0022] Put 50 g of R-6-methoxy-α-methyl-2-naphthaleneacetic acid into the autoclave, add 500 ml of water, and add 43 g of 30% by weight NaOH aqueous solution under stirring. Cover the lid of the kettle, stir and raise the temperature to 135°C, increase the pressure to 0.38MPa, and keep the temperature for 2 hours. After the heat preservation is over, transfer the material to a three-necked flask, raise the temperature to 75±5°C, adjust the pH to 7-8 with hydrochloric acid, add 1g of activated carbon, and keep warm at the same temperature for 30 minutes for decolorization. Remove activated carbon by filtration, adjust pH to 2-3 with hydrochloric acid, cool to room temperature, filter, wash with water until neutral, and dry to obtain (±)-6-methoxy-α-methyl-2-naphthaleneacetic acid 49.2g . Detection specific rotation The content is 98.7%, and the ...

Embodiment 2

[0030] This example is used to illustrate the racemization method of α-chiral carboxylic acid provided by the present invention.

[0031] Put 50 g of R-6-methoxy-α-methyl-2-naphthaleneacetic acid into the autoclave, add 300 ml of water, and add 58 g of an aqueous solution with a concentration of 30% by weight of NaOH under stirring. Cover the lid of the kettle, raise the temperature to 115°C, increase the pressure to 0.2MPa, and keep the temperature for 4 hours. After the heat preservation is over, transfer the material to a three-necked flask, raise the temperature to 75±5°C, adjust the pH to 7-8 with hydrochloric acid, add 1g of activated carbon, and keep warm at the same temperature for 30 minutes for decolorization. Remove activated carbon by filtration, adjust pH to 2-3 with hydrochloric acid, cool to room temperature, filter, wash, and dry to obtain 49.3 g of (±)-6-methoxy-α-methyl-2-naphthaleneacetic acid. Detection specific rotation The content is 98.8%, and the racem...

Embodiment 3

[0033] This example is used to illustrate the racemization method of α-chiral carboxylic acid provided by the present invention.

[0034] 100.0 g of S-2-methylbutyric acid was put into an autoclave, 400 ml of water was added, and 144 g of a 30% by weight NaOH aqueous solution was added with stirring. Cover the lid of the kettle, stir and raise the temperature to 135°C, raise the pressure to 0.4MPa, and keep the temperature for 5 hours. At the end of the heat preservation, transfer the material to a three-necked flask, adjust the pH to 1-2 with hydrochloric acid, let it stand, separate the liquid to remove the water layer, and purify the oil layer by vacuum distillation to obtain (±)-2-methylbutyric acid 95.2 g. Detection specific rotation The content is 99.2%, and the racemization yield is 95.2%.

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Abstract

The invention discloses a racemization method for alpha-chiral carboxylic acid; the method comprises the following steps: enabling alpha-chiral carboxylic acid with an optical activity, water and alkali to contact at 108-140 DEG C and under 0.11-0.5MPa, and reacting for 1-5hr to obtain a racemic product with racemization yield higher than 95%. The racemization method adopted by the invention is carried out under high pressure, and is fast in temperature rising and low in alkali consumption; the racemization method not only avoids shortcomings of a conventional process which is long in duration and high in energy consumption caused by temperature rising by virtue of water evaporating and concentrating, but also reduces alkali consumption for racemization; and corrosion of a high-alkalinity material mixing solution on racemization reaction equipment is avoided.

Description

technical field [0001] The invention relates to a racemization method of α-chiral carboxylic acid. Background technique [0002] α-Chiral carboxylic acid refers to an alkyl or aryl carboxylic acid whose α-position carbon atom is a chiral carbon atom. Due to its special physical, chemical and physiological properties, it is widely used in the field of biomedicine. During use, the two enantiomers of α-chiral carboxylic acids often exhibit different physiological functions. For example, the commonly used non-steroidal anti-inflammatory drug 6-methoxy-α-methyl-2-naphthaleneacetic acid. Pharmacological experiments show that the physiological activity of the S-enantiomer is 27.5 times that of the R-enantiomer, so it is the S-isomer of the drug that is used clinically. In addition to the difference in physiological activity, the toxic and side effects of the two enantiomers are often also different. For example, there is a potential acylation reaction between the acyl glucuronic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07B55/00C07C51/00C07C59/64C07C53/128C07C57/30C07C59/84C07C57/58
Inventor 徐勇智章根宝范卫东张平张晓增洪丰庆
Owner ZHEJIANG TIANXIN PHARMA
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