Method for preparing levocysteine and dextral cysteine using chemical resolution method

A technology of L-cysteine ​​and cysteine, which is applied in the field of preparation of L-cysteine ​​and D-cysteine, can solve the problems of low product yield and the like, and achieves simple synthesis process and little environmental pollution. , the effect of reducing the dosage

Inactive Publication Date: 2006-12-13
安徽省恒锐新技术开发有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The invention adopts L-mandelic acid to split racemic cysteine ​​so that the yield of L-cysteine ​​is about 20%, the product yield is relatively low, and it does not involve the synthesis of D-cysteine

Method used

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  • Method for preparing levocysteine and dextral cysteine using chemical resolution method
  • Method for preparing levocysteine and dextral cysteine using chemical resolution method
  • Method for preparing levocysteine and dextral cysteine using chemical resolution method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] DL-Cys2.43g (0.02mol) was dissolved in 20ml of dilute hydrochloric acid, heated to 80-100°C under stirring, added L-DBTA3.58g (0.01mol), reacted at this temperature for half an hour, and then kept at 60°C After 1 hour, a precipitate gradually formed, then cooled to about 15°C, filtered with suction, dissolved the filter cake in 30ml of ethanol and 2 times the amount of triethylamine, stirred for 1 hour, filtered with suction, washed with ethanol, and dried to obtain 1.06g L -Cys, resolution yield 87.5%, [α] D 20=+8.7° (C=8, 1N HCl), the optical purity of L-Cys product is 99.3%. Split and concentrate the mother liquor, adjust the pH value to 5.5 with alkali, stir, a white solid precipitates out, filter with suction and wash with ethanol, dry to obtain 0.96g of D-Cys, the yield is 79.2%, [α] D 22 =-8.6° (C=8, 1N HCl), the optical purity of the D-Cys product is 99.2%.

Embodiment 2

[0040] DL-Cys2.43g (0.02mol) was dissolved in 20ml dilute hydrochloric acid, stirred, heated to 90-100°C, added 3.58g D-DBTA, reacted at this temperature for 50 minutes, then kept at 60°C for 1 hour, gradually precipitated formed, then cooled to about 15°C, filtered with suction and washed with water, dissolved the filter cake in 30ml of ethanol and 2 times the amount of triethylamine, stirred for 1 hour, filtered with suction, washed with ethanol, and dried to obtain 1.06g of D-Cys. Resolution yield 87.5%, [α] D 22 =-8.8° (C=8, 1N HCl), the optical purity of the D-Cys product is 99.5%. . Split and concentrate the mother liquor, adjust the pH value to 5.5 with alkali, stir, a white solid precipitates, filter with suction and wash with ethanol, dry to obtain 0.94g L-Cys, yield 77.4%, [α] D 22 =+8.7° (C=8, 1N HCl), the optical purity of the D-Cys product is 99.3%.

Embodiment 3

[0042] DL-Cys2.43g (0.02mol) was dissolved in 20ml of dilute hydrochloric acid, heated to 80-100°C under stirring, added L-DBTA7.16g (0.02mol), reacted at this temperature for half an hour, and then kept at 60°C After 1 hour, a precipitate gradually formed, then cooled to about 15°C, filtered with suction, dissolved the filter cake in 30ml of ethanol and 2 times the amount of triethylamine, stirred for 1 hour, filtered with suction, washed with ethanol, and dried to obtain 1.08g L -Cys, resolution yield 88.9%, [α] D 20 =+8.8° (C=8, 1N HCl), the optical purity of L-Cys product is 99.5%. Split and concentrate the mother liquor, adjust the pH value to 5.5 with alkali, stir, a white solid precipitates out, filter with suction and wash with ethanol, dry to obtain 0.90 g of D-Cys, the yield is 74.1%, [α] D 22 =-8.6° (C=8, 1N HCl), the optical purity of the D-Cys product is 99.2%.

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Abstract

The invention relates the method of preparing L-Cys and D-Cys with chemical resolution method, comprising the following steps: using DL-Cys as raw material, using inorganic acid as dissolvent, using D-DBTA and L-DBTA as resolution agent, dissolving the DL-Cys and resolution agent at the rate of 1:0.5-1.2 in the dilute inorganic acid solution, stirring for 0.5-2.0 hours at the temperature 60-100Deg.C, cooling, filtering, neutralizing crystallization salt and mother liquid with alkali, and separately getting L-Cys and D-Cys. The invention has the advantages of simple technology. The resolution agent can be recovered.

Description

technical field [0001] The invention relates to a preparation technology of chiral organic compounds, in particular to a preparation method of L-cysteine ​​and D-cysteine. Background technique [0002] Cysteine, also known as 2-amino-3 mercaptopropionic acid. Cysteine ​​is a neutral amino acid containing sulfhydryl groups, that is, its amino and carboxyl groups have the same number. It has a chiral carbon atom in its molecular structure, that is, a chiral center, so it has a pair of enantiomers, namely L-cysteine ​​(L-Cys) and D-cysteine ​​(D- Cys), its structure is as follows: [0003] [0004] L-cysteine ​​(L-Cys) D-cysteine ​​(D-Cys) [0005] Both L-cysteine ​​and D-cysteine ​​are important compounds that can be widely used in medicine, food, cosmetics, feed and other industries. L-cysteine ​​is mainly extracted from the hydrolysis products of natural substances, such as human hair and animal hair. At present, this technology has been widely used in the production ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C323/58C07C319/28C07B57/00
Inventor 马云峰柴多里王组元吴梅
Owner 安徽省恒锐新技术开发有限责任公司
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