Method for enzymatically synthesizing chiral acetic cyanhydrin ester by directly using cyanogen salt as cyanogens source

A cyanohydrin acetate and a technology using cyanide salts are applied in the field of enzyme-catalyzed synthesis of chiral cyanohydrin acetate, which can solve the problems of decreased optical purity of the product, loss of application value and the like, and achieves the effects of high industrial application value and simple method.

Inactive Publication Date: 2012-04-18
EAST CHINA NORMAL UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, chiral hydrocyanation reactions directly using low-volatility cyanide salts KCN or NaCN as cyanogen donors are prone to spontaneous non-enzymatic chemical addition reactions with aldehydes and compete with enzyme-catalyzed reactions, It leads to the formation of racemic products, the optical purity of the products decreases, and the practical application value is lost
[0005] Further, the product chiral cyanohydrin generated by the reaction will also lead to racemization due to the reversible reaction, which will reduce the optical purity of the product.

Method used

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  • Method for enzymatically synthesizing chiral acetic cyanhydrin ester by directly using cyanogen salt as cyanogens source
  • Method for enzymatically synthesizing chiral acetic cyanhydrin ester by directly using cyanogen salt as cyanogens source
  • Method for enzymatically synthesizing chiral acetic cyanhydrin ester by directly using cyanogen salt as cyanogens source

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Embodiment 1

[0022] Embodiment 1: ( R )-α-Acetoxy-2-Phenylacetonitrile Preparation

[0023] Add 1 g of almond enzyme, 6 mmol of NaCN, and 7 mmol of acetic acid to 1 mL of water and 9 mL of ethyl acetate, stir well, add 3 mmol of benzaldehyde dropwise, and react for 48 hours; the organic phase obtained after liquid separation is added dropwise to In a mixture containing 6 mmol acetic anhydride and 6 mmol pyridine, react at room temperature for 3 hours. After being washed with saturated sodium bicarbonate and water, dried, concentrated and purified by column chromatography, the target compound was obtained, and the chemical yield was calculated. The content of the two optical isomers of the product was determined by a chiral chromatographic column and the enantiomeric excess percentage (ee value) was calculated. The results are shown in Table 1.

Embodiment 2

[0024] Embodiment 2: ( R )-α-Acetoxy-2-(4-methoxyphenyl)acetonitrile

[0025] In 5 mL of water and 5 mL of ethyl acetate, add 1 g of almond enzyme, 6 mmol of KCN, and 10 mmol of acetic acid, stir well, add 3 mmol of 4-methoxybenzaldehyde dropwise, and react for 24 hours; The organic phase was added dropwise to a mixture containing 6 mmol acetic anhydride and 6 mmol pyridine, and reacted at room temperature for 5 hours. After being washed with saturated sodium bicarbonate and water, dried, concentrated and purified by column chromatography, the target compound was obtained, and the chemical yield was calculated. The content of the two optical isomers of the product was determined by a chiral chromatographic column and the enantiomeric excess percentage (ee value) was calculated. The results are shown in Table 1.

Embodiment 3

[0026] Embodiment 3: ( R )-α-Acetoxy-2-(3-methoxyphenyl)acetonitrile preparation

[0027] Add 1.5 g of laetrile, 5 mmol of NaCN, and 5 mmol of acetic acid to 5 mL of water and 5 mL of toluene, stir well, add 3 mmol of 3-methoxybenzaldehyde dropwise, and react for 48 hours; the organic phase obtained after liquid separation Add it dropwise to a mixture containing 10 mmol acetic anhydride and 10 mmol pyridine, and react at room temperature for 24 hours. After being washed with saturated sodium bicarbonate and water, dried, concentrated and purified by column chromatography, the target compound was obtained, and the chemical yield was calculated. The content of the two optical isomers of the product was determined by a chiral chromatographic column and the enantiomeric excess percentage (ee value) was calculated. The results are shown in Table 1.

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Abstract

The invention discloses a method for enzymatically synthesizing chiral acetic cyanhydrin ester by directly using cyanogen salt as a cyanogens source. The method includes the following steps: enzyme, the cyanogen salt, water, organic solvent and acetic acid are sequentially added into a reaction vessel and uniformly mixed, aldehyde compound is dripped, reaction takes place under the condition of room temperature, and the reaction time is 6 to 100 hours; after the reaction is finished, separated organic phase is dipped into mixture containing acetic anhydride and pyridine to react under the room temperature for 3 to 24 hours; and after saturated sodium bicarbonate and water washing, drying, concentration and column chromatography purification, the corresponding target compound is obtained. The method directly uses the cyanogen salt as the cyanogens source and the cheap, easy-to-obtain acetic acid as a proton donor, and effectively inhibits the spontaneous chemical addition reaction of HCN and aldehyde ketone by controlling the proportion between the water and the organic phase, so that enzymatic reaction under hydroxynitrile lyase can be efficiently carried out. The method is simple and safe, can obtain high yield of high-optical purity chiral acetic cyanhydrin ester, and has high industrial application value.

Description

technical field [0001] The invention relates to a method for enzymatically synthesizing chiral cyanohydrin acetate directly using cyanide salt (MCN) as a cyanogen source. Specifically: directly use low-volatility cyanide salt (MCN) instead of highly toxic volatile hydrogen cyanide gas as the cyanide source; use cheap and easy-to-obtain acetic acid as the proton donor, which can also replace the buffer system usually required, and control properly The water-organic phase ratio can effectively inhibit the spontaneous chemical addition reaction of HCN and aldehydes and ketones, so that the enzymatic reaction of cyanohydrin lyase can be carried out efficiently, and the product with high optical purity can be obtained in high yield. Further, through a simple and continuous acetylation reaction, a relatively stable chiral cyanohydrin acetate is generated, which avoids the phenomenon that the chiral cyanohydrin is usually prone to reverse reactions and causes racemization, which redu...

Claims

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Application Information

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IPC IPC(8): C12P13/00C12P17/04C12P17/00C12P17/06
Inventor 邹新琢郑祖彪姚璐璐李中洲
Owner EAST CHINA NORMAL UNIVERSITY
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