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Method for preparing N-ethoxy oxalyl alanine ethyl ester

A technology of ethoxyoxalylalanine ethyl ester and diethyl oxalate, which is applied in the field of preparing synthetic vitamin B6 intermediate N-ethoxyoxalylalanine ethyl ester, can solve heavy environmental pollution and inconvenient operation , low reaction yield and other problems

Active Publication Date: 2014-03-26
HUBEI HUISHENG PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the low activity of the inorganic salt catalyst, the reaction yield is low, about 85%, the equipment is seriously corroded, the content and yield are low, the cost is high, the environmental pollution is serious, the operation is inconvenient, and the product has many impurities.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Add 59.1g (0.663mol) of alanine, 126g (1mol) of industrial oxalic acid, and 300g of 95% ethanol into a four-necked flask with a rectification column water separator and a condenser device, heat to 80°C to dissolve, and then add The catalyst is a mixture of 3.2g (0.02mol) of concentrated sulfuric acid and urea, 130g of benzene, and 150g of diethyl oxalate, heated to 85°C for rectification, dehydration and esterification for 24 hours (the moisture in the reaction solution is detected to be less than 0.1%). Add 100g of water and 140g of benzene to the above reaction solution, stir for 30 minutes, separate the water layer at rest, heat the organic layer at normal pressure to recover benzene to an internal temperature of 130°C, and recover diethyl oxalate under reduced pressure until it reaches 150°C / 0.095MPa. get yellowish N - Ethoxyoxalylalanine ethyl ester 142.5g, content 96%, yield 95.0%.

Embodiment 2

[0031] In a four-neck flask equipped with a rectification column water separator and a condenser device, add 59.1g (0.663mol) of alanine, 126g (1mol) of industrial oxalic acid, and 100g of 95% ethanol, heat to 80°C to dissolve, and then add The catalyst is a mixture of 3.2g (0.02mol) of concentrated sulfuric acid and urea, 130g of benzene, and 150g of diethyl oxalate, heated to 65°C for rectification, dehydration and esterification for 60 hours (the moisture in the reaction solution is detected to be less than 0.1%). Add 100g of water and 140g of benzene to the above reaction solution, stir for 30 minutes, separate the water layer at rest, heat the organic layer at normal pressure to recover benzene until the internal temperature reaches 130°C, and recover diethyl oxalate under reduced pressure until it reaches 150°C / 0.095MPa , to get pale yellow N - Ethoxyoxalylalanine ethyl ester 139.4g, content 93%, yield 90%.

Embodiment 3

[0033] Catalyst The mixture 2.4g (0.015mol) of concentrated sulfuric acid and urea Other steps are identical with embodiment 1, obtain pale yellow N - Ethoxyoxalylalanine ethyl ester 137.9g, content 95%, yield 91%.

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Abstract

The invention discloses a method for preparing N-ethoxy oxalyl alanine ethyl ester. The method comprises the following steps: heating and dissolving alanine, oxalic acid and alcohol, and then adding a catalyst, a water-carrying agent benzene and diethyl oxalate, wherein the catalyst is a mixture of sulfuric acid and urea in a molar ratio of 1: (1-3); heating the obtained mixture to 60-100 DEG C; carrying out reflux rectification reaction for 10-150 hours, wherein in the process of reaction, the water produced in the process of reaction is timely evaporated by using the water-carrying agent benzene; and after the reaction is finished, carrying out after-treatment so as to obtain a target product, namely, the N-ethoxy oxalyl-alanine ethyl ester. Compared with the prior art, the method disclosed by the invention has the following advantages that: the catalyst is the mixture of sulfuric acid and urea, therefore, the catalyst has acidity catalytic activity and contains ammonium salt cations, and the ammonium salt cations can be adsorbed on the surface of metal, thereby reducing the corrosion of the catalyst on equipment; and meanwhile, the catalytic efficiency is high, the reaction yield is high, and the side reaction is less.

Description

technical field [0001] The present invention relates to synthetic vitamin B 6 field, and more particularly relates to a method for the preparation of synthetic vitamin B 6 A method for the intermediate N-ethoxyoxalylalanine ethyl ester. Background technique [0002] N-ethoxyoxalylalanine ethyl ester is a synthetic vitamin B 6 main raw material. [0003] At present, in the industry, alanine, oxalic acid, ethanol, etc. are generally used as raw materials to synthesize N-ethoxy oxalyl alanine through ester acylation under the catalysis of concentrated hydrochloric acid or hydrochloric acid-phosphoric acid or bisulfate or non-organic bases. ethyl acetate. for example: [0004] U.S. Patent No. 3,646,061 discloses a preparation method of ethoxyoxalylalanine ethyl ester, which puts alanine, oxalic acid, and ethanol together. After a certain period of time, the unreacted ethanol and the generated The water is distilled out, then ethanol is added, heated, and unreacted ethano...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C233/56C07C231/14
Inventor 陈先保
Owner HUBEI HUISHENG PHARMA
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