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Preparation method of L-carnitine

The technology of L-carnitine and catalyst is applied in the field of preparation of chiral substances, which can solve problems such as environmental pollution, and achieve the effects of less environmental pollution, easy availability of raw materials and low pressure.

Active Publication Date: 2014-05-28
GUANGXI XINJING TECH +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The object of the present invention is to provide a kind of technology that is used for preparing L-carnitine with high reactivity, low pressure of hydrogenation reaction, simple operation, low cost, less environmental pollution, thereby solves the problem that still needs to be used heavily in the current domestic production of L-carnitine Poisonous cyanide, environmental pollution problem

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Example 1: Preparation of catalyst [RuCl(cymene)(S-BINAP)]Cl.

[0026] Get the chiral ligand S-BINAP (0.535g, 0.85mmol) and ruthenium compound [Ru(p-cymene)Cl 2 ] 2 (0.29g, 0.47mmol) in the three-necked bottle, under N 2 Add absolute ethanol 60mL and CH under protection 2 Cl 2 20mL, heated to 50-60°C and stirred for 20h. After removing the solvent under reduced pressure, 0.87g of reddish-brown product [RuCl(cymene)(S-BINAP)]Cl[chloro[(S)-(-)-2, 2'-bis(diphenylphosphine)-1,1'-binaphthyl](p-cymenyl)ruthenium(II) chloride].

Embodiment 2

[0027] Example 2: Preparation of intermediate (R)-(-)-4-chloro-3-hydroxybutyric acid ethyl ester.

[0028] Take 80g of ethyl 4-chloroacetoacetate in an autoclave equipped with a Teflon liner, and after the autoclave is closed, use 5kgf / cm 2 of pure H 2 (99.99%) After washing the autoclave more than 10 times, fill the autoclave with hydrogen for use. in H 2 Dissolve the catalyst [RuCl(cymene)(S-BINAP)]Cl (30 mg) in 300 mL of ethyl acetate solution under the atmosphere, carefully add it into the autoclave with a syringe, and continue to charge hydrogen to 5 kgf / cm 2 Finally, raise the temperature to about 80°C, let it stand for about 20 minutes, then start stirring, react at this temperature for 6 hours, stop the reaction, take out the material, and remove the lower alkyl ester solvent by vacuum distillation to obtain a high-purity product. The product was analyzed by GC. The conversion rate is greater than 99%, and the ee value is 96%.

Embodiment 3

[0029] Example 3: Preparation of intermediate (R)-(-)-4-bromo-3-hydroxybutyrate butyl ester.

[0030]Take 80g of 4-butyl bromoacetoacetate in an autoclave equipped with a polytetrafluoroethylene liner, and after the autoclave is closed, use 3kgf / cm 2 of pure H 2 (99.99%) After washing the autoclave more than 10 times, fill the autoclave with hydrogen for use. in H 2 Dissolve the catalyst [RuCl(cymene)(S-BINAP)]Cl (3 mg) in 300 mL of propyl acetate solution under atmosphere, carefully add it into the autoclave with a syringe, and continue to charge hydrogen to 3 kgf / cm 2 Afterwards, raise the temperature to about 120°C, let it stand for about 60 minutes, start stirring, react at this temperature for 10 hours, stop the reaction, take out the material and remove the lower alkyl ester solvent by vacuum distillation to obtain a high-purity product. The product was analyzed by GC. The conversion rate was 100%, and the ee value was 96%.

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Abstract

The invention relates to a method for preparing L-carnitine by asymmetric catalytic hydrogenation reduction. Alkyl 4-chloroacetoacetate is used as a raw material, [RuCl(cymene)(S-BINAP)]Cl[chloro[(S)-(-)-2,2'-di(diphenylphosphine)-1,1'-binaphthyl](p-cymene)ruthenium chloride(II))] is used as a catalyst, and amination and hydrolysis reaction are carried out to obtain the L-carnitine product. The amination reaction does not need any solvent or virulent cyanide. The chemical purity of the L-carnitine product is higher than 97%, and the specific rotation [alpha]20D is -29 -32. The invention has the advantages of high reaction speed, stable catalytic system, low pressure required by the reaction process, high conversion rate, no need of solvent in the amination reaction, and is convenient to operate, thereby lowering the cost, reducing the environmental pollution and being convenient for large-scale production.

Description

technical field [0001] The invention relates to a preparation method of a chiral substance. More specifically, it is a method for preparing L-carnitine by asymmetric catalytic hydrogenation reduction. Background technique [0002] L-carnitine or L-carnitine, also known as L-carnitine or vitamin BT, its chemical name is β-hydroxy γ-trimethylammonium butyric acid, which is a white lens or white transparent fine powder. Carnitine research began in the early 20th century. In 1905, the Russians Gulewitsch and Krimberg discovered L-carnitine from meat extracts. Since then, scientists from various countries have conducted in-depth research. Early studies have found that L-carnitine is a vitamin-like nutrient and named it vitamin BT. In fact, the chemical structure of carnitine is similar to choline, which is similar to amino acids; in addition, because some animals can synthesize carnitine by themselves, it is considered that carnitine is not a vitamin, but it is still customari...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C229/22C07C227/32B01J31/24
Inventor 孙果宋韦志明阮恒黄科润黄平覃兰华穆允玲董振荣高景星李岩云
Owner GUANGXI XINJING TECH
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