Asymmetric synthesis method of l-carnitine

A synthetic method and asymmetric technology, applied in the fields of medicinal chemistry and organic chemistry, can solve the problems of long reaction steps, high risk, toxic tin compounds, etc., and achieve the effect of low cost, simple method and high selectivity

Active Publication Date: 2020-11-17
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] This method may eliminate two chlorine atoms when opening the ring, and also uses a toxic tin compound, and the reaction steps are relatively long; Paul (US 2015 / 0126775A1, US 8563752B2) et al. Ning derivatives and other chiral catalysts and Lewis acid co-catalyzed asymmetric synthetic routes, although this route has been improved to a certain extent, ideal products and yields can be obtained, but the risk of industrial production of this method is very high, due to ethylene Ketone is easy to polymerize into diketene, which is easily deteriorated and lost during storage, and is also prone to leakage during use. Therefore, people have been looking for simple, safe and efficient production methods to reduce production costs and benefit mankind.

Method used

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  • Asymmetric synthesis method of l-carnitine
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  • Asymmetric synthesis method of l-carnitine

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The synthetic method of L-carnitine is realized through the following steps:

[0027] 1) Preparation of β-chiral lactone

[0028] Under nitrogen protection, add dichloromethane (100ml) and acetyl chloride (39.3g, 0.5mol) to a 500ml double-layer reaction flask (equipped with nitrogen protection, stirring and dropping funnel), and cool the liquid to -50°C. DBU (76.1g, 0.5mol) was added dropwise, the drop was completed, and the temperature was kept for 3 hours, then the 90ml dichloromethane solution dissolved with chloroacetaldehyde (26.2g, 0.33mol) and chiral catalyst IIIb (8.4g, 0.033mol) And lithium perchlorate (10.7g, be dissolved in 89ml dichloromethane and 60mlTHF) solution is added dropwise in the reaction bottle, insulation reaction 1 hour, reaction solution is detected by online infrared, when wave number disappears at 1832 places peak, reaction is completed, reaction Add ethanol (20ml) to the solution to quench, stir for half an hour, then add water, stir for ha...

Embodiment 2

[0033] The synthetic method of L-carnitine is realized through the following steps:

[0034] 1) Preparation of β-chiral lactone

[0035] Under nitrogen protection, add dichloromethane (100ml) and acetyl chloride (39.3g, 0.5mol) to a 500ml double-layer reaction flask (equipped with nitrogen protection, stirring and dropping funnel), and cool the liquid to -50°C. DBU (76.1g, 0.5mol) was added dropwise, and the dropwise temperature was maintained for 3 hours, then the 90ml dichloromethane solution dissolved with chloroacetaldehyde (26.2g, 0.33mol) and chiral catalyst IIIc (7.3g, 0.033mol) And lithium perchlorate (10.7g, be dissolved in 89ml dichloromethane and 60mlTHF) solution is added dropwise in the reaction bottle, insulation reaction 1 hour, reaction solution is detected by online infrared, when wave number disappears at 1832 places peak, reaction is completed, reaction Add ethanol (20ml) to the solution, stir for half an hour, then add water, stir for half an hour, take it...

Embodiment 3

[0056] The synthetic method of L-carnitine is realized through the following steps:

[0057] 1) Preparation of β-chiral lactone

[0058] Under nitrogen protection, add dichloromethane (100ml) and acetyl chloride (39.3g, 0.5mol) to a 500ml double-layer reaction flask (equipped with nitrogen protection, stirring and dropping funnel), and cool the liquid to -50°C. DBU (76.1g, 0.5mol) was added dropwise, the drop was completed, and the temperature was kept for 3 hours, then 90ml of dichloromethane solution dissolved with chloroacetaldehyde (26.2g, 0.33mol) and chiral catalyst IIId (8.9g, 0.033mol) And the solution of lithium perchlorate (10.7g, being dissolved in 89ml dichloromethane and 60mlTHF) is added dropwise in reaction bottle, insulation reaction 1 hour, reaction solution is detected by online infrared, when wave number disappears at 1832 place peaks, reaction completes, Add ethanol (20ml) to the reaction solution, stir for half an hour, then add water, stir for half an ho...

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Abstract

The invention relates to an asymmetric synthesis method of L-carnitine. Acetyl chloride (II) generates ketene in situ at a low temperature under the catalysis of organic base, the ketene and 2-chloroacetaldehyde (I) are directly subjected to an asymmetric intermolecular [2+2] cycloaddition reaction without separation in the presence of Lewis acid and a chiral catalyst to obtain chiral lactone, andlactone (IV) is reacted with a trimethylamine solution to obtain L-carnitine with high enantioselectivity. The synthetic method is simple, the yield of asymmetric catalytic products is high, the enantioselectivity of lactone products is 95% or above, conditions are mild, operation is easy, the production cost is low, and the method can be used for industrial production.

Description

technical field [0001] The invention relates to an asymmetric synthesis method of L-carnitine, which belongs to the technical field of organic chemistry and also belongs to the technical field of medicinal chemistry. Background technique [0002] L-carnitine, abbreviated as VBT, exists in liver cells and plays an important role in the metabolism of animals. At present, L-carnitine has been used in the fields of medicine, health care and food, and has been stipulated as a legal multi-purpose nutritional agent by Switzerland, France, the United States and the World Health Organization. my country's food additive hygiene standard GB2760-1996 stipulates that L-carnitine tartrate is a food nutrition enhancer, which can be used in chewable tablets, drinking liquids, capsules, milk powder and milk drinks, etc., and can be used as one of the main components of weight loss nutritional food one. Therefore, it is of great significance to study its effective synthetic methods. [0003...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C227/06C07C229/22C07D305/12C07B53/00
CPCC07B53/00C07B2200/07C07C227/06C07D305/12C07C229/22
Inventor 申永存李天成邹颖梁夏瑜
Owner WUHAN UNIV OF TECH
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