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Synthesis method of medicinal calcium D,L-2-hydroxyl-4-(methylthio)butyrate

A technology of calcium methylthiobutyrate and methylthiobutyric acid, applied in the field of medicinal D, can solve the problems of difficult drying of products, low product yield, harsh conditions, etc., and achieves environmentally friendly, easy purification, and mild process. Effect

Inactive Publication Date: 2011-06-01
ZHEJIANG NHU CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Problems in this method: 1, the reaction is difficult to carry out thoroughly; 2, because D, L-2-hydroxyl-4-methylthiobutyric acid has 23-24% polymers, some of these polymers are lactone and exists in the form of acid anhydrides, and these polymers cannot be combined with solid Ca(OH) 2 Or CaO reacts, and finally adsorbs on the surface of the product, causing the product to be difficult to dry and affecting the quality of the product
The steps of this method are cumbersome, racemic D, L-2-hydroxy-4-methylthiobutyrate has a high boiling point, high temperature and high vacuum are required for rectification and purification, the conditions are harsh, and the product yield is low, so it is not suitable for industrial production

Method used

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  • Synthesis method of medicinal calcium D,L-2-hydroxyl-4-(methylthio)butyrate
  • Synthesis method of medicinal calcium D,L-2-hydroxyl-4-(methylthio)butyrate

Examples

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Embodiment 1

[0027] Embodiment 1: D, the preparation of L-2-hydroxyl-4-methylthiobutyramide

[0028] In a 500mL four-necked flask with mechanical stirring and a thermometer, drop into a content of 85% D, 176.5g (1.0mol) of L-2-hydroxyl-4-methylthiobutyric acid, stir, and cool in an ice-water bath at 20 102.0 g (1.2 mol) of 20% ammonia water was added dropwise at -30°C. After the dropwise addition was completed, the mixture was stirred at room temperature for 0.5 hour, then heated to 50-60°C and stirred for 2 hours. Evaporate water under reduced pressure and vacuum, keep the vacuum degree of 200Pa and raise the temperature, gradually raise the temperature to 150°C, dehydration reaction at 150-160°C for 6 hours, and cool to room temperature. Add 500 mL of dichloromethane for extraction, add 5 g of activated carbon to the dichloromethane layer, decolorize and filter. The dichloromethane extract was evaporated to dryness and recrystallized with 200 mL of n-hexane to obtain 121.0 g of D,L-2-hy...

Embodiment 2

[0029] Embodiment 2: D, the preparation of L-2-hydroxyl-4-methylthiobutyramide

[0030] In a 500mL four-necked flask with mechanical stirring and a thermometer, drop into a content of 85% D, 176.5g (1.0mol) of L-2-hydroxyl-4-methylthiobutyric acid, stir, and cool in an ice-water bath at 20 102.0 g (1.2 mol) of 20% ammonia water was added dropwise at -30°C. After the dropwise addition was completed, the mixture was stirred at room temperature for 0.5 hour, then heated to 50-60°C and stirred for 2 hours. Evaporate water under reduced pressure and vacuum, keep the vacuum degree of 200Pa and raise the temperature, gradually raise the temperature to 150°C, dehydrate at 170-180°C for 4 hours, and cool to room temperature. Add 500 mL of dichloromethane for extraction, add 5 g of activated carbon to the dichloromethane layer, decolorize and filter. The dichloromethane extract was evaporated to dryness, and recrystallized with 200 mL of n-hexane to obtain 129.0 g of D,L-2-hydroxy-4-me...

Embodiment 3

[0031] Embodiment 3: D, the preparation of L-2-hydroxyl-4-methylthiobutyrate calcium

[0032] In a 500mL four-neck flask with mechanical stirring and a thermometer, put 98.5% D, L-2-hydroxyl-4-methylthiobutyramide 75.6g (0.5mol), and add 30% sodium hydroxide 80.0g (0.6mol), heated up to 100-105°C and stirred for 2 hours, it was detected that the conversion of D,L-2-hydroxy-4-methylthiobutyramide was completed, the temperature was lowered to 60°C, and 30 111.0 g (0.3 mol) of aqueous calcium chloride solution, after the dropwise addition, continue to stir and react at 50-60° C. for 1 hour, and cool to room temperature. Filter, wash with water, and recrystallize the filter cake with 20% aqueous ethanol to obtain 70.1 g of calcium D,L-2-hydroxy-4-methylthiobutyrate, with a content of 99.3% and a yield of 82.2%.

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Abstract

The invention discloses a synthesis method of medicinal calcium D,L-2-hydroxyl-4-(methylthio)butyrate. By adopting the existing methods, the product has more impurities and poor quality; and some methods have harsh conditions and low product yield and are not suitable for industrial production. The synthesis method comprises the following steps: using feed grade D,L-2-hydroxyl-4-methylthiobutyricacid of which the content is less than 90% or D,L-2-hydroxyl-4-methylthiobutyric acid of which the content is 75-90% as a starting raw material to react with ammonia and generate an ammonium salt, performing dehydration to obtain D,L-2-hydroxyl-4-methylthiobutyramide, extracting, concentrating, crystallizing and purifying to obtain D,L-2-hydroxyl-4-methylthiobutyramide of which the content is more than 98.5%; and hydrolyzing to generate D,L-2-hydroxyl-4-methylthiobutyrate, and performing the salt forming reaction with CaX2 to generate calcium D,L-2-hydroxyl-4-(methylthio)butyrate. The synthesis method in the invention has mild process conditions, less side reactions and high yield.

Description

technical field [0001] The invention relates to the field of fine chemical industry, in particular to a method for synthesizing medicinal D, L-2-hydroxy-4-methylthiobutyrate calcium. Background technique [0002] D, Calcium L-2-hydroxy-4-methylthiobutyrate is the calcium salt of the racemic hydroxyl analog of aminomethionine, which is widely used in feed additives. In addition, studies have demonstrated that calcium D,L-2-hydroxy-4-methylthiobutyrate has medicinal uses as an alternative or supplement to dialysis therapy in the treatment of renal failure. [0003] The structural formula of D, L-2-hydroxy-4-methylthiobutyrate calcium is as follows: [0004] [0005] US3272860A uses alkyl glycol monoether as a solvent, adding Ca(OH) during the hydrolysis reaction of 2-hydroxyl-4-methylthiobutyronitrile 2 Or CaO, D, L-calcium 2-hydroxy-4-methylthiobutyrate was prepared with a content of 98%. [0006] CN1493560A takes D, L-2-hydroxyl-4-methylthiobutyric acid as raw material...

Claims

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Application Information

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IPC IPC(8): C07C323/52C07C319/20
Inventor 鲁国彬钱洪胜周茜陈洪光吕文庆
Owner ZHEJIANG NHU CO LTD
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