A kind of preparation method of s-(carboxymethyl)-cysteine

A technology of cysteine ​​and carboxymethyl, which is applied in the field of preparation of S-cysteine, can solve the problems of reduced purity of the final product, safety problems, and low efficiency, and achieve the goal of increasing product yield and reducing drying The effect of duration

Active Publication Date: 2020-08-21
北京云鹏鹏程医药科技有限公司
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Use liquid ammonia and ammonium bicarbonate to adjust the pH. The liquid ammonia is stored in a pressure tank, which has safety problems, and the amount of addition is difficult to control. At the same time, the ammonium salt and chloride in the final product are easy to exceed the standard.
[0005] In addition, the raw material L-cysteine ​​hydrochloride is easily oxidized to cystine under neutral or strong alkaline conditions, resulting in a decrease in the purity of the final product. processing it is less efficient

Method used

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  • A kind of preparation method of s-(carboxymethyl)-cysteine
  • A kind of preparation method of s-(carboxymethyl)-cysteine
  • A kind of preparation method of s-(carboxymethyl)-cysteine

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preparation example Construction

[0030] Such as Figure 1-6 Shown, the preparation method of a kind of S-(carboxymethyl)-cysteine ​​of the present invention comprises the steps:

[0031] a. Before the reaction of L-cysteine ​​hydrochloride, a reducing agent is used for pretreatment, and the reducing agent is iron powder;

[0032] b. Add the aqueous solution of chloroacetic acid in the system, along with the dropwise addition of lye, the reaction continues to the positive reaction direction, and the reaction is completed when the pH of the system is 6.0-12.0;

[0033] c. Add acid dropwise to near the isoelectric point of the product. The acid added dropwise is dilute hydrochloric acid, dilute sulfuric acid or glacial acetic acid; the crystallization temperature is -10 to 30°C, the crystallization time is more than 10 hours, and the crude product is obtained by low temperature crystallization ;

[0034] d. Soluble in lye at room temperature, the alkali is NaOH, KOH, Na 2 CO 3 , NaHCO3, ammonia water or trie...

Embodiment 1

[0042] Add 100.0g of L-cysteine ​​hydrochloride mixture (L-cysteine ​​hydrochloride content 50.2%, L-cystine content 49.0%) and 500mL purified water into 1 L reaction kettle, open at room temperature Stir, add 30.0g of iron powder, raise the temperature to 60°C, react for 30min after reaching the temperature, and then lower the temperature. When the temperature of the reactor reaches 30-40°C, add 66.4g of chloroacetic acid to the reactor and start to add sodium hydroxide solution dropwise. The reaction temperature does not exceed 60°C. When the monitored pH is 7.0-8.0, stop adding the sodium hydroxide solution dropwise, and keep the temperature at 60°C for 30min. After cooling down to room temperature, dilute sulfuric acid was added dropwise to control the temperature of the reaction solution below 30°C. When the pH of the system is about 2.5-3.0, the end point is reached, the temperature is lowered to -5 to 10°C and kept for 16 hours, the filter cake is rinsed with 30g of wa...

Embodiment 2

[0045] Add 100.0g of L-cysteine ​​hydrochloride monohydrate (L-cysteine ​​hydrochloride content 99.5%) and 300mL of purified water into a 1 L reaction kettle, start stirring, dissolve at room temperature, then add Iron powder 5.0g, heat up to 60°C, react for 30 minutes after reaching the temperature, then lower the temperature, when the temperature of the reactor reaches 30-40°C, add 56.5g of chloroacetic acid to the reactor and start adding sodium bicarbonate solution dropwise to control the reaction temperature. over 60°C. When the monitored pH is 7.0-8.0, stop adding the sodium bicarbonate solution dropwise, and keep the temperature at 60°C for 30min. When the temperature is lowered to 15-30°C, dilute sulfuric acid is added dropwise to control the temperature of the reaction solution below 30°C. When the pH of the system is about 2.5-3.0, the end point is reached, the temperature is lowered to -5 to 0°C and kept for 12 hours, the filter cake is rinsed with 30g of water, fi...

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Abstract

The invention belongs to the technical field of compound preparation and particularly relates to a preparation method of high-purity S-(carboxymethyl)-cysteine. First, L-cysteine hydrochloride is pretreated by a reducing agent before reaction, an aqueous solution of chloroacetic acid is added into the system, and the reaction is continuously carried out in the positive reaction direction with dropping addition of an alkaline solution until the reaction is finished when the pH value of the system is 6.0-12.0, an acid is dropwise added to the vicinity of an isoelectric point of the product, andcrystallization is carried out at low temperature to obtain a crude product; the crude product is dissolved in the alkaline solution at room temperature, an organic acid is dropwise added until a product precipitates when the pH value is about 2.8, the precipitated product is put into a tray, the tray is put on the water surface and is pretreated by heating, moisture in a filter cake is heated until small bubbles are generated in the pretreatment process, and the generated bubbles counter-react with the filter cake, so that substances in the moisture in the filter cake further generate a precipitated product through the vibration effect of the bubbles, and finally the pretreated precipitated product is put into an all-in-one machine to obtain the product.

Description

technical field [0001] The invention belongs to the technical field of compound preparation, in particular to a preparation method of S-(carboxymethyl)-cysteine. Background technique [0002] S-(carboxymethyl)-cysteine, another name carbocisteine, white crystalline powder; odorless, slightly soluble in hot water, insoluble in ethanol or acetone; easily soluble in acid or alkali solution. Carbocisteine ​​is a mucus thinner, which mainly affects the secretion of bronchial glands at the cellular level. It can break the disulfide bond of mucin in mucus, increase the secretion of low-viscosity sialomucin, and increase the secretion of high-viscosity rock mucin. The production of algal mucin is reduced, which reduces the viscosity of sputum and facilitates the discharge of sputum. [0003] The sites of action of carbocisteine ​​are the epithelial mucosa and mucous glands of the airway, nasal cavity, sinuses and middle ear. The epithelial mucous membranes of the respiratory tract...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C319/14C07C323/58
CPCC07B2200/07C07C319/14C07C323/58
Inventor 刘显海
Owner 北京云鹏鹏程医药科技有限公司
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