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Production method of N-acetyl-L-cysteine

A technology of cysteine ​​and production method, applied in sulfide preparation, organic chemistry and other directions, can solve the problems of affecting product quality, increasing product impurity content and production cost, and high content, and achieves the effect of reducing impurity content and production cost

Active Publication Date: 2015-08-19
WUHAN GRAND HOYO
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] CN 103102295A discloses a production method of N-acetyl-L-cysteine. The method is to combine L-cysteine ​​hydrochloride and acetic anhydride under the conditions of pressure of 0.4Mpa and temperature of 125-135°C. The method has the following disadvantages: 1) reacts under high temperature and high pressure conditions, resulting in high content of reaction by-product N-acetyl-D-cysteine ​​and other related substances, which seriously affects product quality; 2) acyl The reaction needs to add excessive acetic anhydride (the weight ratio of cysteine ​​hydrochloride and acetic anhydride is about 1: 3.3), which will easily cause the racemization of the reaction substrate, increase the impurity content and production cost of the product

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0015] A production method of N-acetyl-L-cysteine, comprising the following steps:

[0016] 1) Add 1200Kg weight content to the reactor and be the aqueous solution of 50% L-cysteine ​​hydrochloride monohydrate (equivalent to 600kg of L-cysteine ​​hydrochloride monohydrate), then add 20% Sodium hydroxide solution, adjust the pH value to 10, start to slowly add acetic anhydride and carry out acylation reaction under normal pressure, when the temperature of the reaction solution rises to 60°C, circulate the reaction solution through the heat exchange device to make the reaction The temperature of the reaction solution in the kettle was maintained at 60°C until the acetic anhydride was added (a total of 300Kg was added, which took 1.5 hours), and then the insulation was continued for 1 hour;

[0017] 2) adding hydrochloric acid to the reaction solution, adjusting the pH to 2, concentrating in vacuo, cooling to crystallize, and centrifuging to collect the crystals to obtain crude N...

Embodiment 2

[0020] A production method of N-acetyl-L-cysteine, comprising the following steps:

[0021] 1) Adding 1090Kg weight content in the reactor is an aqueous solution of 55% L-cysteine ​​hydrochloride monohydrate (equivalent to 600kg of cysteine ​​hydrochloride monohydrate), then adding sodium hydroxide solution, Adjust the pH value to 8, start to slowly add acetic anhydride and carry out the acylation reaction under normal pressure, when the temperature of the reaction solution rises to 20°C, circulate the reaction solution through the heat exchange device to make the reaction solution in the reactor The temperature was kept at 50°C until the acetic anhydride was added (a total of 300Kg was added, which took 1.5 hours), and then kept for 2 hours;

[0022] 2) adding hydrochloric acid to the reaction solution, adjusting the pH to 2.5, concentrating in vacuo, cooling to crystallize, and centrifuging to collect the crystals to obtain crude N-acetyl-L-cysteine;

[0023] 3) Dissolve th...

Embodiment 3

[0025] A production method of N-acetyl-L-cysteine, comprising the following steps:

[0026] 1) Adding 1000Kg weight content to the reactor is an aqueous solution of 60% L-cysteine ​​hydrochloride monohydrate (equivalent to 600kg of cysteine ​​hydrochloride monohydrate), then adding sodium hydroxide solution, Adjust the pH value to 11, start slowly adding acetic anhydride and carry out the acylation reaction under normal pressure, when the temperature of the reaction solution rises to 90°C, circulate the reaction solution through the heat exchange device to make the reaction solution in the reactor The temperature was kept at 70°C until the acetic anhydride was added (a total of 300Kg was added, which took 1 hour), and then kept for 0.5 hours;

[0027] 2) adding hydrochloric acid to the reaction solution, adjusting the pH to 2, concentrating in vacuo, cooling to crystallize, and centrifuging to collect the crystals to obtain crude N-acetyl-L-cysteine;

[0028] 3) Dissolve the ...

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Abstract

The invention discloses a production method of N-acetyl-L-cysteine. According to the production method disclosed by the invention, the temperature of acylation reaction is controlled at about 60 DEG C. Under the condition of the temperature, not only is reaction on L-cysteine hydrochloride and acetic anhydride more fully, but also the content of the byproduct N-acetyl-D-cysteine in the product is very low. In addition, according to the preparation method disclosed by the invention, the reaction conditions are strictly controlled, such as concentration of an L-cysteine hydrochloride solution, pH, temperature, pressure of the reaction and the adding manner of acetic anhydride, so that reaction on L-cysteine hydrochloride and acetic anhydride is more fully. Excessive acetic anhydride is not needed for acylation reaction so that the impurity content of the product is reduced and the production cost of the product is lowered.

Description

technical field [0001] The invention belongs to the field of pharmacy, and in particular relates to a production method of N-acetyl-L-cysteine. Background technique [0002] Acetylcysteine ​​is an amino acid drug and an expectorant, its chemical name is N-acetyl-L-cysteine, its molecular formula is C5H9NO3S, and the chemical name of its enantiomer is N-acetyl -D-cysteine. [0003] CN 103102295A discloses a production method of N-acetyl-L-cysteine. The method is to combine L-cysteine ​​hydrochloride and acetic anhydride under the conditions of pressure of 0.4Mpa and temperature of 125-135°C. The method has the following disadvantages: 1) reacts under high temperature and high pressure conditions, resulting in high content of reaction by-product N-acetyl-D-cysteine ​​and other related substances, which seriously affects product quality; 2) acyl The reaction needs to add excessive acetic anhydride (the weight ratio of cysteine ​​hydrochloride and acetic anhydride is about 1: ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C323/59C07C319/20
Inventor 王君英
Owner WUHAN GRAND HOYO
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