Method for preparing chlorzoxazone

A technology of chlorzoxazone and nitrophenol, which is applied in the field of chemical drug synthesis, can solve the problems of difficult industrial production, easy to be oxidized and discolored, and many solid wastes, so as to avoid oxidative deterioration, reduce residence time, and increase overall yield Effect

Inactive Publication Date: 2016-11-30
XENOAH PHARMA INC
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0009] The advantage of this method is that the raw materials are easy to get, and the reaction conditions are mild, but the use of the reducing agent sodium disulfide will pollute the environment, and produce a considerable amount of solid waste, and the intermediate 2-amino-4-chlorophenol is easily oxidized and discolored , not easy to store, which makes it difficult for industrial production

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  • Method for preparing chlorzoxazone
  • Method for preparing chlorzoxazone
  • Method for preparing chlorzoxazone

Examples

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Embodiment 1

[0039] Example 1: Preparation of Chlorzoxazone

[0040] Add 50-100mL methanol, 1.0g Raney / Ni, 10g 4-chloro-2-nitrophenol into a 350mL autoclave, seal the reactor, start stirring, replace the air in the reaction system with hydrogen, and keep the hydrogen pressure 0.1~ 0.2MPa, room temperature reaction, chromatographic tracking reaction.

[0041] After the reaction, under the protection of nitrogen, filter to remove Raney / Ni. Add 10-30 mL of water to the filtrate, and distill off methanol. Add 5-7 mL of 36% concentrated hydrochloric acid and 0.5 g of activated carbon to the residual liquid, raise the temperature to 50°C, stir for half an hour, filter, and wash with water.

[0042] Add 8.6g of urea to the filtrate, heat to reflux for 1 hour, add concentrated hydrochloric acid to control the reaction liquid to be acidic, and continue to reflux for three hours. During this process, add concentrated hydrochloric acid to ensure the acidity of the reaction liquid Afterwards, reflux the r...

Embodiment 2

[0044] Example 2: Preparation of Chlorzoxazone

[0045] Add 200-400mL methanol, 4.0g Raney / Ni, 40g 4-chloro-2-nitrophenol to a 2L autoclave, seal the reactor, start stirring, replace the air in the reaction system with hydrogen, and keep the hydrogen pressure 0.1~ 0.2MPa, room temperature reaction. After the reaction is complete, protect with nitrogen and filter to remove Raney / Ni. 40-120 mL of water was added to the filtrate, and methanol was distilled off. Add 20-30 mL of 36% concentrated hydrochloric acid and 2 g of activated carbon to the residual liquid, raise the temperature to 50°C, stir for half an hour, filter, and wash with water. Add 34.4g of urea to the filtrate, heat to reflux for 1 hour, add concentrated hydrochloric acid to control the reaction liquid to be acidic, and continue to reflux for three hours. During this process, continuously add concentrated hydrochloric acid to ensure the acidity of the reaction liquid Afterwards, reflux the reaction overnight. Af...

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Abstract

The invention provides a method for preparing chlorzoxazone. A synthetic method of first performing hydrolysis and then performing hydrogenation reduction and cyclization one-pot reaction and generating chlorzoxazone through two-step reaction in total is adopted. A hydrolyzate is obtained mainly by heating and hydrolyzing raw material 2,5-dichloronitrobenzene in super-saline water solution. After filtration and drying, 4-chloro-2-nitrophenol with the purity larger than 99% can be obtained. The whole synthetic route has two steps in total, the second step integrates reduction reaction and cyclization reaction, and not only is the overall yield effectively improved, but also the reaction period is shortened. The retention time of 2-amino-4-chlorophenol is reduced, and a separated compound is protected from oxidative deterioration.

Description

Technical field [0001] The invention relates to a preparation method of a pharmaceutical compound Chlorzoxazone (Chlorzoxazone), which belongs to the field of chemical drug synthesis. Background technique [0002] Chlorzoxazone is a central skeletal muscle relaxant used to treat various skeletal muscle disorders, such as various acute and chronic soft tissue (muscles, ligaments) sprains, contusions, muscle soreness after exercise, muscles, ligaments, Fascial sprains, etc., have a certain effect on muscle spasms caused by central neuropathy, chronic fasciitis, and children's mental retardation. [0003] Chinese patent CN1560040A discloses a synthetic method of chlorzoxazone. The main synthetic route is as follows: [0004] [0005] This method uses 2,5-dichloronitrobenzene as the starting material, and undergoes three steps of reduction, hydrolysis and cyclization. During the reduction reaction, LiAlH 4 Or Raney / Ni as a reducing agent, use water, alcohol, ether or tetrahydrofuran as ...

Claims

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Application Information

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IPC IPC(8): C07D263/58
CPCC07D263/58
Inventor 王亚农戈平张鲁岩
Owner XENOAH PHARMA INC
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