Preparation process of chlorazol thazone

A technology for chlorzoxazone and dichloronitrobenzene is applied in the field of preparation of the compound chlorzoxazone, which can solve the problems of unsuitable storage, large human toxicity, difficult application and the like, and achieves the effects of reducing side reactions and improving purity

Active Publication Date: 2006-01-11
LUNAN PHARMA GROUP CORPORATION
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

[0015] The advantage of this method is that the starting materials are easy to obtain and the price is low. The medium solvent and raw materials used in the whole route are also easy to obtain and are relatively cheap. However, NaNO2 is highly toxic and harmful to the human body, and the whole route has four steps. The route is longer, the cost is slightly higher, and the intermediate 2-amino-4-chlorophenol is easily oxidized and discolored, so it is not suitable for storage, and the problem that the obtained chlorzoxazone (1) is easily discolored after being placed for a long time is not solved.
All of these make it difficult to apply in the field of industrial production and medicine

Method used

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  • Preparation process of chlorazol thazone
  • Preparation process of chlorazol thazone
  • Preparation process of chlorazol thazone

Examples

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example 1

[0028] Example one: the preparation of 2,5-dichloroaniline (3)

[0029] Add 48 grams of compound (2) to 200 milliliters of ethanol, 5 grams of Ranney / Ni, and feed hydrogen under 3Mpa pressure. After 5 hours, the reaction is complete, filter to remove the catalyst, and concentrate to dryness to obtain compound (3), mp=51° C. , yield 91%.

example 2

[0030] Example two: the preparation of 2-amino-4-chlorophenol (4)

[0031] Put 260 grams of compound (3), 650 milliliters of water, and 330 grams of 30% sodium hydroxide into a 2000 milliliter reaction bottle, stir, heat up to 85 ° C, react for 2 hours, cool down to room temperature, add a saturated solution of baking soda to adjust the pH value of the solution Between 8-9, the crude product of compound (4) was obtained by filtration, mp=140°C, yield 86%.

example 3

[0032] Example three: the preparation of chlorzoxazone (1)

[0033] Add 100 grams of compound (4), 180 grams of urea, and 150 grams of 30% hydrochloric acid into a 1000 milliliter reaction flask, heat up to reflux for one hour, add 110 grams of 30% hydrochloric acid and continue the reflux reaction for 30 minutes, then add 100 grams of 30% hydrochloric acid to continue The reaction was refluxed until the reaction was complete (TLC detection), the temperature was lowered to 40° C., and the off-white crude chlorzoxazone was obtained by filtration. Refined with 450 g of 50% ethanol to obtain fine chlorzoxazone (1), mp=191-192°C, yield 85%, and purity greater than 99.5%.

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Abstract

The invention relates to a method of preparing oral potent muscle relaxant-chlorzoxaone, including the steps: firstly adopting 2, 5-dichloronitrobenzene as raw material and Ranney / Ni as catalyst, making reduction reaction at pressure 3MPa to generate 2, 5-dichlorsaniline, which is hydrolyzed by sodium / potassium hydroxide at temperature 85 deg.C to generate 2-amido-4-chlorophenol, which directly makes cyclization with carbamide by HCl without refining to generate crude chlorzoxaone, and finally obtaining pure chlorzoxaone by refining with 50% alcohol.

Description

technical field [0001] The invention relates to a preparation method of compound chlorzoxazone (5-chloro-2-benzoxazolone), belonging to the fields of chemical industry and chemical medicine. Background technique [0002] Chlorzoxazon (Chlorzoxazon) is the general name of 5-chloro-2-benzoxazolone, and its structural formula is: [0003] [0004] Chlorzoxazone is a powerful oral muscle relaxant developed by McNeil Pharmaceuticals in the United States and launched in the mid-1960s. It is clinically used to treat low back pain, neuralgia, rheumatoid arthritis, acute and chronic For soft tissue contusions, sprains, and muscle spasms and stiffness caused by spinal diseases, the total effective rate is as high as 98.59%. It also has a certain effect on children's brain dysfunction. [0005] There are mainly five synthetic methods of chlorzoxazone reported abroad: [0006] [0007] [0008] [0009] [0010] [0011] The above synthetic methods have their own ch...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D263/58
Inventor 赵志全
Owner LUNAN PHARMA GROUP CORPORATION
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