Method for synthesizing and refining quinclorac

A technology of quinclorac and a synthesis method, applied in the field of pharmaceutical compounds, can solve the problems of complicated purification, low yield, poor product quality and the like, and achieve the effects of improving reaction yield, high yield and low cost

Inactive Publication Date: 2010-10-06
江苏绿利来股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of this invention is to seek a kind of method for the synthesis of quinclorac more ideally, to ove...

Method used

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  • Method for synthesizing and refining quinclorac
  • Method for synthesizing and refining quinclorac
  • Method for synthesizing and refining quinclorac

Examples

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Embodiment 1

[0026] First add 125mL of water in the reaction flask A, and add 560g of concentrated sulfuric acid (98%) dropwise under stirring. After the dropwise addition is completed, start to add 250g of 3-chloro-2-methylaniline, 2g of potassium iodide, and start to add dropwise of 185g of glycerin. Generally, the dropwise addition ends in 3 hours, and the dropping temperature is kept at 148-150°C. Keep warm for 2.5 hours, add 400 mL of water after the heat preservation, cool down to below 40°C, add petroleum ether (boiling range of 60-90°C) 1000ml. Start adding dilute lye (32%) dropwise. When the pH reaches 9-10, stop the dropwise addition, and separate the layers after standing for half an hour. The upper material is filtered, the filter cake is washed with 200ml of petroleum ether, the filtrates are combined, and distilled at atmospheric pressure until no fraction comes out. After the distillation was finished, 1000 ml of o-dichlorobenzene was added for use in the next step of chlor...

Embodiment 2

[0031] First add 125mL of water in the reaction flask A, and add 560g of concentrated sulfuric acid (98%) dropwise under stirring. After the dropwise addition is completed, start to add 250g of 3-chloro-2-methylaniline, 2g of potassium iodide, and start to add dropwise of 185g of glycerol. Generally, the dropwise addition ends in 3 hours, and the dropping temperature is kept at 148-150°C. Keep warm for 2.5 hours, add 400 mL of water after the heat preservation, cool down to below 40°C, add petroleum ether (boiling range of 60-90°C) 1000ml. Start adding dilute lye (32%) dropwise. When the pH reaches 9-10, stop the dropwise addition, and separate the layers after standing for half an hour. The upper material is filtered, the filter cake is washed with 200ml of petroleum ether, the filtrates are combined, and distilled at atmospheric pressure until no fraction comes out. After the distillation was finished, 1000 ml of o-dichlorobenzene was added for use in the next step of chlor...

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Abstract

The invention discloses a method for synthesizing and refining quinclorac. The synthesis method comprises the following steps of: preparing 7-chloro-8-methylquinoline by adopting m-chloro-o-toluidine and glycerol as raw materials; carrying out chlorination reaction on the 7-chloro-8-methylquinoline and chlorine to generate 3,7-dichloro-8-chloromethylquinoline; and finally oxidizing the 3,7-dichloro-8-chloromethylquinoline in concentrated sulfuric acid by concentrated nitric acid to obtain the quinclorac, wherein a chlorinating cocatalyst is added in the chlorination reaction, and an oxidizing cocatalyst is added in oxidation reaction. The synthesis method greatly improves reaction yield (larger than or equal to 65 percent) by using the chlorinating cocatalyst and the oxidizing cocatalyst and obtains a crude quinclorac product with higher content, and meanwhile, the quinclorac with high content (larger than or equal to 98 percent) is obtained by refining through using a one-step pressure kettle method. The process has the characteristics of simple and convenient operation, high yield, low cost, and the like.

Description

technical field [0001] The invention belongs to the field of pharmaceutical compounds, and in particular relates to a method for synthesizing quinclorac and a method for refining quinclorac refined products. Background technique [0002] The chemical name of quinclorac (Quinclorac) is 3,7-dichloro-8-quinoline carboxylic acid, and its structural formula is [0003] [0004] According to the report of DE3108873, using m-chloro-o-toluidine and glycerol as raw materials, the intermediate 7-chloro-8-methylquinoline was first prepared, and then chlorine gas was passed through dichlorobenzene to generate 3,7-dichloro-8-chloro Methyl quinoline, and then oxidized with concentrated nitric acid in concentrated sulfuric acid to obtain the target compound. The yield of this process is low, the total yield is only about 58%, and the content of quinclorac is low, generally only 78% to 82%. To obtain about 98% high content of quinclorac, it usually needs to be washed several times with...

Claims

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Application Information

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IPC IPC(8): C07D215/48
Inventor 许网保魏明阳臧伟新虞国新顾小宇周国平徐卫清
Owner 江苏绿利来股份有限公司
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