Method for synthesizing flunixin meglumine

Abstract

The invention provides a method for synthesizing flunixin meglumine. According to the method, reaction is carried out in a manner that 2-chloronicotinic acid and 2-methyl-3-trifluoromethylaniline serve as raw materials, water serves as a solvent and cupric oxide and para-toluenesulfonic acid serve as catalysts. According to the method, on the premise that the condition that para-toluenesulfonic acid serves as a catalyst is reported in the existing literature, cupric oxide is added, so that the catalysis efficiency is increased greatly, the reaction can be carried out efficiently, the reaction time is shortened, and the yield is increased; obtained flunixin and meglumine are salified in an acetonitrile solvent and are recrystallized, so as to obtain flunixin meglumine, and the total yield is about 90%; through synthesizing flunixin meglumine by the method, the operation is convenient and simple, and the requirements for equipment are low, so that the method is applicable to industrial large-scale production.

Description

Technical field:

[0001] The invention relates to a method for synthesizing flunixin meglumine, which belongs to the field of veterinary drug synthesis. Background of the invention:

[0002] Flunixin meglumine is an anti-inflammatory and analgesic drug for veterinary use. It has antipyretic, anti-inflammatory and analgesic effects. It can significantly improve clinical symptoms and enhance the activity of antibiotics when used alone or in combination with antibiotics. In veterinary medicine, it is often used to relieve horses' visceral colic, pain caused by muscle and bone disorders, and anti-inflammation; to control acute inflammation caused by various diseases and infections in cattle, such as laminitis, arthritis, etc., and can also be used for females. Adjuvant treatment of porcine mastitis, metritis and agalactia syndrome:

[0003]

[0004] At present, the preparation method of flunixin meglumine reported in the literature is mainly divided into two steps, the first ...

Examples

Embodiment 1

[0021] Preparation of flunixin:

[0022] (1) Add 500g of purified water, 55.1g of 2-chloronicotinic acid, 122.6g of 2-methyl-3-trifluoromethylaniline, 0.6g of p-toluenesulfonic acid, and 0.28g of copper oxide into a 1000mL reaction flask equipped with a reflux tube , stirred and heated to reflux, and kept warm for 4 hours.

[0023] (2) The reaction solution is cooled to below 50°C, and 25% potassium hydroxide solution is added dropwise to the reaction solution to adjust the pH value to 10.0 to 11.0. After the adjustment, continue stirring and cool down to below 20°C, fully stir for 1 hour, and suction filter. The filter cake is mainly excess 2-methyl-3-trifluoromethylaniline, which can be recycled for further use.

[0024] (3) Add 30% sulfuric acid dropwise to the filtrate to adjust the pH value to 5.0-6.0, fully stir and crystallize for 1 hour, filter with suction, stir and wash the filter cake with 300 g of purified water for 30 minutes, filter, and dry. 94.5 g of the prod...

Embodiment 2

[0029] Preparation of Flunixin:

[0030] (1) Add 500g of purified water, 55.1g of 2-chloronicotinic acid, 122.6g of 2-methyl-3-trifluoromethylaniline, 3.0g of p-toluenesulfonic acid, and 1.4g of copper oxide into a 1000mL reaction flask equipped with a reflux tube , stirred and heated to reflux, and kept for 2.5 hours.

[0031] (2) The reaction solution is cooled to below 50°C, and 25% potassium hydroxide solution is added dropwise to the reaction solution to adjust the pH value to 10.0 to 11.0. After the adjustment, continue stirring and cool down to below 20°C, fully stir for 1 hour, and suction filter. The filter cake is mainly excess 2-methyl-3-trifluoromethylaniline, which can be recycled for further use.

[0032] (3) Add 30% sulfuric acid dropwise to the filtrate to adjust the pH value to 5.0-6.0, fully stir and crystallize for 1 hour, filter with suction, stir and wash the filter cake with 300 g of purified water for 30 minutes, filter, and dry. 98.5 g of the product ...

Embodiment 3

[0037] (1) Add 1000g purified water, 110.2g 2-chloronicotinic acid, 245.2g 2-methyl-3-trifluoromethylaniline, 12.0g p-toluenesulfonic acid, 5.6g copper oxide to a 2000mL reaction flask equipped with a reflux tube , stirred and heated to reflux, and kept warm for 2 hours.

[0038] (2) The reaction solution is cooled to below 50°C, and 25% potassium hydroxide solution is added dropwise to the reaction solution to adjust the pH value to 10.0 to 11.0. After the adjustment, continue stirring and cool down to below 20°C, fully stir for 1 hour, and suction filter. The filter cake is mainly excess 2-methyl-3-trifluoromethylaniline, which can be recycled for further use.

[0039] (3) Add 30% sulfuric acid dropwise to the filtrate to adjust the pH value to 5.0-6.0, fully stir and crystallize for 1 hour, filter with suction, stir and wash the filter cake with 300 g of purified water for 30 minutes, filter, and dry. 196.4 g of the product was obtained, the yield was 94.5%, and the HPLC p...

Technical field:

[0001] The invention relates to a method for synthesizing flunixin meglumine, which belongs to the field of veterinary drug synthesis. Background of the invention:

[0002] Flunixin meglumine is an anti-inflammatory and analgesic drug for veterinary use. It has antipyretic, anti-inflammatory and analgesic effects. It can significantly improve clinical symptoms and enhance the activity of antibiotics when used alone or in combination with antibiotics. In veterinary medicine, it is often used to relieve horses' visceral colic, pain caused by muscle and bone disorders, and anti-inflammation; to control acute inflammation caused by various diseases and infections in cattle, such as laminitis, arthritis, etc., and can also be used for females. Adjuvant treatment of porcine mastitis, metritis and agalactia syndrome:

[0003]

[0004] At present, the preparation method of flunixin meglumine reported in the literature is mainly divided into two steps, the first ...

Examples

Embodiment 1

[0021] Preparation of flunixin:

[0022] (1) Add 500g of purified water, 55.1g of 2-chloronicotinic acid, 122.6g of 2-methyl-3-trifluoromethylaniline, 0.6g of p-toluenesulfonic acid, and 0.28g of copper oxide into a 1000mL reaction flask equipped with a reflux tube , stirred and heated to reflux, and kept warm for 4 hours.

[0023] (2) The reaction solution is cooled to below 50°C, and 25% potassium hydroxide solution is added dropwise to the reaction solution to adjust the pH value to 10.0 to 11.0. After the adjustment, continue stirring and cool down to below 20°C, fully stir for 1 hour, and suction filter. The filter cake is mainly excess 2-methyl-3-trifluoromethylaniline, which can be recycled for further use.

[0024] (3) Add 30% sulfuric acid dropwise to the filtrate to adjust the pH value to 5.0-6.0, fully stir and crystallize for 1 hour, filter with suction, stir and wash the filter cake with 300 g of purified water for 30 minutes, filter, and dry. 94.5 g of the prod...

Embodiment 2

[0029] Preparation of Flunixin:

[0030] (1) Add 500g of purified water, 55.1g of 2-chloronicotinic acid, 122.6g of 2-methyl-3-trifluoromethylaniline, 3.0g of p-toluenesulfonic acid, and 1.4g of copper oxide into a 1000mL reaction flask equipped with a reflux tube , stirred and heated to reflux, and kept for 2.5 hours.

[0031] (2) The reaction solution is cooled to below 50°C, and 25% potassium hydroxide solution is added dropwise to the reaction solution to adjust the pH value to 10.0 to 11.0. After the adjustment, continue stirring and cool down to below 20°C, fully stir for 1 hour, and suction filter. The filter cake is mainly excess 2-methyl-3-trifluoromethylaniline, which can be recycled for further use.

[0032] (3) Add 30% sulfuric acid dropwise to the filtrate to adjust the pH value to 5.0-6.0, fully stir and crystallize for 1 hour, filter with suction, stir and wash the filter cake with 300 g of purified water for 30 minutes, filter, and dry. 98.5 g of the product ...

Embodiment 3

[0037] (1) Add 1000g purified water, 110.2g 2-chloronicotinic acid, 245.2g 2-methyl-3-trifluoromethylaniline, 12.0g p-toluenesulfonic acid, 5.6g copper oxide to a 2000mL reaction flask equipped with a reflux tube , stirred and heated to reflux, and kept warm for 2 hours.

[0038] (2) The reaction solution is cooled to below 50°C, and 25% potassium hydroxide solution is added dropwise to the reaction solution to adjust the pH value to 10.0 to 11.0. After the adjustment, continue stirring and cool down to below 20°C, fully stir for 1 hour, and suction filter. The filter cake is mainly excess 2-methyl-3-trifluoromethylaniline, which can be recycled for further use.

[0039] (3) Add 30% sulfuric acid dropwise to the filtrate to adjust the pH value to 5.0-6.0, fully stir and crystallize for 1 hour, filter with suction, stir and wash the filter cake with 300 g of purified water for 30 minutes, filter, and dry. 196.4 g of the product was obtained, the yield was 94.5%, and the HPLC p...

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