Production method of mefenamic acid

Abstract

The invention discloses a production method of mefenamic acid, which comprises the following steps of: (1) adding water and o-chlorobenzoic acid into a reaction kettle, evenly mixing, and dropwise adding a sodium hydroxide solution while stirring, thereby obtaining a mixed solution; (2) adding solid sodium bicarbonate into the mixed solution in the step (1), adding chalcanthite, 2,3-dimethylaniline and cetyl trimethyl ammonium chloride, and carrying out reflux reaction; (3) after the reflux reaction in the step (2) is finished, dropwise adding hydrochloric acid, and filtering to obtain the crude product; (4) washing the crude product in the step (3) with water, filtering, and drying under reduced pressure to obtain the crude product; and (5) adding dimethyl formamide and water to dissolvethe crude product in the step (4), adding activated carbon to carry out reflux decolorization, filtering, cooling to room temperature to crystallize, filtering, recrystallizing, washing with water after the filtration for the last recrystallization, and drying under reduced pressure to obtain the fine mefenamic acid product. The invention can lower the production cost, easily implement industrialproduction, and overcome the defects in the prior art.

Description

technical field [0001] The invention relates to medicines, in particular to a production method of mefenamic acid. Background technique [0002] Mefenamic acid itself is an anti-inflammatory drug, and it is also an intermediate for preparing acridine antimalarial drugs and anticancer drugs. Because mefenamic acid has broad application prospects, all countries have been expanding production scale in recent years. Although several production methods of mefenamic acid are disclosed in the art, there are some deficiencies: for example, CN101475505A uses dimethylformamide, toluene, etc. as reaction solvents and quaternary ammonium salts as phase transfer catalysts to prepare mefenamic acid. The production cost of this method is higher, and environmental pollution is heavier, and the difficulty of processing pollution is bigger; The deficiency of CN101704761A production method is, owing to be to react in oil-water two-phase, process reproducibility is poor during reaction, and yi...

AI Technical Summary

Problems solved by technology

Although several production methods of mefenamic acid have been disclosed in the art, there are some deficiencies: for example, CN101475505A uses dimethylformamide, toluene, etc. as reaction solvents, and quaternary ammonium salts as phase transfer catalysts to prepare mefenamic acid

The production cost of this method is higher, and environmental pollution is heavier, and the difficulty of processing pollution is bigger; The deficiency of CN101704761A production method is, owing to be to react in oil-water two-phase, process reproducibility is poor during reaction, and yield is relatively low. Low, resulting in waste of raw materials, at the same time, it is easy to generate a large amount of foam when feeding materials during production, which is easy to pollute the production environment, and the production safety is low, etc.