Method for preparing sulfachlororyridazine sodium

Abstract

The invention discloses a method for preparing sulfachlororyridazine sodium, which belongs to the technical field of chemical synthesis. The method comprises the following steps of: performing chlorination reaction of 3,6-dihydroxypyridazine and a chlorinating agent to produce 3,6-dichlorophyridazine; reacting the 3,6-dichlorophyridazine with sulfanilamide and potassium carbonate, adding hot water and activated carbon for decoloring, performing filtration to remove the activated carbon, demixing filtrate, extracting supernatant, adding a diluted hydrochloric acid, adjusting a pH value of the mixed solution to be 4.0 to 5.0, performing the filtration, extracting solid matters and washing it with water to produce sulfachlorpyridazine; and finally reacting the sulfachlorpyridazine with the aqueous solution of sodium hydroxide, and performing cooling, crystallization and filtration to produce the sulfachlororyridazine sodium. The method has the advantage of simplifying a production operation process by directly entering the next condensation reaction after HPLC content measurement without taking the 3,6-dichlorophyridazine out as well as refining and purification, along with low production cost and high practical value.

Description

technical field [0001] The invention relates to a preparation method of a sulfonamide antibacterial agent-sulfachloropyridazine sodium, which belongs to the technical field of chemical synthesis. Background technique [0002] Sodium sulfachloropyridazine, chemical name: 3-p-aminobenzenesulfonamide sodium-6-chloropyridazine. White solid, melting point 180-183°C. Sulfachloropyridazine sodium is a widely used sulfonamide antibacterial agent for animals against gastrointestinal infections and coccidiosis caused by Escherichia coli. [0003] The preparation of existing sulfachloropyridazine sodium generally uses maleic anhydride and hydrazine hydrate ring expansion reaction to obtain 3,6-dihydroxypyridazine, obtains 3,6-dichloropyridazine through chlorination, then condenses with sulfonamide, and undergoes The target product was obtained after acid-base conversion. The chlorinating agent generally uses phosphorus oxychloride, which is more expensive, so that the production co...

AI Technical Summary

Problems solved by technology

Phosphorus oxychloride is generally used as the chlorinating agent, which is more expensive, so that the production cost of the final product remains high

In addition, because the post-treatment control of the chlorination reaction is relatively difficult, the reaction liquid must flow in parallel with ammonia water, and the temperature and acidity must be strictly controlled. The precipitated chlorides must be purified by melting and water separation, which is cumbersome to operate and is not conducive to improving product quality. , is not conducive to the protection of the environment

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