| production method | its preparation method is to use 1-methyl-4-ethoxycarbonylpyrazolamide as raw material, drop sulfuric acid in water, hydrochloric acid, acetic acid solution to heat up, dissolve pyrazolamide, then cool to 0 ℃, add sodium nitrite solution dropwise at 0~5 ℃ for diazotization reaction, the reaction is completed, slowly add the diazo liquid to the pre-prepared solution of sulfur dioxide in acetic acid, the reaction temperature is about 0 ℃, and a catalyst is added for reaction. After the reaction is completed, the excess sulfur dioxide is heated to remove, and the reaction solution is absorbed and reused with acetic acid. Add water, extract with dichloroethane to obtain pyrazole sulfonyl chloride dichloroethane solution, and heat to evaporate dichloroethane to obtain the finished product. |
