Prodn. of acetylsalicylic acid ester of (N)-acetyl-(p)-aminophenol - by reacting corresp. salicylic acid ester with acetic anhydride using sodium salts as catalysts

摘要

Prodn. of the acetylsalicylic acid ester of N-acetyl-p-aminophenol comprises reacting acetic anhydride with the corresp. salicycli acid ester (phenetsal). Reaction is carried out at 60-90 degrees C using sodium (bi)carbonate or acetate as catalyst. The reaction is pref. carried out using excess acetic anhydride or DMF as solvent. Use of the above catalysts allows a higher reaction temp. and faster reaction than when using pyridine or quinoline and gives 95% yield. In an example, 12g (96% yield) of the prod. ester was prepd. from 10.8g phenetsal, 25 ml. acetic anhydride and 5g sodium acetate.