The Kolbe-Schmitt Reaction in Aqueous Solutions
Naoki MORINAGA, Mikiko UCHIGASHIMA, Mohammad Abdur RAHIM, Kazutoshi ONISHI, Kazufumi TAKAHASHI and Yoshio KOSUGI*
Advanced Organic Material Chemistry, Department of Material Science, Faculty of Science & Engineering, Shimane University; Nishikawatsu, Matsue-shi 690-8504 Japan
The carboxylation of m-aminophenol with potassium hydrogencarbonate in aqueous solutions has been studied kinetically. The formation of 4-hydroxyanthranilic acid (4HAA) has been found for the first time in the carboxylation of m-aminophenol which gives only p-aminosalicylic acid (pAS) in the usual Kolbe-Schmitt reaction. Since 4HAA was easily decarboxylated, the product was removed from the reaction mixture after the carboxylation for 1 h at 60 °C. This method was repeated three times and 4HAA was obtained as a major product in 30.2% yield.
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