6-methoxyquinoline-2-carboxylic Acid → 6-Hydroxyquinoline-2-carboxylic acid

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Reaction Steps

6-Methoxy-2-quinolinecarboxylic acid (80.6 g) was refluxed in 48% hydrobromic acid (450 ml) for twenty-four hours. After cooling to room temperature, the solid was collected by filtration and then dissolved in water (1300 ml) at 90° and the pH of this solution was adjusted to 8-9 with concentrated ammonium hydroxide. After cooling to room temperature, the pH of this solution was adjusted to 4-5 with acetic acid. The resulting 6-hydroxy-2-quinolinecarboxylic acid was collected by filtration and washed with water (400 ml); yield 70 g, m.p. 260°-261° (dec).

Provenance & Evidence