HCID 178469510, compound → 4-Quinolone-3-carboxylic acid

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Reaction Steps

4-Hydroxyquinoline-3-carboxylic acid ethyl ester (15 g, 69 mmol) was suspended in sodium hydroxide solution (2N, 150 mL) and stirred for 2 h at reflux. After cooling, the mixture was filtered, and the filtrate was acidified to pH 4 with 2N HCl. The resulting precipitate was collected via filtration, washed with water and dried under vacuum to give 4-oxo-1,4-dihydroquinoline-3-carboxylic acid as a pale white solid (10.5 g, 92%). 1H NMR (DMSO-d6) δ 15.34 (s, 1H), 13.42 (s, 1H), 8.89 (s, 1H), 8.28 (d, J=8.0 Hz, 1H), 7.88 (m, 1H), 7.81 (d, J=8.4 Hz, 1H), 7.60 (m, 1H).

Provenance & Evidence