反应详情

温度

70 °C

6-Hydroxyquinoline-3-carboxylic acid (Int-15, 1 g, 5.29 mmol) was suspended in methanol (25 mL) to which sulfuric acid (0.3 mL, 5 mmol) was carefully added. The reaction was heated at 70° C. under an atmosphere of nitrogen for 48 h. The reaction was cooled to room temperature and saturated sodium bicarbonate solution (2 mL) was added. The solvent was removed under reduced pressure and the crude residue was co-evaporated with toluene twice. The dried residue was purified by silica gel chromatography (methylene chloride to 95/5 methylene chloride/methanol gradient) to afford Int-16 (0.89 g, 83%). LC-MS: (FA) ES+ 204; 1H NMR (400 MHz, d6-DMSO) δ ppm 9.23 (d, J=1.7 Hz, 1H), 9.09 (s, 1H), 8.05 (d, J=9.1 Hz, 1H), 7.59 (dd, J=9.1, 2.5 Hz, 1H), 7.50 (d, J=2.5 Hz, 1H), 3.96 (s, 3H).

1. additionwas carefully added
2. temperatureThe reaction was cooled to room temperature
3. customThe solvent was removed under reduced pressure
4. customThe dried residue was purified by silica gel chromatography (methylene chloride to 95/5 methylene chloride/methanol gradient)
5. customto afford Int-16 (0.89 g, 83%)