反应详情

7-(3,5-dimethyl-4-isoxazolyl)-4-hydroxy-3-quinolinecarboxylate (for a preparation see Intermediate 9, 10 g, 35.21 mmol) was suspended by small portions to boiling diphenyl ether (200 ml) and allowed to reflux for 2 h. The reaction mixture was poured into hexane (500 ml) at 0° C., the precipitate was filtered and washed several times with hexane to give the title compound as a white solid (6.8 g, 86%). [APCI-MS] m/z: 240 MH+, Rt 1.89 min. 1H NMR (300 MHz, CDCl3, ppm) δ: 12.44 (brs, 1H), 8.67 (d, J=8.5 Hz, 1H), 8.10 (d, J=7.2 Hz, 1H), 7.80 (s, 1H), 7.62-7.55 (m, 1H), 7.25 (d, J=8.5 Hz, 1H), 6.61 (d, J=7.4 Hz, 1H), 2.64 (s, 3H), 2.49 (s, 3H).

1. temperatureto reflux for 2 h
2. filtrationthe precipitate was filtered
3. washwashed several times with hexane