反应详情

温度

200 °C

To a mixture of 2-amino-5-bromo-pyridine-3-carboxylic acid (1 g) and 2-amino-4-fluoro-phenol (0.586 g) placed in a round bottom flask was added polyphosphoric acid (10 g). The mixture was heated at 200° C. for 16 hours. After cooling, water (75 ml) was added and the mixture was stirred for 30 min. The mixture was basified to pH 12 with concentrated sodium hydroxide solution (6N and 2N). The solid was filtered, washed with water (150 ml×2), and ether (50 ml×2) to afford 5-bromo-3-(5-fluoro-1,3-benzoxazol-2-yl)pyridin-2-amine (1.0 g). NMR Spectrum: (DMSOd6) 7.53 (ddd, 1H), 7.93 (dd, 1H), 7.99-8.06 (m, 3H), 8.52 (d, 1H), 8.56 (d, 1H); Mass spectrum: M+H+ 308-310

1. customplaced in a round bottom flask
2. temperatureAfter cooling
3. filtrationThe solid was filtered
4. washwashed with water (150 ml×2), and ether (50 ml×2)