反应详情

To a solution of 290 mg (1.0 mmole) of ethyl 5-fluoro-2-(trifluoromethyl)-2H-chromene-3-carboxylate in 7 mLs of THF and 2 mL of methanol was added a solution of 85 mg of lithium hydroxide monohydate in 1.0 mL of water. The mixture was heated to reflux for 30 min and allowed to cool to rt. After stirring overnight, the mixture was treated with 75 mL of 1N HCl and extracted three times with diethyl ether. The combined extracts were washed with brine, dried and concd in vacuo to afford 210 g (80%) of a white solid: 1H NMR (d6-acetone/400 MHz) 5.86 (q, 1H, J=7.1 Hz), 6.88 (m, 2H), 7.44 (q, 1H, J=6.7 Hz), 7.93 (s, 1H); 19F NMR (d6-acetone/400 MHz) −120.9 (t, 1F, J=7.7 Hz), −79.4 (d, 3F, J=7.7 Hz); MS (ES+) 263 (M+l, 100); MS (ES−) 261 (M−1, 100); HRMS (ES−) m/z calcd for (C11H6F4O3) 261.0175, found 261.0193.

1. temperatureThe mixture was heated
2. temperatureto reflux for 30 min
3. extractionextracted three times with diethyl ether
4. washThe combined extracts were washed with brine
5. customdried