反应详情

To a stirred mixture of 5-(benzyloxy)-2-methoxybenzamide (9, 0.365 g. 1.4 mmol) and Ac2O (1.2 mL) at 0° C. was added 70% HNO3 (0.14 mL, 2.1 mmol). The reaction mixture was warmed to room temperature and stirred for 1 h. Then 4.5 mL of 70% HNO3 precooled at −30° C. was added. The mixture was stirred at 0° C. for 1 h and was poured onto ice. The precipitate was collected, washed with water and dried in vacuo. Purification by silica gel chromatography eluting with 0-2.5% MeOH in CH2Cl2 afforded the title compound along with its regioisomer (0.34 g, 79%) as a yellow solid: 1H NMR (500 MHz, CDCl3) δ 7.73 (br s, 1H), 7.41-7.30 (m, 5H), 7.11 (d, J=9.2 Hz, 1H), 7.00 (d, J=9.2 Hz, 1H), 6.84 (br s, 1H), 5.15 (s, 2H), 3.91 (s, 3H); ESI MS m/z 303 [M+H]+.

1. customprecooled at −30° C.
2. additionwas added
3. stirringThe mixture was stirred at 0° C. for 1 h
4. additionwas poured onto ice
5. customThe precipitate was collected
6. washwashed with water
7. customdried in vacuo
8. customPurification by silica gel chromatography
9. washeluting with 0-2.5% MeOH in CH2Cl2