反应详情

To a mixture of 1-(2-fluoro-4-hydroxy-phenyl)-ethanone (Alfa, 5 g, 32.5 mmol) in concentrated sulfuric acid (50 mL) at −5° C. was added KNO3 (3.29 g, 32.6 mmol) and the reaction mixture was stirred for 3 h. The reaction mixture was poured into ice water (500 mL) carefully and the aqueous solution was extracted with EtOAc (3×150 mL). The combined organic phase was washed with brine (100 mL), dried over anhydrous Na2SO4 and filtered. The filtrate was evaporated in vacuo and the residue was purified by column chromatography on silica gel (eluting with 2-10% EtOAc in petroleum ether) to give 1-(2-fluoro-4-hydroxy-5-nitro-phenyl)-ethanone as yellow solid (4.59 g, 71%). 1H NMR (CDCl3, 400 MHz): δ 10.95 (s, 1H), 8.79 (d, J=7.2 Hz, 1H), 6.92 (d, J=11.2 Hz, 1H), 2.63 (d, J=5.2 Hz, 3H).

1. extractionthe aqueous solution was extracted with EtOAc (3×150 mL)
2. washThe combined organic phase was washed with brine (100 mL)
3. dry with materialdried over anhydrous Na2SO4
4. filtrationfiltered
5. customThe filtrate was evaporated in vacuo
6. customthe residue was purified by column chromatography on silica gel (eluting with 2-10% EtOAc in petroleum ether)