反应详情

温度

180 °C

Method G-1: To a solution of 1-(3-benzyloxy-2-fluoro-6-nitrophenyl)-propan-2-one (3.03 g, 10 mmol) in acetic anhydride (5 mL) and acetic acid (5 mL) at room temperature was added hydrobromic acid (48% aqueous solution, 3 mL). After addition, the reaction was heated at 100° C. for 30 min and then cooled to room temperature. To this mixture was added 10 mL of hexanes with stirring. The solution was decanted and concentrated. The residue was diluted with ethyl acetate (50 mL) and washed with brine (3×20 mL). The organic layer was dried and concentrated in vacuo to provide 1-(2-fluoro-3-hydroxy-6-nitrophenyl)-propan-2-one (1.7 g, 80%) as a brown solid, which was used in the next step without further purification. LC/MS; (M+H)+=213.2 Method G-2: A mixture of 1-(3-benzyloxy-2-fluoro-6-nitrophenyl)-propan-2-one (65.0 g, 0.214 mol) and pyridinium chloride (60.74 g, 0.526 mol) was stirred at 180° C. for 1 hr. The reaction mixture was cooled to room temperature, diluted with 3N HCl (100 mL) and ethyl acetate (500 mL) and filtered. The aqueous layer was extracted with ethyl acetate (2×) and the combined organic layers were washed with brine, dried (MgSO4),s filtered through a pad of silica gel and concentrated in vacuo. The residue was decolorized with charcoal in methanol, filtered and concentrated in vacuo to afford 1-(2-fluoro-3-hydroxy-6-nitrophenyl)-propan-2-one (37 g, 81%) as a brown solid. LC/MS; (M+H)+=213.2

1. customwas used in the next step without further purification
2. temperatureThe reaction mixture was cooled to room temperature
3. filtrationfiltered
4. extractionThe aqueous layer was extracted with ethyl acetate (2×)
5. washthe combined organic layers were washed with brine, dried (MgSO4),s
6. filtrationfiltered through a pad of silica gel
7. concentrationconcentrated in vacuo
8. filtrationfiltered
9. concentrationconcentrated in vacuo