反应详情

温度

7.5 °C

Added 3′-fluoroacetanilide (3.06 g, 20 mmol) cautiously to conc sulfuric acid (6 mL) at 5° C. To the resulting solution, added fuming nitric acid (1.05 mL, 25 mmol) dropwise while maintaining temperature at 5-10° C. After 30 min, added ice (50 g), later diluted with water (100 mL) and extracted with EtOAc (2×100 mL). The combined organic layers were washed with saturated NaHCO3 and brine, dried (Na2SO4) and concentrated to give the crude product (4.0 g) as a mixture of isomers (1:1.4 ratio of 4′-nitro/2′-nitro). The desired isomer, 3′-flouro-4′-nitroacetanilide, was isolated by flash chromatography (DCM-5% MeOH/DCM) in low yield (1.2 g, 30%) as a yellow solid. 1H-NMR (CDCl3): δ 8.08 (1H, app t), 7.82 (1H, dd), 7.41 (1H, br s), 7.21 (1H, m), 2.25 (3H, s).

1. extractionextracted with EtOAc (2×100 mL)
2. washThe combined organic layers were washed with saturated NaHCO3 and brine
3. dry with materialdried (Na2SO4)
4. concentrationconcentrated
5. customto give the crude product (4.0 g)
6. additionas a mixture of isomers (1:1.4 ratio of 4′-nitro/2′-nitro)