反应详情

5-Fluoro-2-methyl-6-nitro-benzoxazole (2.556 g, 13.03 mmol) was dissolved in Tetrahydrofuran (90 mL) and Acetic acid (4.5 mL, 79 mmol). Sodium borohydride (1.48 g, 39.1 mmol) was added and the reaction was stirred at room temperature for 90 min, then poured into 100 mL satd. sodium bicarbonate. The solution was extracted 3×50 mL DCM and the combined organics were washed with 1:1 brine:satd. sodium bicarbonate (50 mL) and dried over sodium sulfate, then conc. onto 10 g Celite. The crude product was chromatographed (120 g silica gel, ISCO, 0-20-40% EtOAc:Hex) to afford 2-Ethylamino-4-fluoro-5-nitro-phenol as a yellow solid (2.20 g, 84%). 1H-NMR (CDCl3): 7.55 (d, 1H, J=6.8 Hz), 6.26 (d, 1H, J=13.2 Hz), 5.51 (s, 1H), 5.05 (s, 1H), 3.26 (m, 2H), 1.34 (t, 3H, J=6.8 Hz).

1. additionpoured into 100 mL
2. extractionThe solution was extracted 3×50 mL DCM
3. washthe combined organics were washed with 1:1 brine
4. dry with materialsodium bicarbonate (50 mL) and dried over sodium sulfate
5. customThe crude product was chromatographed (120 g silica gel, ISCO, 0-20-40% EtOAc:Hex)