反应详情

温度

0 °C

To a stirred solution of 4-bromo-2-nitrobenzoic acid (3.81 g, 15 mmol) in DMF (30 mL) at 0° C. was added 1,8-diazabicycloundecane (DBU; 10.3 mL, 75 mmol) followed by MeI (4.67 mL, 75 mmol). The mixture was stirred for 15 min at 0° C., then was allowed to warm to rt and was stirred overnight. The mixture was poured into water and extracted with EtOAc (2×). The combined organic extracts were washed with water (2×), dried (MgSO4), and concentrated. The residue was purified by flash chromatography (hexanes/EtOAc) to afford methyl 4-bromo-2-nitrobenzoate as a pale yellow solid (3.52 g, 90%). To a solution of the nitrobenzoate (3.52 g, 13.5 mmol) in 1:1 EtOAc/DCM (30 mL) at rt was added SnCl2.2H2O (15.27 g, 67 mmol). After 18 h, the mixture was concentrated, diluted with satd. aq. NaHCO3, and extracted with DCM (3×). The combined organic layers were dried (MgSO4) and concentrated to provide the desired aminobenzoate as a white solid (2.89 g, 93%). 1H NMR (400 MHz, CDCl3): 7.70 (d, J=8.6, 1H), 6.84 (d, J=1.9, 1H), 6.75 (dd, J=8.6, 1.9, 1H), 5.78 (br s, 2H), 3.86 (s, 3H).

1. temperatureto warm to rt
2. stirringwas stirred overnight
3. extractionextracted with EtOAc (2×)
4. washThe combined organic extracts were washed with water (2×)
5. dry with materialdried (MgSO4)
6. concentrationconcentrated
7. customThe residue was purified by flash chromatography (hexanes/EtOAc)