反应详情

To a stirred solution of methyl 3-amino-5-bromobenzoate (5.2 g, 23 mmol) in water (80 mL) and H2SO4 (60 mL) was added dropwise a solution of NaNO2 (1.9 g, 28 mmol) in water (10 mL) at 0° C. The reaction mixture was added to a mixture of water (180 mL) and H2SO4 (240 mL). The mixture was heated at reflux for 30 minutes before being cooled to room temperature. The resulting mixture was poured into crushed ice and extracted with ethyl acetate (100 mL×3). The combined organic layers were washed with brine and water, dried over anhydrous Na2SO4, and concentrated under vacuum to afford 3-bromo-5-hydroxybenzoic acid (3.8 g, 78% yield), which was directly used in next step. 1H NMR (400 MHz, d-DMSO) δ 10.27 (s, 1H), 7.43 (t, J=1.6 Hz, 1H), 7.28 (dd, J=1.2, 2.0 Hz, 1H), 7.15 (t, J=2.0 Hz, 1H).

1. temperatureThe mixture was heated
2. temperatureat reflux for 30 minutes
3. additionThe resulting mixture was poured
4. custominto crushed ice
5. extractionextracted with ethyl acetate (100 mL×3)
6. washThe combined organic layers were washed with brine and water
7. dry with materialdried over anhydrous Na2SO4
8. concentrationconcentrated under vacuum