反应详情

To a mixture containing 4-bromo-3-hydroxybenzoic acid (5.0 g, 0.023 mol) and 5 ml of EtOH in 150 ml of benzene was added 1 ml of MeSO3H. The mixture was heated at reflux for 10 h using a Dean-Stark trap to collect water, then concentrated. The residue was dissolved in CH2Cl2, washed (water, 5% NaHCO3, and brine), dried (Na2SO4), and concentrated. The crude product was chromatographed (EtOAc/hexane) to gave a white solid (5.1 g, 90%): 1H NMR (300 MHz, CDCl3) δ 1.39 (t, J=7.2 Hz, 3 H), 4.37 (q, J=7.2 Hz, 2 H), 5.75 (s, 1 H), 7.48 (d, J=8.1 Hz, 1 H), 7.55 (d, J=8.1 Hz, 1 H), 7.68 ppm (s, 1 H).

1. temperatureThe mixture was heated
2. temperatureat reflux for 10 h
3. customto collect water
4. concentrationconcentrated
5. dissolutionThe residue was dissolved in CH2Cl2
6. washwashed (water, 5% NaHCO3, and brine)
7. dry with materialdried (Na2SO4)
8. concentrationconcentrated
9. customThe crude product was chromatographed (EtOAc/hexane)