反应详情

温度

55 °C

To a solution of 3-chloro-4-hydroxy-benzoic acid hemihydrate (9.08 g, 50 mmol) in methanol (150 mL) is added slowly (conc)sulfuric acid (22.5 mL). The resulting solution is heated to 55° C. and stirred 2 hours then cooled to 20° C. Poured solution into ice and extracted with ether. The organic is washed with brine, dried over MgSO4 and concentrated. The residue is purified by flash chromatography (eluting with 30% ethyl acetate in hexanes) to give 9.5 g of title compound as a white crystalline solid. 1H NMR (CDCl3) δ 3.90 (s, 3H), 7.06 (d, J=9 Hz, 1H), 7.88 (dd, J=9, 2 Hz, 1H), 8.05 (d, J=2 Hz, 1H). MS (EI) m/z 186/188 (M+, Cl).

1. temperaturethen cooled to 20° C
2. extractionPoured solution into ice and extracted with ether
3. washThe organic is washed with brine
4. dry with materialdried over MgSO4
5. concentrationconcentrated
6. customThe residue is purified by flash chromatography (eluting with 30% ethyl acetate in hexanes)