反应详情

To a suspension of 3-hydroxy-4-(methyloxy)benzoic acid (25 g, 149 mmol.) in methanol (200 mL) was added concentrated sulfuric acid (1 mL) and the mixture was brought to reflux over 18 hours. The resulting homogeneous solution was cooled to room temperature, concentrated in vacuo and the residual oil taken into ethyl acetate (300 mL). The solution was washed once with water, saturated aqueous sodium hydrogencarbonate then brine and dried over anhydrous magnesium sulfate. Filtration and concentration gave methyl 3-hydroxy-4-(methyloxy)benzoate (27 g, 100% yield) as an oil. 1H NMR (400 MHz, CDCl3): 7.59 (dd, 1H), 7.57 (d, 1H), 6.85 (d, 1H), 5.72 (s, 1H), 3.93 (s, 3H), 3.87 (s, 3H).

1. temperatureto reflux over 18 hours
2. concentrationconcentrated in vacuo
3. washThe solution was washed once with water, saturated aqueous sodium hydrogencarbonate
4. dry with materialbrine and dried over anhydrous magnesium sulfate
5. filtrationFiltration and concentration