反应详情

To a round bottom flask equipped with magnetic stirring and a reflux condenser was added 3,4-dihydroxy-2-methylbenzoic acid (23.3 g, 139 mmol), methanol (139 mL), and concentrated sulfuric acid (0.77 mL, 13.9 mmol). This mixture was heated to reflux for 18 hours. The reaction was cooled to room temperature and the methanol evaporated. The residue was taken up in ether and washed once with saturated sodium bicarbonate solution, once with saturated sodium chloride solution, dried over sodium sulfate, filtered and evaporated to give a brown solid, methyl-3,4-dihydroxy-2-methylbenzoate, (20.9 g, 114 mmol) in 83% yield. 1H-NMR (300 MHz, CD3COCD3) δ (ppm): 2.47 (s, 3H), 3.79 (s, 3H), 6.78 (d, 1H), 7.46 (d, 1H); TLC: Rf=0.54 (1:1 ethyl acetate/hexane).

1. customTo a round bottom flask equipped
2. temperatureThis mixture was heated
3. temperatureto reflux for 18 hours
4. customthe methanol evaporated
5. washwashed once with saturated sodium bicarbonate solution, once with saturated sodium chloride solution
6. dry with materialdried over sodium sulfate
7. filtrationfiltered
8. customevaporated