反应详情

To a solution of 3-hydroxy-4-methyl-benzoic acid (5 g, 32.8 mmol) in MeOH (100 mL) cc H2SO4 (1 mL) is added. The solution is refluxed for 14 h, then concentrated to about 30 mL and poured into water. The aqueous layer is extracted with ether (50 mL×4) and the combined organic extracts are neutralized with a saturated aqueous solution of NaHCO3 (50 mL×2), washed with brine (50 mL), dried over Na2SO4, filtered and concentrated to give the title compound as a white powder. TLC, Rf (hexane/AcOEt 2:1 )=0.55. 1H-NMR (CDCl3, 300 MHz): δ=2.3 (s, 3H), 3.9 (s, 3H), 7.15 (d, 1H), 7.5 (d, 1H), 7.6 (s, 1H) ppm.

1. temperatureThe solution is refluxed for 14 h
2. concentrationconcentrated to about 30 mL
3. additionpoured into water
4. extractionThe aqueous layer is extracted with ether (50 mL×4)
5. washwashed with brine (50 mL)
6. dry with materialdried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated