反应详情

To a solution of 4-ethyl-3-hydroxy-benzoic acid (3.76 g, 22.6 mmol) in MeOH (70 mL), cc H2SO4 (0.7 mL) is added. The solution is refluxed overnight, 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 (CH2Cl2/MeOH 95:5)=0.7, MS (LC-MS): 179.2 [M−H]−, tR (HPLC, Nucleosil C18 column, 10-100% CH3CN/H2O/5 min, 100% CH3CN/2.8 min, flow: 1 ml/min): 4.86 min.

1. temperatureThe solution is refluxed overnight
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