反应详情

A mixture of 3-hydroxy-4-methylbenzoic acid (25.42 g, 167 mmol) (TCl US) and concentrated sulfuric acid (3 mL) in absolute ethanol (180 mL) was heated at reflux for 20 hours. After cooling, solid sodium bicarbonate (10 g) was added to neutralize the acid. Mixture was partitioned between diethyl ether (2×400 mL) and water (2×300 mL). Organic layers were washed with brine (300 mL), combined, dried (MgSO4), filtered, and concentrated. Residue was recrystallized from hexanes to give 3-hydroxy-4-methyl-benzoic acid ethyl ester as white crystals in two crops. (Yield 29.14 g, 96.8%).

1. temperaturewas heated
2. temperatureat reflux for 20 hours
3. temperatureAfter cooling
4. customMixture was partitioned between diethyl ether (2×400 mL) and water (2×300 mL)
5. washOrganic layers were washed with brine (300 mL)
6. dry with materialdried (MgSO4)
7. filtrationfiltered
8. concentrationconcentrated
9. customResidue was recrystallized from hexanes