反应详情

A solution of methyl 4-hydroxy-3-methoxy-5-(2-methylallyl)benzoate (150 g, 0.63 mol) in conc. HCl (300 mL) and MeOH (300 mL) was heated to reflux for 2 h. TLC (EtOAc/petroleum ether=1/5) showed the reaction was complete. The solution was evaporated, and the residue was extracted with EtOAc (200 mL×3). The combined organic phases were washed with brine (200 mL), dried over Na2SO4 and concentrated to give a brown oil. The crude oil was purified by column chromatography (EtOAc/petroleum ether=1/30) to give the title compound (80 g, 53%) as a white solid. 1H NMR (400 MHz, CDCl3): δ 7.51 (s, 1H), 7.46 (s, 1H), 3.91 (s, 3H), 3.87 (s, 3H), 3.05 (s, 2H), 1.53 (s, 6H).

1. temperatureto reflux for 2 h
2. customThe solution was evaporated
3. extractionthe residue was extracted with EtOAc (200 mL×3)
4. washThe combined organic phases were washed with brine (200 mL)
5. dry with materialdried over Na2SO4
6. concentrationconcentrated
7. customto give a brown oil
8. customThe crude oil was purified by column chromatography (EtOAc/petroleum ether=1/30)