反应详情

A solution of ethyl 3-(3-methoxy-2-methylphenyl)propanoate (36.3 g, 165 mmol, from Step B) in abs. EtOH (200 mL) and 5 N NaOH (99 mL) was heated to reflux for 30 min and cooled to ambient temperature. The reaction mixture was concentrated in vacuo, and the resultant solid mass was dissolved in H2O (100 mL) and cooled in an ice bath. Concentrated HCl (50 mL) was then added dropwise. At pH=4, an additional 300 mL H2O was added to facilitate stirring. The acidified mixture was stirred for 30 min, filtered, and the solids washed with H2O (2×100 mL) and Et2O (2×100 mL). After 3 hr, the solids were dried over P2O5 in vacuo overnight to give 29.3 g of the title compound as a white solid: 1H NMR (500 MHz, CD3OD) δ 2.15 (s, 3H), 2.50 (t, 2H, J=7.9 Hz), 2.90 (t, 2H, J=7.9 Hz), 3.78 (s, 3H), 6.75 (d, 2H, J=8.0 Hz), 7.05 (t, 1H, J=8.0 Hz).

1. temperatureto reflux for 30 min
2. concentrationThe reaction mixture was concentrated in vacuo
3. dissolutionthe resultant solid mass was dissolved in H2O (100 mL)
4. temperaturecooled in an ice bath
5. additionConcentrated HCl (50 mL) was then added dropwise
6. additionAt pH=4, an additional 300 mL H2O was added
7. stirringThe acidified mixture was stirred for 30 min
8. filtrationfiltered
9. washthe solids washed with H2O (2×100 mL) and Et2O (2×100 mL)
10. dry with materialthe solids were dried over P2O5 in vacuo overnight