反应详情

温度

70 °C

Methyl 4-(N-t-butoxycarbonyl-4-piperidinyloxy)-2-methoxybenzoate (35 g, 96 mmol) from Step 5 above was dissolved in MeOH (250 mL) and to the solution was added 2 N NaOH (100 ML, 200 mmol). The stirred mixture was warmed to 70° C. for 3 h. The solution was cooled to ambient temperature, concentrated under reduced pressure, cooled to 0° C. and 0.5M aqueous citric acid solution (300 mL) was added. To the suspension was added EtOAc (500 mL) and water (300 mL). The EtOAc layer was separated and the aqueous phase was washed with EtOAc (200 mL). The combined EtOAc layers were washed with brine (250 mL), dried (MgSO4), filtered, and the solvent was removed under reduced pressure to give 4-(N-t-butoxycarbonyl-4-piperidinyloxy)-2-methoxybenzoic acid as a foam that solidified on standing in vacuo (HPLC (method A) retention time= 8.46 min).

1. temperatureThe solution was cooled to ambient temperature
2. concentrationconcentrated under reduced pressure
3. temperaturecooled to 0° C.
4. addition0.5M aqueous citric acid solution (300 mL) was added
5. additionTo the suspension was added EtOAc (500 mL) and water (300 mL)
6. customThe EtOAc layer was separated
7. washthe aqueous phase was washed with EtOAc (200 mL)
8. washThe combined EtOAc layers were washed with brine (250 mL)
9. dry with materialdried (MgSO4)
10. filtrationfiltered
11. customthe solvent was removed under reduced pressure