反应详情

A solution of piperdine (1.16 g, 13.6 mmol), the title compound of Step 10 (3.0 g, 13.6 mmol) and NaHCO3 (3.94 g, 46.9 mmol) in EtOH (24 mL) was refluxed overnight in a modification of the procedure of Bach, et al. [J. Am. Chem. Soc. 79, 2221-2225 (1957)]. After filtration, the filtrate was concentrated to a yellow murky oil. The oil was dissolved into a 1.0M KOH solution (10 mL) and was extracted with EtOAc (3×5 mL). The organic layer was washed with a 5% NaHCO3, solution (5 mL), H2O (5 mL), and brine (5 mL) and then was dried over MgSO4. The filtrate was concentrated and purified by medium pressure column chromatography on silica gel [eluting NH4OH-EtOH-CHCl3 (1:5:94)] to give 1.85 g (58% yield) of the title compound as an oil. The proton spectral data were consistent with the proposed structure.

1. filtrationAfter filtration
2. concentrationthe filtrate was concentrated to a yellow murky oil
3. dissolutionThe oil was dissolved into a 1.0M KOH solution (10 mL)
4. extractionwas extracted with EtOAc (3×5 mL)
5. washThe organic layer was washed with a 5% NaHCO3, solution (5 mL), H2O (5 mL), and brine (5 mL)
6. dry with materialwas dried over MgSO4
7. concentrationThe filtrate was concentrated
8. custompurified by medium pressure column chromatography on silica gel [eluting NH4OH-EtOH-CHCl3 (1:5:94)]