反应详情

The ester ethyl 4-(3'-methoxyphenyl)-1-methylpiperidine-3-carboxylate (23 (5.0 g, 17.5 mmol), NaOH (1.49 g, 35 mmol), CH3OH (50 mL), and H2O (25 mL) were refluxed for 5 h. After the thorough removal of solvents, the residue was mixed with acetic anhydride (50 mL) and refluxed for 1 h, then cooled and evaporated and the crude reaction product partitioned between CHCl3 (50 mL) and saturated NaHCO3 (50 mL, pH 8). The aqueous layer was extracted with CHCl3 (2×50 mL) and the combined organic phases dried and evaporated. Distillation gave 3.77 g (92%) of 4-(3'-methoxyphenyl)-1-methyl-3-methylene-2-piperidone (24). Recrystallization (CH3Cl2 /hexane) gave the analytical sample: mp 67°-70° C.: NMR δ 7.29 (m, 1 H), 6.82 (m, 3H), 6.40 (t,J=2 Hz, 1H), 5.07 (t,J=2 Hz, 1H), 3.75 (s, 3H), 3.34 (m, 2H), 3.04 (s, 3H), 2.17 (m, 2H); IR (KBr) 1645, 1600 cm-1 ; mass spectrum m/e (rel intensity) 231 (100), 216 (13). Anal. Calcd for C14H17NO2 : C, 72.7; H, 7.4; N, 6.1. Found: C, 72.6; H, 7.3; N, 6.0.

1. customAfter the thorough removal of solvents
2. additionthe residue was mixed with acetic anhydride (50 mL)
3. temperaturerefluxed for 1 h
4. temperaturecooled
5. customevaporated
6. customthe crude reaction product
7. custompartitioned between CHCl3 (50 mL) and saturated NaHCO3 (50 mL, pH 8)
8. extractionThe aqueous layer was extracted with CHCl3 (2×50 mL)
9. customthe combined organic phases dried
10. customevaporated
11. distillationDistillation