반응 #58029
ord-86baea5576f147ec9e8b1b1bc871edf2
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시약
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후처리
- 1온도The mixture was heated
- 2온도at reflux for 3 h
- 3기타to attain room temperature
- 4세척the mixture was washed with NaHCO3 (sat.) and brine
- 5기타The organic phase was dried
- 6여과filtered
- 7농축concentrated
- 8workup.DISSOLUTIONThe residue was dissolved in a mixture of EtOH (40 mL) and acetic acid (20 mL)
- 9추출The solution was extracted several times with dichloromethane
- 10기타The combined organic phases were dried
- 11여과filtered
- 12농축concentrated
- 13여과filtered through a pad of silica gel (dichloromethane)
- 14기타The solvent was evaporated
실험 절차
To a solution of meldrums acid (1.68 g, 11.66 mmol) and 4-(2-oxo-ethyl)-piperidine-1-carboxylic acid tert-butyl ester (2.21 g, 9.72 mmol) in dichloromethane (40 mL) was added acetic acid (0.055 mL, 0.972 mmol) and piperidine (0.096 mL, 0.972 mmol). The mixture was heated at reflux for 3 h, and then allowed to attain room temperature. After being diluted with tert-butyl methyl ether, the mixture was washed with NaHCO3 (sat.) and brine. The organic phase was dried, filtered and concentrated. The residue was dissolved in a mixture of EtOH (40 mL) and acetic acid (20 mL). The solution was cooled to 0° C., and NaBH4 (0.554 g, 14.6 mmol) was added in portions after which the solution was allowed to stir for 30 min at rt and then acidified to pH 3 with 1 M HCl. The solution was extracted several times with dichloromethane. The combined organic phases were dried, filtered, concentrated and filtered through a pad of silica gel (dichloromethane). The solvent was evaporated to give 4-[2-(2,2-Dimethyl-4,6-dioxo-[1,3]dioxan-5-yl)-ethyl]-piperidine-1-carboxylic acid tert-butyl ester as a colorless oil (2.30 g, 65%) which solidified on standing.