反应详情

4-Amino-1-boc-piperidine (205 mg, 1.02 mmol) and triethylamine (0.143 μL, 1.02 mmol) in tetrahydrofuran (5 mL) were added to a solution of p-nitrophenylchloroformate (206 mg, 1.02 mmol) in tetrahydrofuran (15 mL) at 0° C. After 1 h, additional triethylamine was added (0.286 mL, 2.04 mmol) along with DL-valine methyl ester hydrochloride (134 mg, 1.02 mmol). The reaction warmed to ambient temperature and was then heated to 50° C. After 2 h, the mixture was filtered, concentrated and redissolved in ethyl acetate. The ethyl acetate layer was washed with 1N sodium hydroxide (3×), saturated sodium bicarbonate solution, water, brine, and dried over sodium sulfate. Purification by silica gel chromatography (100% dichloromethane→7% methanol {1% ammonium hydroxide}/dichloromethane) gave the title compound (300 mg). MS 358.28 (M+1)

1. temperaturewas then heated to 50° C
2. waitAfter 2 h
3. filtrationthe mixture was filtered
4. concentrationconcentrated
5. dissolutionredissolved in ethyl acetate
6. washThe ethyl acetate layer was washed with 1N sodium hydroxide (3×), saturated sodium bicarbonate solution, water, brine
7. dry with materialdried over sodium sulfate
8. customPurification by silica gel chromatography (100% dichloromethane→7% methanol {1% ammonium hydroxide}/dichloromethane)