反应详情

A solution of 1-(N-tert-butoxycarbonylamino)cyclopropanecarboxylic acid (5 g) in tetrahydrofuran was cooled to −20° C. Isobutyl chloroformate (3.24 ml) and N-methylmorpholine (2.74 ml) were added thereto, and the mixture was stirred at the same temperature as above for 20 minutes. Then, sodium borohydride (1.12 g) and water (1 ml) were added thereto, and the mixture was further stirred at room temperature for 40 minutes. Water was added to the reaction solution, followed by extraction with ethyl acetate. The extract was washed with water and saturated saline in this order and then dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure. The obtained residue was purified by silica gel column chromatography (n-hexane-ethyl acetate) to obtain the title compound (4.24 g).

1. stirringthe mixture was further stirred at room temperature for 40 minutes
2. extractionfollowed by extraction with ethyl acetate
3. washThe extract was washed with water and saturated saline in this order
4. dry with materialdried over anhydrous sodium sulfate
5. distillationThe solvent was distilled off under reduced pressure
6. customThe obtained residue was purified by silica gel column chromatography (n-hexane-ethyl acetate)