4-(R)-[1-[N-(tert-butoxycarbonyl)-N-(ethyl)Amino]Cyclopropyl]-1-[1-(S)-phenylethyl]Pyrrolidin-2-one → 3-(R)-[1-[N-(tert-butoxycarbonyl)-N-(ethyl)Amino]Cyclopropyl]-1-[1-(S)-phenylethyl]Pyrrolidine

Participants

Reaction Steps

4-(R)-[1-[N-(tert-butoxycarbonyl)-N-(ethyl)amino]cyclopropyl]-1-[1-(S)-phenylethyl]pyrrolidin-2-one (4.56 g, 12.1 mmol) was dissolved in anhydrous tetrahydrofuran (80 ml), and a 1.0M borane-tetrahydrofuran complex/tetrahydrofuran solution (48.0 ml, 48.0 mmol) was added dropwise in while stirring and cooling with ice. After completion of dripping, the reaction solution was stirred for 16 hours under the condition of from ice cooling to room temperature. After concentrating the reaction solution under a reduced pressure, a 9:1 mixed solution (100 ml) of ethanol and water was added thereto, and after adding triethylamine (5 ml), it was heated under reflux for 4 hours. After cooling the reaction solution to room temperature, concentration was performed under a reduced pressure, saturated sodium bicarbonate water (100 ml) was added to the residue, extraction with chloroform (100 ml×2) was performed, and then the combined organic layer was washed with saturated saline solution (100 ml) and then dried over anhydrous sodium sulfate. After filtering, the filtrate was concentrated under a reduced pressure, the concentrate was applied to a silica gel chromatography, and 4.26 g (99%) of the title compound was obtained in the form of a colorless syrup from a chloroform:methanol=100:1 to 95:5 eluate.

Provenance & Evidence