Acetic Acid → Benzyl 4-(1-(tert-butoxycarbonyl)piperidin-4-yl)piperazine-1-carboxylate

Participants

Reaction Steps

1.89 g (30.1 mmol) of sodium cyanoborohydride were added to a stirred solution of 3.00 g (15.1 mmol) of tert-butyl 4-oxo-1-piperidinecarboxylate and 3.48 g (15.8 mmol) of 1-Z-piperazine in methanol (60 ml) at room temperature. The pH of the solution was adjusted to about pH 7 by dropwise addition of acetic acid and was monitored during the course of the reaction. The reaction mixture was stirred at room temperature overnight and then concentrated in vacuo. The residue was mixed with water (60 ml) and extracted with dichloromethane (4×60 ml). The combined organic phases were washed with saturated NaCl solution, dried over magnesium sulfate and concentrated in vacuo. The residue was purified by chromatography on silica gel (mobile phase gradient 3-10% methanol in dichloromethane). Yield: 3.41 g (56%) of colorless oil

Provenance & Evidence