Acetic Acid → tert-Butyl trans(+/-)-3-(benzylamino)-4-{[(4-chloro-5-ethyl-1H-imidazol-2-yl)carbonyl]amino}piperidine-1-carboxylate

Participants

Reaction Steps

Benzylamine (70 μL, 0.64 mmol), acetic acid (68.7 μL, 1.20 mmol) and sodium cyanoborohydride (42 mg, 0.667 mmol) were added to a mixed solution of tert-butyl 4-{[(4-chloro-5-ethyl-1H-imidazol-2-yl)carbonyl]amino}-3-oxopiperidine-1-carboxylate obtained in Example (201c) (99 mg, 0.267 mmol) in tetrahydrofuran (3 mL) and methanol (3 mL) under ice-cooling, and the mixture was stirred at room temperature for 15 hours. The reaction solution was concentrated under reduced pressure. Saturated aqueous sodium bicarbonate solution was added to the residue, followed by extraction with ethyl acetate. The resulting organic layer was washed with brine and dried over anhydrous sodium sulfate, and then the insoluble matter was separated by filtration. The filtrate was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography (eluent: chloroform:methanol=10:1 v/v) to obtain 26 mg of the cis isomer of the title compound (21%) as a colorless solid and 50 mg of the trans isomer of the title compound (41%) as a colorless solid.

Provenance & Evidence