Acetic Acid → tert-Butyl cis(+/-)-4-{[(benzyloxy)carbonyl]amino}-3-(dimethylamino)piperidine-1-carboxylate

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Reaction Steps

A 37% aqueous formaldehyde solution (346 μL, 4.26 mmol), acetic acid (110 μL, 1.92 mmol) and sodium cyanoborohydride (67 mg, 1.07 mmol) were added to a mixed solution of tert-butyl cis(±)-3-amino-4-{[(benzyloxy)carbonyl]amino}piperidine-1-carboxylate obtained in Example (200a) (149 mg, 0.43 mmol) in tetrahydrofuran (2 mL) and methanol (2 mL) under ice-cooling, and the mixture was stirred at room temperature for two hours. The reaction solution was concentrated under reduced pressure, and aqueous saturated sodium bicarbonate solution was added to the residue, followed by extraction with chloroform. The resulting organic layer was 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 152 mg of the title compound (94%) as a colorless oily substance.

Provenance & Evidence