Ammonium Acetate → Tert-butyl 4-amino-3,3-dimethylpiperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A slurry of tert-butyl 3,3-dimethyl-4-oxopiperidine-1-carboxylate (12.90 g, 56.8 mmol) and ammonium acetate (26.2 g, 341 mmol) in anhydrous methanol (40 mL) was stirred at room temperature under nitrogen for 3 h. After cooling to 0° C., sodium cyanoborohydride (1.783 g, 28.4 mmol) was added. The mixture was stirred at 0° C. for 5 min and at ambient temperature for 22 h. After removal of solvent in vacuo, the residue was treated with water (120 mL), stirred for 20 min, and extracted with dichloromethane (3×60 mL). The combined extracts were dried (MgSO4), concentrated and pumped under vacuum over weekend to give crude tert-butyl 4-amino-3,3-dimethylpiperidine-1-carboxylate (12.54 g). The purity of the product was not determined because of the lack of strong UV chromaphore in LCMS or HPLC, and presence of Boc rotamers in 1H NMR. The material was taken to the next reaction without further purification.

Provenance & Evidence