Acetic Acid → (S)-4-(3-Hydroxymethyl-oxetan-3-ylmethyl)-2-methyl-3-oxo-piperazine-1-carboxylic acid benzyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of (S)-2-[benzyloxycarbonyl-(2-oxo-ethyl)-amino]-propionic acid methyl ester (intermediate 27C; 258 mg, 0.92 mmol) in dichloromethane (1 mL) was added at room temperature to a suspension of (3-(aminomethyl)oxetan-3-yl)methanol (108 mg, 0.92 mmol), sodium triacetoxyborohyride (222 mg, 1.01 mmol) and acetic acid (111 mg, 1.85 mmol) in dichloromethane (1 mL). The reaction mixture was heated at 40° C. for 16 h, then partitioned between 1 M aq. sodium carbonate solution and ethyl acetate. The organic layer was washed with brine, dried (MgSO4), and evaporated. The residue was taken up in methanol (2 mL), then after addition of potassium carbonate (255 mg, 1.85 mmol) the suspension was stirred for 2 h. The reaction mixture was partitioned between sat. aq. ammonium chloride solution and ethyl acetate. The organic layer was washed with brine, dried (MgSO4), and evaporated. Chromatography (SiO2; dichloromethane/methanol/25% aq. ammonia solution 90:10:0.25) afforded the title compound (45 mg, 14%). Light yellow oil, MS (ISP)=349.3 (M+H)+.

Provenance & Evidence