Acetic Acid → (S)-4-[(S)-3-((S)-4-Hydroxy-6-aza-spiro[2.5]oct-6-yl)-1-hydroxymethyl-propyl]-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, 2.35 g, 8.42 mmol) in dichloromethane (15 mL) was added at room temperature to a suspension of (S)-6-((S)-3-amino-4-hydroxy-butyl)-6-aza-spiro[2.5]octan-4-ol (1.81 g, 8.42 mmol), sodium triacetoxyborohyride (2.21 g, 1.01 mmol) and acetic acid (1.01 g, 16.8 mmol) in dichloromethane (15 mL). The reaction mixture was heated at 40° C. for 72 h, then partitioned between 1 M aq. sodium carbonate solution and ethyl acetate. The organic layer was washed with brine, dried (MgSO4), and evaporated. Chromatography (SiO2; dichloromethane→dichloromethane/methanol/25% aq. ammonia solution 90:10:0.25) produced the title compound (2.18 g, 58%). White foam, MS (ISP)=446.2 (M+H)+.

Provenance & Evidence