Dimethylformamide → tert-Butyl ((1S)-1-[bis(4-fluorophenyl)methyl]-2-[(2S,4S)-2-cyano-4-fluoro-1-pyrrolidinyl]-2-oxoethyl)carbamate

Participants

Reaction Conditions

Reaction Steps

A reactor was charged with N-{[(1,1-dimethylethyl)oxy]carbonyl}-4-fluoro-β-(4-fluorophenyl)-L-phenylalanine (400 g, 1 wt, 1 eq.), (2S,4S)-4-fluoropyrrolidine-2-carbonitrile para-toluenesulfonic acid (307.7 g, 0.77 wt, 1.01 eq.), O-(7-Azabenzotriazol-1-yl)-N,N,N,N-tetramethyluronium hexaflurophosphate [i.e. HATU] (408 g, 1.02 wt, 1.01 equiv.), and DMF (2.8L, 7 vol). The mixture was cooled to approximately 0° C. Hunig's base (376 mL, 0.94 vol, 2.04 equiv.) was added over at least 30 minutes. The mixture was heated to approximately 25° C. and was stirred at this temperature until the reaction was complete (ca. 3 hours). MTBE (2.8L mL, 7 vol) was added, followed by water (2L, 5 vol) over at least 30 minutes to quench the reaction. The aqueous phase was extracted with MTBE (1.2L, 3 vol). The combined organic phases were washed with water (2L, 5 vol). The organic phase was concentrated under vacuum to 3 volumes, and ethanol (1.6L, 4 vol) was added. The reaction was further concentrated under vacuum to 3 volumes, and ethanol (1.6 L, 4 vol) was added. The reaction was further concentrated under vacuum to 3 volumes. Added ethanol (2L, 5 vol). The ethanol solution of tert-Butyl {(1 S)-1-[bis(4-fluorophenyl)methyl]-2-[(2S,4S)-2-cyano-4-fluoro-1-pyrrolidinyl]-2-oxoethyl}carbamatewas used directly in the next step.

Provenance & Evidence