Diisopropylethylamine → (S)-{1-[4,4-Bis-(4-fluoro-phenyl)-butylcarbamoyl]-3-methyl-butyl}-carbamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

N-tert-butoxycarbonyl-L-leucine (0.84 g, 3.4 mmol, Bachem Inc., Torrance, Calif.) was dissolved in dry DMF (7 mL) under nitrogen atmosphere and cooled to 0° C. in an ice-water bath. To this solution were added, in succession, N,N-diisopropylethylamine (1.8 mL, 10 mmol) and solid O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate (1.3 g, 3.4 mmol). The resulting reaction mixture was stirred at that temperature for 30 minutes; benzenebutanamine, 4,4-bis-(4-fluoro-phenyl)-butylamine monohydrochloride (1.0 g, 3.4 mmol) was then added. After additional 30 minutes stirring at 0° C., reaction mixture was mixed with 60 mL of diethyl ether; the resulting mixture was successively washed with 2% aqueous HCl solution, brine, saturated aqueous NaHCO3 solution, brine, and was dried over Na2SO4. Concentration in vacuo followed by drying under vacuum afforded 1.4 g (90%) of the pure titled compound was obtained as a white foam: mp 50-55° C. APCI-MS m/z 475.3 (MH+).

Provenance & Evidence