To a solution of N1-cyclopropyl-6-fluorobenzene-1,2-diamine (392.7 mg, 2.363 mmol) in DMF (3 mL) was added Boc-L-Ala-OH (447 mg, 2.363 mmol), 1,1′-dimethyltriethylamine (822 μL, 4.73 mmol) and (1H-benzo[d][1,2,3]triazol-1-yloxy)tripyrrolidin-1-ylphosphonium hexafluorophosphate(V) (1.23 mg, 2.36 mmol) and the resulting mixture was stirred at rt for 4 h. The reaction mixture was diluted with EtOAc, washed with water and brine, dried over MgSO4, and concentrated under reduced pressure. The residue was purified by column chromatography on a silica gel column using EtOAc:DCM (1:1) as eluent to give (S)-tert-butyl 1-(2-(cyclopropylamino)-3-fluorophenylamino)-1-oxopropan-2-ylcarbamate: LC-MS (ESI) m/z 338.2 [M+H]+.
