A mixture of 4-fluoro-N2-pyridin-3-ylbenzene-1,2-diamine (1.03 g, 5.07 mmol), (S)-2-tertbutoxycarbonylaminopropionic acid (1.05 g, 5.58 mmol), HOAt (759 mg, 5.58 mmol), 4-methylmorpholine (1.23 mL, 11.15 mmol) and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (1.07 g, 5.58 mmol) in DCM (30 mL) was stirred at RT for 2 h. The reaction mixture was then partitioned between DCM and a saturated solution of NaHCO3. A precipitate was present in the organic fraction which was filtered off to afford the title compound as a pale yellow solid (503 mg). The filtrate was dried (MgSO4) and concentrated in vacuo and the resulting residue was triturated with DCM to afford a second batch of the title compound as a yellow solid (765 mg; 67% yield for the combined batches). LCMS (Method C): RT 2.06 min [M+H]+ 375.3
