A mixture of 3-{[(benzyloxy)carbonyl]amino}-7-bromoquinoline-2-carboxylic acid (0.50 g, 1.2 mmol), tert-butyl [(3S,5R)-1-(3-aminopyridin-4-yl)-5-methylpiperidin-3-yl]carbamate (0.38 g, 1.2 mmol), HATU (1.2 g, 3.1 mmol) in DMF (4.9 mL) and DIPEA (0.65 mL, 3.7 mmol) was stirred at room temperature for 2 h, then quenched with 50 mL of EtOAc and 30 mL of 1 M NaOH. The layers were separated and the aqueous phase was extracted with EtOAc. The combined organic extracts were concentrated under reduced pressure. The residue was purified by flash chromatography on 40 g silica gel column, eluting with 0-100% EtOAc in hexanes, to give the sub-title compound (0.435 g, 51%). LCMS calc. for C34H38BrN6O5[M+H]+: m/z=689.2. found: 689.3.
