O-(7-Azabenzotriazol-1-yl)-N,N,N′,N′,-tetramethyluroniuum hexafluorophosphate (57 mg, 0.15 mmol) was added to a mixture of [7-[(4-fluorophenyl)methyl]-4-hydroxy-3-({[2-(methyloxy)ethyl]amino}carbonyl)-2-oxo-1,5-naphthyridine-1(2H)-yl]acetic acid, the title compound in Example 171 (50 mg, 0.12 mmol), triethylamine (0.02 mL, 0.15 mmol) and cyclobutylamine (0.012 mL, 0.15 mmol) in DMF (1 mL) at rt. After 1 h, the mixture was diluted with H2O (4 mL) and the title compound was collected by filtration to give a white solid: 1H NMR (d6-DMSO) δ 10.22 (1H, m), 8.54 (1H, s), 8.42 (1H, m), 7.75 (1H, s), 7.31 (2H, m), 7.10 (2H, m), 4.81 (2H, s), 4.13 (1H, m), 4.10 (2H, s), 3.52 (4H, m), 3.27 (3H, s), 2.09 (2H, m), 1.84 (2H, m), 1.59 (2H, m); HRMS calcd for C25H27FN4O5+H+: 483.2044. Found: 483.2049.
