Reaction Steps
2-(2-Aminophenyl)-5-{[4-(1H-pyrazol-1-yl)phenyl]methyl}-2,5-dihydro-3H-pyrazolo[4,3-c]quinolin-3-one (Example 626, 40 mg, 0.092 mmol), acetaldehyde (4.1 mg, 0.092 mmol, 1 equiv) and acetic acid (32 μL, 0.55 mmol, 6 equiv) were combined in tetrahydrofuran (1 mL) and stirred at ambient temperature for 10 minutes. The mixture was treated with sodium borohydride (1.2 mg, 0.046 mmol, 0.5 equiv) and after 2 hours at ambient temperature, the mixture was poured into water (5 mL) and extracted with ethyl acetate (2×5 mL). The combined organic extracts were dried with sodium sulfate, filtered and concentrated in vacuo. The residue was purified by preparative reverse phase HPLC (80:20 to 5:95; water containing 0.1% trifluoroacetic acid:acetonitrile containing 0.1% trifluoroacetic acid), providing the titled compound: 1H-NMR (400 MHz, d6-DMSO) δ 9.18 (1H, s), 8.46 (1H, d, J=2.5 Hz), 8.23 (1H, dd, J=7.7, 1.2 Hz), 7.83 (2H, d, J=8.6 Hz), 7.79 (1H, d, J=8.8 Hz), 7.72 (1H, d, J=1.2 Hz), 7.65-7.61 (1H, m), 7.55 (1H, t, J=7.8 Hz), 7.47 (2H, d, J=8.6 Hz), 7.37 (1H, dd, J=7.9, 1.2 Hz), 7.25-7.20 (1H, m), 6.82 (1H, d, J=8.1 Hz), 6.75 (1H, t, J=7.5 Hz), 6.53 (1H, br m), 5.79 (2H, s) 3.14 (2H, q, J=7.2 Hz), 1.18 (3H, t, J=7.0 Hz) ppm; low resolution mass spectrometry (ES+) m/z 461.0 [(M+H)+; calculated for C28H25N6O: 461.2].
