Allyl-5-[4-(1H-pyrazol-1-yl)benzyl]-2,5-dihydro-3H-pyrazolo[4,3-c]cinnolin-3-one [(Example 10), 600 mg, 1.57 mmol] was dissolved in tetrahydrofuran (65 mL) and water (65 mL), treated with 4-methylmorpholine 4-oxide (221 mg, 1.88 mmol, 1.2 equiv) and osmium tetroxide (50.0 μL, 0.160 mmol, 0.1 equiv). The mixture was stirred for 72 hours at ambient temperature, poured into sodium bicarbonate (200 mL, saturated aqueous) and extracted with ethyl acetate (2×150 mL) and chloroform (2×100 mL). The combined organic extracts were dried with sodium sulfate, filtered and concentrated in vacuo. The sodium sulfate was washed with a 1:1 mixture of methanol:chloroform (6×30 mL) and the filtrate was concentrated in vacuo. The residue was purified via silica gel gradient chromatography (100:0 to 85:15; dichloromethane:methanol), providing the titled compound: 1H-NMR (400 MHz, CDCl3) δ 8.30-8.26 (1H, m), 7.89 (1H, d, J=2.5 Hz), 7.72-7.67 (3H, m), 7.62-7.54 (3H, m), 7.39 (2H, d, J=8.4 Hz), 6.47-6.45 (1H, m), 5.88 (2H, s), 4.31 (2H, dd, J=5.3, 2.0 Hz), 4.18-4.13 (1H, m), 3.69-3.65 (2H, m), 3.49 (1H, d, J=5.8 Hz), 3.02 (1H, m); high resolution mass spectrometry (ES+) m/z 417.1684 [(M+H)+; calculated for C22H21N6O3: 417.1670].
