Cesium carbonate → 2-(2,3-dimethylphenyl)-5-[(6'-methyl-2,3'-bipyridin-5-yl)methyl]-2,5-dihydro-3H-pyrazolo[4,3-c]cinnolin-3-one

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Reaction Steps

5-[(6-Bromopyridin-3-yl)methyl]-2-(2,3-dimethylphenyl)-2,5-dihydro-3H-pyrazolo[4,3-c]cinnolin-3-one (0.10 g, 0.22 mmol), (6-methylpyrdin-3-yl)-boronic acid (74 mg, 0.54 mmol, 2.5 equiv), palladium(II)acetate (9.7 mg, 0.043 mmol, 0.2 equiv), 1,1′-bis(diphenylphosphino)ferrocene (24 mg, 0.043 mmol, 0.2 equiv), copper(I)chloride (21 mg, 0.22 mmol, 1 equiv) and cesium carbonate (0.18 g, 0.54 mmol, 2.5 equiv) were combined in N,N-dimethylformamide (4 mL) and placed into an oil bath preheated to 100° C. for 60 minutes. The mixture was cooled to ambient temperature, poured into sodium bicarbonate (20 mL, aqueous saturated) and extracted with ethyl acetate (3×25 mL). The combined organic extracts were dried with sodium sulfate, filtered and concentrated in vacuo. The residue was purified by silica gel chromatography (100:0 to 90:10; dichloromethane:methanol), providing the titled compound as a deep red solid: 1H-NMR (400 MHz, CDCl3) δ 9.06 (1H, d, J=2.1 Hz), 8.78 (1H, d, J=1.7 Hz), 8.32 (1H, dd, J=7.8, 1.0 Hz), 8.19 (1H, dd, J=8.1, 2.3 Hz), 7.77 (1H, dd, J=8.3, 2.4 Hz), 7.72 (1H, d, J=8.3 Hz), 7.65-7.54 (3H, m), 7.42-7.38 (1H, m), 7.30-7.22 (3H, m), 5.90 (2H, s), 2.61 (3H, s), 2.37 (3H, s), 2.20 (3H, s) ppm; high resolution mass spectrometry (ES+) m/z 473.2099 [(M+H)+; calculated for C29H25N6O: 473.2084].

Provenance & Evidence