Imidazole → 5-{[6-(1H-Imidazol-1-yl)pyridine-3-yl]methyl}-2-(2-methylphenyl)-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-methylphenyl)-2,5-dihydro-3H-pyrazolo[4,3-c]cinnolin-3-one [(Example 22) 80 mg, 0.18 mmol] was dissolved in dimethyl sulfoxide (1 mL) and treated with imidazole (49 mg, 0.72 mmol, 4 equiv), copper(I)iodide (14 mg, 0.072 mmol, 0.4 equiv), and (±)-trans-N,N′-dimethylcyclohexane-1,2-diamine (20 mg, 0.14 mmol, 0.8 equiv). An aqueous solution (0.2 mL) of tribasic potassium phosphate (0.11 g, 0.54 mmol, 3 equiv) was added and the mixture was placed into a preheated oil bath at 75° C. for 2 hours. The mixture was cooled to ambient temperature, poured into water and extracted twice with ethyl acetate. The combined organic extracts were washed once with water and brine, dried with sodium sulfate, filtered and concentrated in vacuo. The residue was purified by silica gel gradient chromatography (100:0 to 94:6; chloroform:methanol), providing the titled compound: 1H-NMR (400 MHz, CDCl3) δ 8.58 (1H, s), 8.43 (1H, br s), 8.33 (1H, d, J=6.9 Hz), 7.85 (1H, d, J=9.7 Hz), 7.77 (1H, br s), 7.68-7.54 (3H, m), 7.45 (1H, m), 7.38-7.32 (5H, m), 5.88 (2H, s), 2.36 (3H, s) ppm; high resolution mass spectrometry (ES+) m/z 434.1736 [(M+H)+; calculated for C25H20N7O: 434.1724].

Provenance & Evidence