Cesium carbonate → HCID 178423747, compound

Participants

Reaction Conditions

Reaction Steps

9-Hydroxy-5-[(iodophenyl)methyl]-2-(2-methylphenyl)-2,5-dihydro-3H-pyrazolo[4,3-c]quinolin-3-one (Example 728, 0.28 g, 0.56 mmol) was dissolved in tetrahydrofuran (5 mL) and treated with bis(tri-tert-butylphosphine)palladium(0) (57 mg, 0.11 mmol, 0.2 equiv), copper(I) chloride (55 mg, 0.56 mmol, 1 equiv), 2-methyl-5-pyridinylboronic acid (0.15 g, 1.1 mmol, 2 equiv) and an aqueous solution (2 mL) of cesium carbonate (0.45 g, 1.4 mmol, 2.5 equiv). The mixture was placed into a preheated oil bath at 70° C. for 2 hours, charged with additional boronic acid 2-methyl-5-pyridinylboronic acid (75 mg, 0.56 mmol, 1 equiv) and bis(tri-tert-butylphosphine)palladium(0) (27 mg, 0.056 mmol, 0.1 equiv). The mixture was heated for an additional 3 hours at 70° C., cooled to ambient temperature, poured into sodium bicarbonate (50 mL, aqueous saturated) and water (100 mL) and extracted with ethyl acetate (2×75 mL). The combined organic extracts were dried with sodium sulfate, filtered and concentrated in vacuo. The residue was purified by silica gel gradient chromatography (100:0 to 0:100; hexanes:ethyl acetate containing 10% methanol), providing the titled compound as a light yellow solid: 1H-NMR (400 MHz, CDCl3) δ 9.72 (1H, br s), 8.70 (1H, d, J=2.1 Hz), 8.45 (1H, s), 7.74 (1H, dd, J=8.0, 2.3 Hz), 7.58 (2H, d, J=8.0 Hz), 7.50-7.21 (4H, br m), 7.46 (1H, br m), 7.33 (2H, d, J=8.2 Hz), 7.23 (1H, d, J=8.0 Hz), 7.01 (1H, br s), 5.46 (2H, s), 2.60 (3H, s), 2.35 (3H, s) ppm; high resolution mass spectrometry (ES+) m/z 473.1985 [(M+H)+; calculated for C30H25N4O2: 473.1972].

Provenance & Evidence