2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → HCID 68153774, compound

Participants

Reaction Conditions

Reaction Steps

2-(3-oxo-5-{[4-(1H-pyrazol-1-yl)phenyl]methyl}-3,5-dihydro-2H-pyrazolo[4,3-c]quinolin-2-yl)benzaldehyde (Example 529, 75 mg, 0.17 mmol) was suspended in tetrahydrofuran (5 mL) and cooled to 0° C. Sodium cyanoborohydride (0.067 mL, 1 M tetrahydrofuran solution, 0.067 mmol, 0.4 equiv) was added dropwise and the mixture was stirred for 1 hour at 0° C. The mixture was diluted with dichloromethane (3 mL) until homogeneous and stirred for an additional 1 hour at 0° C. Sodium borohydride (1 spatula tip, excess) was added and the mixture was stirred at 0° C. for 30 minutes. The mixture was warmed to ambient temperature, opened to the air and treated with dichloro-5,6-dicyanobenzoquinone (DDQ, 40 mg, 0.17 mmol, 1 equiv). After stirring for 30 minutes, the mixture was poured into sodium bicarbonate (50 mL, aqueous saturated) and extracted with ethyl acetate (3×50 mL) and chloroform (3×50 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; then 100:0 to 0:100 ethyl acetate:ethyl acetate containing 5% methanol), providing the titled compound: 1H-NMR (400 MHz, CDCl3) δ 8.61 (1H, s), 8.35 (1H, d, J=7.4 Hz), 7.90 (1H, d, J=2.6 Hz), 7.72-7.70 (3H, m), 7.61 (1H, d, J=7.6 Hz), 7.57 (1H, d, J=7.5 Hz), 7.53 (1H, dd, J=7.6, 1.9 Hz), 7.51-7.47 (1H, m), 7.42 (1H, td, J=7.4, 1.5 Hz), 7.37 (1H, t, J=7.4 Hz), 7.29 (2H, d, J=8.6 Hz), 7.27 (1H, m), 6.47 (1H, m), 5.53 (2H, s), 5.21 (1H, br t, J=6.5 Hz), 4.53 (2H, d, J=5.8 Hz) ppm; high resolution mass spectrometry (ES+) m/z 448.1781 [(M+H)+; calculated for C27H22N5O2: 448.1768].

Provenance & Evidence