Ethanol → 2-(4-((1H-Pyrazol-1-yl)methyl)phenyl)-6-bromo-7-(4-(pyridin-4-ylmethyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine

Participants

Reaction Conditions

Reaction Steps

To a mixture of 5-bromo-3-nitro-4-(4-pyridin-4-ylmethyl-piperazin-1-yl)-pyridin-2-ylamine (0.039 g, 0.10 mmol) and EtOH (3.5 ml) was added 4-pyrazol-1-ylmethyl-benzaldehyde (0.024 g, 0.13 mmol) followed by a freshly prepared aqueous solution of Na2S2O4 (1M; 0.40 ml, 0.40 mmol). The reaction mixture was stirred at 80° C. for 20 h, then allowed to cool to room temperature and concentrated in vacuo. The resulting residue was absorbed on silica, and the free-running powder was placed on a 10 g isolute silica column. Elution with a gradient of methanol (2 to 5%) in ethyl acetate/dichloromethane (v:v; 1:1) afforded a solid. The title compound was obtained as a white solid after trituration with diethyl ether (0.025 g, 48%); 1H-NMR (500 MHz, DMSO-d6) 2.63 (br s, 4H, piperazine N(CH2)2), 3.61 (s, 2H, NCH2pyridyl), 3.69 (br s, 4H, piperazine N(CH2)2), 5.42 (s, 2H, C6H4CH2N), 6.30 (t, J=2.0 Hz, 1H, pyrazole 4-H), 7.35 (d, J=8.3 Hz, 2H) and 8.14 (d, J=8.2 Hz, 2H) (3,5-C6H4— and 2,6-C6H4—), 7.39 (d, J=5.9 Hz, 2H, pyridine 3-H, 5-H), 7.49 (d, J=1.7 Hz, 1H, pyrazole-H), 7.86 (d, J=2.2 Hz, 1H, pyrazole-H), 8.24 (s, 1H, imidazo[4,5-b]pyridine 5-H), 8.54 (d, J=5.9 Hz, 2H, pyridine 2-H, 6-H), 13.50 (br s, 1H, imidazo[4,5-b]pyridine N—H);

Provenance & Evidence