Reaction Steps
This was prepared using the same procedure as for 4-(6-bromo-2-(4-(dimethylamino)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)-N-phenylpiperazine-1-carboxamide, but here using 5-bromo-3-nitro-4-(4-(pyridin-3-ylmethyl)piperazin-1-yl)pyridin-2-amine (50 mg, 0.13 mmol), DMF (0.3 mL), ethanol (1.2 mL), 1M Na2S2O4 (3 eq, 0.38 mmol, 0.38 mL) and 4-(4-formylphenyl)piperazine-1-carboxylic acid tert-butyl ester (1.1 eq, 0.14 mmol, 43 mg). After 6 h, concentration in vacuo and purification by preparative tlc (CH2Cl2-MeOH, 95:5) gave the product (25 mg, 31%) as an off-white solid; δH (500 MHz, DMSO-d6) 1.43 (s, 9H, C(CH3)3), 2.61 (s, br, 4H, piperazine N(CH2)2), 3.26 (s, br, 4H, piperazine N(CH2)2), 3.48 (t, J=4.6 Hz, 4H, piperazine N(CH2)2), 3.61 (s, 2H, CH2), 3.64 (t, J=4.6 Hz, 4H, piperazine N(CH2)2), 7.06 (d, J=9.0 Hz, 2H, phenyl H-3 & H-5), 7.39 (dd, J=7.6, 4.7 Hz, 1H, pyridine H-5), 7.78 (d, br, J=7.7 Hz, 1H, pyridine H-4), 8.03 (d, J=8.9 Hz, 2H, phenyl H-2 & H-6), 8.17 (s, 1H, imidazo[4,5-b]pyridine H-5), 8.50 (dd, J=4.6, 1.5 Hz, 1H, pyridine H-6), 8.56 (d, J=1.4 Hz, 1H, pyridine H-2), 13.22 (s, br, 1H, imidazo[4,5-b]pyridine NH);
