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 (200 mg, 0.51 mmol), DMF (0.45 mL), ethanol (2.55 mL), 1M Na2S2O4 (3 eq, 1.53 mmol, 1.53 mL) and tert-butyl N-(3-formylbenzyl)carbamate (1.1 eq, 0.21 mmol, 132 mg). After 18 h, concentration in vacuo and column chromatography (CH2Cl2-MeOH, 95:5) gave the product (89 mg, 30%) as a colourless solid; δH (500 MHz, DMSO-d6) 1.38 (s, 9H, C(CH3)3), 2.62 (s, br, 4H, piperazine N(CH2)2), 3.61 (s, 2H, NCH2Ar), 3.66 (s, br, 4H, piperazine N(CH2)2), 4.22 (d, J=6.0 Hz, 2H, CH2NH—BOC), 7.36 (d, J=7.7 Hz, 1H, phenyl H-4 or H-6), 7.39 (dd, J=7.7, 2.7 Hz, 1H, pyridine H-5), 7.45 (t, br, J=5.7 Hz, 1H, NH—BOC), 7.48 (t, J=7.7 Hz, 1H, phenyl H-5), 7.78 (d, J=7.6 Hz, 1H, pyridine H-4), 8.01 (d, J=7.7 Hz, 1H, phenyl H-4 or H-6), 8.10 (s, br, 1H, phenyl H-2), 8.25 (s, 1H, imidazo[4,5-b]pyridine H-5), 8.50 (d, br, J=3.5 Hz, 1H, pyridine H-6), 8.57 (s, br, 1H, pyridine H-2), 13.52 (s, br, 1H, imidazo[4,5-b]pyridine NH);
