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-phenoxypiperidin-1-yl)pyridin-2-amine (75 mg, 0.19 mmol), DMF (0.20 mL), ethanol (1.00 mL), 1M Na2S2O4 (3 eq, 0.58 mmol, 0.58 mL) and tert-butyl N-(4-formylbenzyl)carbamate (1.1 eq, 0.21 mmol, 49 mg). After 6 h, concentration in vacuo and purification by preparative tlc (CH2Cl2-MeOH, 95:5) gave the product (29 mg, 20%) as a colourless solid; δH (500 MHz, DMSO-d6) 1.41 (s, 9H, C(CH3)3), 1.84-1.90 (m, 2H, 2× piperidine CHAHB), 2.16-2.19 (m, 2H, 2× piperidine CHAHB), 3.59-3.64 (m, 2H, 2× piperidine NCHAHA), 3.87-3.91 (m, 2H, 2× piperidine NCHAHA), 4.19 (d, J=5.9 Hz, 2H, CH2NH), 4.70 (septet, J=3.9 Hz, 1H, piperidine CH), 6.94 (t, J=7.3 Hz, 1H, phenyl H-4), 7.04 (d, J=7.8 Hz, 2H, phenyl H-3′ & H-5′), 7.31 (dd, J=8.6, 7.4 Hz, 2H, phenyl H-3 & H-5), 7.40 (d, J=8.3 Hz, 2H, phenyl H-2 & H-6), 8.13 (d, J=8.1 Hz, 2H, phenyl H-2′ & H-6′), 8.24 (s, 1H, imidazo[4,5-b]pyridine H-5), 13.45 (s, br, 1H, imidazo[4,5-b]pyridine NH);
