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 4-(4-benzylpiperidin-1-yl)-5-bromo-3-nitropyridin-2-amine (100 mg, 0.25 mmol), DMF (0.20 mL), ethanol (1.25 mL), 1M Na2S2O4 (3 eq, 0.75 mmol, 0.75 mL) and tert-butyl N-(4-formylbenzyl)carbamate (1.1 eq, 0.28 mmol, 66 mg). After 6 h, concentration in vacuo and purification by preparative tlc (CH2Cl2-MeOH, 95:5) gave the product (32 mg, 22%) as a colourless solid; δH (500 MHz, DMSO-d6) 1.41 (s, 9H, C(CH3)3), 1.44-1.49 (m, 2H, 2× piperidine CHAHB), 1.73 (app d, J=11.0 Hz, 2H, 2× piperidine CHAHB), 1.78-1.85 (m, 1H, piperidine CH), 2.61 (app d, J=7.1 Hz, 2H, PhCH2), 3.31-3.34 (m, 2H, 2× piperidine NCHAHA), 3.85 (app d, J=11.9 Hz, 2H, 2× piperidine NCHAHA), 4.19 (d, J=7.9 Hz, 2H, CH2—NHBOC), 7.20 (t, J=7.3 Hz, 1H, phenyl H-4), 7.23 (d, J=7.0 Hz, 2H, phenyl H-2 & H-6), 7.31 (t, br, J=7.4 Hz, 2H, phenyl H-3 & H-5), 7.38 (d, J=8.2 Hz, 2H, phenyl H-3′ & H-5′), 7.43 (t, br, J=5.9 Hz, 1H, CH2—NHBOC), 8.11 (d, J=8.9 Hz, 2H, phenyl H-2′ & H-6′), 8.21 (s, 1H, imidazo[4,5-b]pyridine H-5), 13.03 (s, br, 1H, imidazo[4,5-b]pyridine NH);
