[Synthesis]
Step 4: Tert-butyl (1 -(4-(2-(2-(2-aminopyridin-3-yl)-5-phenyl-3H-imidazo[4,5-b]pyridin-3-yl)phenyl)cyclobutyl)carbamate (4.1 g) was dissolved in dichloromethane (100 mL), and a dioxane solution (20 mL) of 4.0 M HCl was slowly added. The reaction mixture was stirred at room temperature for 2.5 hours. After completion of the reaction, ether (50 mL) was added to the suspension and the solid was collected by filtration to afford 3-(3-(4-(1-aminocyclobutyl)phenyl)-5-phenyl-3H-imidazo[4,5-b]pyridin-2-yl)pyridin-2-amine hydrochloride (4.032 g, white solid). The product was characterized by 1H NMR (DMSO-d6, 400 MHz) and LCMS: 1H NMR δ 8.94 (s, 3H), 8.47 (bs, 1H), 8.38 (d, J = 8.8 Hz, 1H), 8.19-8.15 (m, 1H), 8.10-8.03 (m, 3H), 7.93-7.88 (m, 1H), 7.76 (d, J = 8.4 Hz, 1H), 7.69 (d, J = 8.4 Hz, 2H), 7.52-7.40 (m, 3H), 6.92 (t, J = 7.6 Hz, 1H), 2.70-2.57 (m, 4H), 2.29-2.20 (m, 1H), 1.90-1.80 (m, 1H); LCMS: m/z 433 [M + H]+. Calculated elemental analysis (C29H27ON7-3.06HCl-0.01C4H8O2-0.03C4H10O): C 59.61, H 5.28, N 15.36; measured values: C 59.62, H 5.05, N 15.36. |