Reaction Steps
(S)-N-(4-(3-aminopiperidin-1-yl)pyridin-3-yl)-6-(2,6-difluorophenyl)-[1,2,4]triazolo[4,3-b]pyridazin-3-amine 2,2,2-trifluoroacetate (Example 67) and (S)-N-(4-(3-aminopiperidin-1-yl)pyridin-3-yl)-[1,2,4]triazolo[4,3-a]pyridin-3-amine 2,2,2-trifluoroacetate (Example 68). A glass microwave reaction vessel was charged with (S)-tert-butyl (1-(3-((6-chloro-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)amino)pyridin-4-yl)piperidin-3-yl)carbamate (175 mg, 0.39 mmol) and 2,6-difluorophenylzinc bromide (0.5 M in THF, 2.36 mL, 1.18 mmol, Rieke Metals, Inc.) followed by A-Phos (14 mg, 0.020 mmol, Sigma-Aldrich). The reaction mixture was stirred and heated at 90° C. for 2 h. The mixture was cooled to RT and quenched with EDTA solution (pH 7.4) and extracted with CHCl3/i-PrOH (4/1). The combined organic layers were dried over MgSO4, filtered and concentrated to give (S)-tert-butyl (1-(3-((6-(2,6-difluorophenyl)-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)amino)pyridin-4-yl)piperidin-3-yl)carbamate (206 mg), which was used in the next reaction without further purification. A mixture of (S)-tert-butyl (1-(3-((6-(2,6-difluorophenyl)-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)amino)pyridin-4-yl)piperidin-3-yl)carbamate (206 mg, 0.39 mmol) and TFA (0.2 mL, 2.69 mmol) in DCM (1 mL) was stirred for 15 min at RT. The mixture was concentrated and the residue was purified with prep HPLC (5-30% MeCN in water with 0.1% TFA for 30 min) using Phenomenex Gemini C18 column (100×50 mm, 10 μm) at 90 mL/min. with UV detection at 254 nm to give (S)-N-(4-(3-aminopiperidin-1-yl)pyridin-3-yl)-6-(2,6-difluorophenyl)-[1,2,4]triazolo[4,3-b]pyridazin-3-amine 2,2,2-trifluoroacetate (70 mg, 0.13 mmol, 33% yield, Example 67) as a yellow solid. MS (ESI, pos. ion) m/z: 422.9 (M+1). 1H NMR (400 MHz, DMSO-d6) δ ppm 9.24 (1 H, br. s.), 8.84 (1 H, s), 8.45 (1 H, d, J=9.6 Hz), 8.39 (1 H, d, J=6.5 Hz), 8.02 (3 H, br. s.), 7.67-7.77 (1 H, m), 7.53 (1 H, d, J=9.8 Hz), 7.33-7.44 (3 H, m), 3.82 (1 H, d, J=12.5 Hz), 3.30-3.38 (3 H, m), 3.21 (1 H, dd, J=11.8, 6.9 Hz), 1.93 (1 H, dd, J=8.2, 4.1 Hz), 1.73-1.85 (1 H, m), 1.61-1.71 (1 H, m), 1.41-1.53 (1 H, m). 19F NMR (376 MHz, DMSO-d6) δ ppm −74.04, −113.49; and (S)-N-(4-(3-aminopiperidin-1-yl)pyridin-3-yl)-[1,2,4]triazolo[4,3-a]pyridin-3-amine 2,2,2-trifluoroacetate (27 mg, 0.09 mmol, Example 68) as a light yellow solid. MS (ESI, pos. ion) m/z: 311.1 (M+1). 1H NMR (400 MHz, DMSO-d6) δ ppm 9.22 (1 H, s), 8.36 (1 H, d, J=6.5 Hz), 8.09 (3 H, br. s.), 7.43 (1 H, d, J=6.5 Hz), 7.24 (1 H, d, J=11.7 Hz), 5.92-6.13 (1 H, m), 3.76 (1 H, d, J=12.5 Hz), 3.43-3.59 (1 H, m), 2.99-3.30 (3 H, m), 1.88-2.04 (2 H, m), 1.54-1.78 (2 H, m).
