Reaction Steps
A solution of (R)-2-methoxypropanoic acid (1.9 mg, 0.018 mmol), DIPEA (7.0 mg, 0.054 mmol), and HATU (6.9 mg, 0.018 mmol) in DMF (90 μL) was stirred for 10 min at room temperature then treated with N-(2,2-difluoroethyl)-3-(4-(2,4-difluorophenoxyl)piperidin-1-yl)-7-methyl-5,6,7,8-tetrahydropyrido[3,4-b]pyrazin-2-amine TFA salt (10 mg, 0.018 mmol). The resulting reaction mixture was stirred for 2 h. The crude reaction mixture was diluted in DMF, filtered through a hydrophilic PTFE 0.45 μm filter (Millipore® Millex-LCR), and purified via HPLC Method A to give the title compound as a TFA salt (5 mg) as a white solid. 1H NMR (400 MHz, methanol-d4, mixture of rotamers) 6 ppm 1.17 (t, J=6.6 Hz, 1.4H), 1.27 (dd, J=6.7, 2.7 Hz, 1.6H), 1.33 (dd, J=11.6, 6.8 Hz, 1.4H), 1.38 (dd, J=6.7, 2.7 Hz, 1.6H), 1.92-2.03 (m, 2H), 2.09-2.18 (m, 2H), 2.53-2.68 (m, 1H), 2.94-3.05 (m, 2H), 3.08-3.10 (m, 0.5H), 3.12-3.14 (m, 0.5H), 3.35 (s, 3H), 3.37-3.42 (m, 2H), 3.78 (td, J=14.5, 4.2 Hz, 2H), 4.03 (t, J=18.8 Hz, 1H), 4.30-4.41 (m, 1H), 4.43-4.51 (m, 1H), 4.70-4.82 (m, 1H), 5.03-5.14 (m, 0.5H), 5.18-5.23 (m, 0.5H), 5.90-6.22 (m, 1H), 6.85-6.91 (m, 1H), 6.99 (ddd, J=11.3, 8.5, 2.9 Hz, 1H), 7.18 (td, J=9.2, 5.4 Hz, 1H); ESI-MS m/z [M+H]+ 525.9.
