Reaction Steps
A solution of N-(2,2-difluoroethyl)-3-(4-(2,4-difluorophenoxyl)piperidin-1-yl)-5,6,7,8-tetrahydropyrido[3,4-b]pyrazin-2-amine TFA salt (17 mg, 0.032 mmol), DIPEA (12.2 mg, 0.095 mmol), and HATU (13.2 mg, 0.035 mmol) in DMF (158 μL) was stirred for 10 min at rt. To this was added (R)-2-methoxypropanoic acid (3.6 mg, 0.035 mmol), and the resulting reaction mixture stirred overnight. 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 (6 mg) as a clear oil. 1H NMR (400 MHz, methanol-d4, mixture of rotamers) δ ppm 1.32 (d, J=6.8 Hz, 1.3H), 1.38 (d, J=6.6 Hz, 1.7H), 1.92-2.03 (m, 2H), 2.09-2.18 (m, 2H), 2.78 (t, J=6.2 Hz, 0.9H), 2.86 (m, 1.1H), 2.97-3.06 (m, 2H), 3.33 (s, 3H), 3.35-3.43 (m, 2H), 3.79 (td, J=14.5, 4.3 Hz, 2H), 3.85-3.97 (m, 2H), 4.36 (dq, J=12.7, 6.5 Hz, 1H), 4.42-4.49 (m, 1H), 4.58 (m, 0.9H), 4.68 (m, 1.1H), 5.90-6.22 (m, 1H), 6.84-6.91 (m, 1H), 6.98 (ddd, J=11.4, 8.5, 3.0 Hz, 1H), 7.18 (td, J=9.2, 5.3 Hz, 1H); ESI-MS m/z [M+H]+ 512.4.
