Reaction Steps
A solution of N-(2,2-difluoroethyl)-2-(4-(2,4-difluorophenoxyl)piperidin-1-yl)-5-methyl-5,6,7,8-tetrahydropyrido[3,4-b]pyrazin-3-amine TFA salt (15 mg, 0.027 mmol), DIPEA (14.20 μL, 0.081 mmol), and acetic anhydride (3.8 μL, 0.041 mmol) in DCM (271 μL) was stirred at room temperature overnight. Purification by HPLC Method A gave the title compound as a TFA salt (8.9 mg) as an off-white film. 1H NMR (500 MHz, methanol-d4, mixture of rotamers) δ ppm 1.45 (d, J=6.8 Hz, 1.9H), 1.58 (d, J=6.8 Hz, 1.1H), 1.93-2.02 (m, 2H), 2.14 (dd, J=12.7, 3.4 Hz, 2H), 2.19-2.23 (m, 3H), 2.62-2.83 (m, 1.5H), 2.87-3.08 (m, 3.2H), 3.35-3.43 (m, 2H), 3.48-3.55 (m, 0.7H), 3.78 (sxtd, J=14.4, 4.2 Hz, 2H), 4.06 (dd, J=14.2, 5.4 Hz, 0.6H), 4.46 (dt, J=7.6, 3.5, Hz, 1H), 4.73 (dd, J=13.2, 5.4 Hz, 0.4H), 5.34 (q, J=6.8 Hz, 0.6H), 5.92-5.97 (m, 1H), 6.06 (dt, J=9.0, 4.3, Hz, 1H), 6.15-6.20 (m, 1H), 6.86-6.91 (m, 1H), 6.99 (ddd, J=11.2, 8.5, 3.2 Hz, 1H), 7.18 (td, J=9.3, 5.4 Hz, 1H); ESI-MS m/z [M+H]+ 482.
