To a flask charged with 3-chloro-2-(4-(2,4-difluorobenzyl)piperazin-1-yl)pyrido[3,4-b]pyrazine (2.34 g, 6.23 mmol) and potassium fluoride (0.470 g, 8.09 mmol) in DMSO (12 mL) was added DIPEA (2.169 mL, 12.45 mmol) and propan-2-amine (1.605 mL, 18.68 mmol) at 23° C. The reaction was stirred at 23° C. for 22 hr and diluted with water (48 mL) to furnish an orange, oily sludge. The crude product was extracted with EtOAc (25 mL) to furnish a suspension. The resulting solid was filtered, rinsed with EtOAc, and the filtrate was allowed to separate into two layers. The organic phase was washed with brine, dried over Na2SO4, filtered, rinsed with EtOAc, and dried in vacuo. The crude material was dissolved in toluene (5 mL) and purified via medium pressure chromatography using a 20% to 100% gradient eluant of EtOAc in heptane on an NH 60 μM, size 400 column (Shoko Scientific Purif-Pack™) to give the title compound (1.489 g, 60.0%) as a yellow solid. 1H NMR (500 MHz, DMSO-d6) δ ppm 1.24 (d, J=6.4 Hz, 6H), 2.62 (t, J=4.9 Hz, 4H), 3.34-3.41 (m, 4H), 3.59 (s, 2H), 4.22-4.42 (m, 1H), 6.46 (d, J=7.8 Hz, 1H), 7.04-7.17 (m, 1H), 7.22 (td, J=10.0, 2.4 Hz, 1H), 7.40-7.44 (m, 1H), 7.49 (td, J=8.5, 6.8 Hz, 1H), 8.27 (d, J=5.9 Hz, 1H), 8.76 (s, 1H); ESI-MS m/z [M+H]+ 399.0.
