Acetic Anhydride → HCID 118159271, compound

Participants

Reaction Conditions

Reaction Steps

To a pressure reactor charged with a red-orange solution of tert-butyl 4-(3-(isopropylamino)pyrido[3,4-b]pyrazin-2-yl)piperazine-1-carboxylate (2.0 g, 5.37 mmol) in acetone (100 mL) and dioxane (100 mL) was added palladium, 10 wt % on activated carbon (0.229 g, 2.148 mmol) as a slurry in dioxane (3 mL) under nitrogen. Next, acetic anhydride (5.04 mL, 53.7 mmol) was added at 23° C. The mixture was stirred under hydrogen at 310 kPa for 17 hr at 45° C. The reaction mixture was filtered through Celite™, rinsed with dioxane, and concentrated via rotary evaporation. The crude material was purified via medium pressure chromatography using 10% to 100% gradient of EtOAc in heptane on an NH 60 μM size 400 column (Shoko Scientific Purif-Pack™) to give the title compound (1.068 g, 47.5%) as a yellow foam. 1H NMR (500 MHz, DMSO-d6, mixture of rotamers) 6 ppm 1.16-1.21 (m, 6H), 1.42 (s, 9H), 2.08 (s, 1.3H), 2.09 (s, 1.7H), 2.58 (t, J=5.9 Hz, 0.9H), 2.70 (t, J=5.6 Hz, 1.1H), 2.87-2.98 (m, 4H), 3.51 (br s, 4H), 3.67-3.75 (m, 2H), 4.06-4.15 (m, 1H), 4.41 (s, 1.1H), 4.44 (s, 0.9H), 5.50 (d, J=7.8 Hz, 1H), 5.53 (d, J=7.8 Hz, 1H); ESI-MS m/z [M+H]+ 419.0.

Provenance & Evidence