Trifluoroacetic acid → N-tert-butyl-2-(5-(difluoromethoxy)-1-methyl-1H-indazol-3-yl)-5H-pyrrolo[2,3-b]pyrazine-7-carboxamide

Participants

Reaction Conditions

Reaction Steps

To a pale yellow solution of N-tert-butyl-2-(5-(difluoromethoxy)-1-methyl-1H-indazol-3-yl)-5-((2-(trimethylsilyl)ethoxy)methyl)-5H-pyrrolo[2,3-b]pyrazine-7-carboxamide (33.4 mg, 61.3 μmol) in dichloromethane (1.44 mL) was added TFA (426 mg, 288 μL, 3.74 mmol, 61 equiv.). The reaction mixture turned orange and was stirred at 25° C. overnight then concentrated. The residue was re-dissolved in 5 mL of a solution of (dichloromethane/MeOH/ammonium hydroxide; 60:10:1) and stirred at 25° C. for 3 h, then evaporated to a light yellow solid, dissolved in dichloromethane (containing a few drops of MeOH) and purified by chromatography (spherical silica 20-45 μm, 23 g, Versaflash Supelco) eluting with 0 to 5% over 15 min (MeOH containing 10% ammonium hydroxide)/dichloromethane. The pure product dissolved in dichloromethane/MeOH and dichloromethane evaporated to allow solid formation, the solid was separated by filtration and dried to give N-tert-butyl-2-(5-(difluoromethoxy)-1-methyl-1H-indazol-3-yl)-5H-pyrrolo[2,3-b]pyrazine-7-carboxamide (23 mg, 55.5 μmol, 90.5%) as an off-white solid. MS (M+H)+=415; 1H NMR (DMSO-d6) δ: 12.80 (br. s., 1H), 9.06 (s, 1H), 8.37 (s, 1H), 8.20 (d, J=1.9 Hz, 1H), 7.85 (d, J=8.7 Hz, 2H), 7.40 (dd, J=8.9, 2.1 Hz, 1H), 7.19 (t, J=74.4 Hz, 1H), 4.19 (s, 3H), 1.49 (s, 9H).

Provenance & Evidence