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

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To a pale yellow solution of N-tert-butyl-2-(5-(difluoromethoxy)-1H-indazol-3-yl)-5-((2-(trimethylsilyl)ethoxy)methyl)-5H-pyrrolo[2,3-b]pyrazine-7-carboxamide (55 mg, 104 μmol) in dichloromethane (3 mL) was added TFA (1.48 g, 1000 μL, 13.0 mmol25), 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 (added few drops MeOH and heating) 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 suspended in dichloromethane and cyclohexane added to complete solid formation, solid was separated by decantation and dried under high vacuum to give N-tert-butyl-2-(5-(difluoromethoxy)-1H-indazol-3-yl)-5H-pyrrolo[2,3-b]pyrazine-7-carboxamide (26 mg, 64.9 μmol, 62.7%) as a white solid. MS (M+H)+=401.1 (100% purity); 1H NMR (DMSO-d6) δ: 9.12 (s, 1H), 8.36 (s, 1H), 8.21 (d, J=2.3 Hz, 1H), 7.88 (s, 1H), 7.72 (d, J=9.1 Hz, 1H), 7.35 (dd, J=9.1, 2.3 Hz, 1H), 7.17 (t, J=74.4 Hz, 1H), 1.50 (s, 9H).

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