Trifluoroacetic acid → N-tert-butyl-2-(1-methyl-4,5,6,7-tetrahydro-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-(1-methyl-4,5,6,7-tetrahydro-1H-indazol-3-yl)-5-((2-(trimethylsilyl)ethoxy)methyl)-5H-pyrrolo[2,3-b]pyrazine-7-carboxamide (25 mg, 51.8 mmol) in dichloromethane (2.00 mL) was added TFA (2.96 g, 2.00 mL, 26.0 mmol, Eq: 501), the reaction mixture turned brown and was stirred at 25° C. for 18 h. The mixture was concentrated and 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. Product isolated as an off-white solid which was sonicated with cyclohexane decanted and then sonicated again with MeOH, decanted and dried to give clean N-tert-butyl-2-(1-methyl-4,5,6,7-tetrahydro-1H-indazol-3-yl)-5H-pyrrolo[2,3-b]pyrazine-7-carboxamide (8 mg, 22.7 μmol, 43.8%). MS (M+H)+=353.1; 1H NMR (DMSO-d6) δ: 8.91 (s, 1H), 8.26 (s, 1H), 7.74 (s, 1H), 3.76 (s, 3H), 2.91 (br. s., 2H), 2.64 (br. s., 2H), 1.65-1.84 (m, 4H), 1.45 (s, 9H); LCMS ESI+ TIC MS showed 100% purity, [M+H]+=353.1, [MNa]+=375.0.

Provenance & Evidence