Trifluoroacetic acid → 2-(1-(2-(azetidin-3-yl)ethyl)-6-fluoro-1H-indazol-3-yl)-N-tert-butyl-5H-pyrrolo[2,3-b]pyrazine-7-carboxamide

Participants

Reaction Conditions

Reaction Steps

To a pale yellow solution of tert-butyl 3-(2-(3-(7-(tert-butylcarbamoyl)-5-((2-(trimethylsilyl)ethoxy)methyl)-5H-pyrrolo[2,3-b]pyrazin-2-yl)-6-fluoro-1H-indazol-1-yl)ethyl)azetidine-1-carboxylate (43 mg, 64.6 μmol) in dichloromethane (4.00 mL) was added TFA (740 mg, 500 μL, 6.49 mmol00), the reaction mixture turned orange and was stirred at 25° C. for 18 h. The reaction 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 1 h, then evaporated to a yellow solid which was dissolved in dichloromethane (added few drops of MeOH) and purified by chromatography (spherical silica 20-45 μm, 23 g, Versaflash Supelco) eluting with 0 to 10% over 30 min (MeOH containing 10% ammonium hydroxide)/dichloromethane. The pure product dissolved in dichloromethane with few drops of MeOH and cyclohexane added to allow solid formation, off-white solid separated by decantation and dried under high vacuum to give 2-(1-(2-(azetidin-3-yl)ethyl)-6-fluoro-1H-indazol-3-yl)-N-tert-butyl-5H-pyrrolo[2,3-b]pyrazine-7-carboxamide (23 mg, 52.8 μmol, 81.8%). MS (M+H)+=436; 1H NMR (DMSO-d6) δ: 9.08 (s, 1H), 8.48 (dd, J=8.7, 5.3 Hz, 1H), 8.39 (s, 1H), 7.90 (s, 1H), 7.77 (dd, J=9.8, 1.9 Hz, 1H), 7.16 (td, J=9.1, 1.9 Hz, 1H), 4.49 (t, J=6.6 Hz, 2H), 3.68-3.85 (m, 2H), 3.44-3.56 (m, 2H), 2.75 (dt, J=15.2, 7.7 Hz, 1H), 2.20 (q, J=6.7 Hz, 2H), 1.51 (s, 9H).

Provenance & Evidence