Trifluoroacetic acid → N-[4-(2-amino-4,4,4-trifluoro-butoxy)-3-(4-chloro-2-methyl-2H-pyrazol-3-yl)-phenyl]-2-fluoro-4-methoxy-benzamide trifluoroacetate

Participants

Reaction Steps

N-(3-(4-chloro-1-methyl-1H-pyrazol-5-yl)-4-hydroxyphenyl)-2-fluoro-4-methoxybenzamide (20.0 mg, 53.2 μmol) was dissolved in anhydrous THF (0.3 mL). Triphenylphosphine (15.4 mg, 58.5 μmol), pre-dissolved in anhydrous THF (0.1 mL) was added to the N-(3-(4-chloro-1-methyl-1H-pyrazol-5-yl)-4-hydroxyphenyl)-2-fluoro-4-methoxybenzamide/THF solution. The reaction was stirred for 5 minutes and then DIAD (16.6 μl, 85.2 μmol), pre-dissolved in anhydrous THF (0.1 mL) was added to the reaction. The mixture was stirred at r.t. for 5 more minutes and then tert-butyl 4,4,4-trifluoro-1-hydroxybutan-2-ylcarbamate (16.2 mg, 66.5 μmol), pre-dissolved in anhydrous THF (0.1 mL) was added. The reaction was then stirred for 4 hours and checked by LC/MS. While the reaction had not gone to completion, pushing the reaction by heating or extending the reaction time did not seem to improve the yield. Thus, the solvent was evaporated, the resulting oil re-suspended in CH2Cl2 (0.5 mL) and TFA (20.5 μl, 266 μmol) was added (to remove the Boc-protecting group from the amine). The reaction was stirred overnight at room temperature. The next day, the solvent was removed and the resulting oil was re-dissolved in DMSO (1 mL). The product was purified by Prep LC/MS (0-50% B, 30 min) to yield N-[4-(2-amino-4,4,4-trifluoro-butoxy)-3-(4-chloro-2-methyl-2H-pyrazol-3-yl)-phenyl]-2-fluoro-4-methoxy-benzamide trifluoroacetate (8.1 mg, 13.0 μmol, 24.5%) as a colorless oil. LCMS m/z 501.3 (M+H); 1H NMR (400 MHz, MeOH-d4) δ ppm 2.48-2.86 (m, 2H), 3.75 (d, J=2.78 Hz, 3H), 3.87-3.97 (m, 1H), 3.89 (s, 3H), 4.10-4.43 (m, 2H), 6.85 (dd, J=12.88, 2.27 Hz, 1H), 6.91 (dd, J=8.72, 2.40 Hz, 1H), 7.30 (dd, J=9.09, 2.27 Hz, 1H), 7.61 (d, J=2.53 Hz, 1H), 7.65-7.69 (m, 1H), 7.76 (t, J=8.59 Hz, 1H), 7.90 (dd, J=8.97, 2.65 Hz, 1H).

Provenance & Evidence