Hydrogen Bromide → 5-((2R,4S)-2-(3,5-difluoro-4-(trifluoromethyl)phenyl)piperidin-4-yl)isoxazol-3(2H)-one

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Reaction Steps

(2R,4S)-Methyl 2-(3,5-difluoro-4-(trifluoromethyl)phenyl)-4-(3-oxo-2,3-dihydroisoxazol-5-yl)piperidine-1-carboxylate (226 mg, 0.56 mmol) was dissolved in hydrobromic acid (33% in AcOH, 5 mL, 30.38 mmol) and stirred at room temperature for 20 h. The solvent was evaporated and the residue purified by preparative HPLC (Instrument: FractionLynx II, Mobilphase: gradient 5-95% MeCN in 0.2% NH3, pH 10, Column: Xbridge Prep C18 5 μm OBD 19*150 mm) to yield 5-((2R,4S)-2-(3,5-difluoro-4-(trifluoromethyl)phenyl)piperidin-4-yl)isoxazol-3(2H)-one (133 mg, 68%). 1H NMR (600 MHz, dmso) δ 1.30 (q, 1H), 1.43 (dq, 1H), 1.84-1.89 (m, 1H), 2.02-2.07 (m, 1H), 2.70 (dt, 1H), 2.86 (tt, 1H), 3.07-3.13 (m, 1H), 3.75 (dd, 1H), 5.73 (s, 1H), 7.37 (d, 2H). HRMS Calcd for [C15H13F5N2O2+H]+: 349.0975. Found: 349.0972.

Provenance & Evidence