(2R,4S)-Methyl 2-(2-fluorobenzyl)-4-(3-oxo-2,3-dihydroisoxazol-5-yl)piperidine-1-carboxylate → 5-((2R,4S)-2-(2-fluorobenzyl)piperidin-4-yl)isoxazol-3(2H)-one

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Reaction Steps

(2R,4S)-Methyl 2-(2-fluorobenzyl)-4-(3-oxo-2,3-dihydroisoxazol-5-yl)piperidine-1-carboxylate (492 mg, 1.47 mmol) was stirred in hydrogen bromide (33% in AcOH) overnight (19 h). Evaporation of solvents and purification by preparative HPLC (Instrument: FractionLynx I, Mobilphase: gradient 5-95% MeCN in 0.2% NH3, pH 10, Column: Xbridge Prep C18 5 μm OBD 19*150 mm) yielded 5-((2R,4S)-2-(2-fluorobenzyl)piperidin-4-yl)isoxazol-3(2H)-one (504 mg, 124%). The sample contained DMSO and acetic acid. 1H NMR (400 MHz, cd3od) δ 1.50-1.65 (m, 1H), 1.69-1.84 (m, 1H), 2.08-2.22 (m, 2H), 2.89-3.18 (m, 4H), 3.38-3.51 (m, 2H), 5.66 (s, 1H), 7.11-7.23 (m, 2H), 7.28-7.41 (m, 2H). HRMS Calcd for [C15H17FN2O2+H]+: 277.1352. Found: 277.1344.

Provenance & Evidence