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

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Reaction Steps

(2S,4R)-Methyl 2-(2,4-difluorobenzyl)-4-(3-oxo-2,3-dihydroisoxazol-5-yl)piperidine-1-carboxylate 367 mg, 1.04 mmol) (from example 134, step 3) was dissolved in hydrogen bromide (33% in acetic acid, 8.2 mL, 46.87 mmol) and stirred at room temperature for 16 h. The solvent was removed in vacuo and the residue purified by preparative HPLC (Instrument: FractionLynx III, Mobilphase: gradient 5-95% MeCN in 0.2% NH3, pH 10, Column: Xbridge Prep C18 5 μm OBD 19*150 mm) to yield 5-((2S,4R)-2-(2,4-difluorobenzyl)piperidin-4-yl)isoxazol-3(2H)-one (144 mg, 47%). 1H NMR (400 MHz, cd3od) δ 1.43 (q, 1H), 1.67 (dq, 1H), 2.01-2.11 (m, 2H), 2.79-2.96 (m, 4H), 3.14-3.23 (m, 1H), 3.27-3.35 (m, 1H), 5.52 (s, 1H), 6.92-7.01 (m, 2H), 7.28-7.35 (m, 1H). HRMS Calculated for [C15H16F2N2O2+H]+: 295.1258. Found: 295.1259

Provenance & Evidence