Potassium peroxymonosulphate → 4-[3,5-Difluoro-4-(methylsulfonyl)-phenyl]-5-methyl-3-phenylisoxazole

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Reaction Steps

Potassium peroxymonosulfate (0.25 g, 0.40 mmol) and water (7 mL) were added to a mixture of 4-[3,5-difluoro-4-(methyl-sulfinyl)phenyl]-5-methyl-3-phenylisoxazole (0.10 g, 0.30 mmol), dichloromethane (4 mL), and methanol (4 mL). The mixture was stirred for four days at room temperature. To the mixture was added magnesium monoperoxyphathalate hexahydrate (0.50 g, 0.80 mmol), dichloromethane (20 mL), methanol (10 mL). The mixture was stirred vigorously for 18 hours. To the mixture was added potassium peroxymonosulfate (0.35 g, 0.57 mmol), and the reaction continued for 18 hours. The mixture was poured into water and extracted with dichloromethane (4×75 mL). The combined extracts were dried with magnesium sulfate, concentrated, and the residue purified by silica gel chromatography using 30% ethyl acetate in hexanes. A white solid (98 mg, 93%) was obtained. MP 140.4-143.4° C. 1H NMR (CDCl3/400 MHz) 7.35-7.45 (m, 5H), 6.84 (d, 2H, J=9.4), 3.32 (s, 3H) 2.52 (s, 3H). ESHRMS m/z 350.0642 (M+H+, Calcd 350.0662).

Provenance & Evidence