Trifluoroacetic anhydride → 3-[5-(3,4-Dimethoxy-5-nitro-phenyl)-pyrazol-1-yl]-2-trifluoromethyl-pyridine 1-oxide

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Reaction Steps

To a solution of 3-[5-(3,4-dimethoxy-5-nitro-phenyl)-pyrazol-1-yl]-2-trifluoromethyl-pyridine (0.50 g, 1.27 mmol) in dichloromethane (10 mL) cooled in an ice-water bath was added urea-hydrogen peroxide complex (0.26 g, 2.76 mmol) in one portion followed by trifluoroacetic anhydride (0.53 g, 2.52 mmol) dropwise. The resulting mixture was allowed to stir at room temperature overnight and then the insoluble material was filtered off. The filtrate was washed with water and brine, then dried over anhydrous sodium sulphate, filtered and evaporated to leave an off-white solid. Recrystallisation from ethanol afforded 3-[5-(3,4-dimethoxy-5-nitro-phenyl)-pyrazol-1-yl]-2-trifluoromethyl-pyridine 1-oxide, 0.34 g (65%).

Provenance & Evidence