Acetic Anhydride → 1-(2-Methoxy-5-trifluoromethylphenyl)ethanone

Participants

Reaction Steps

2′-methoxy-5′-trifluoromethyl-acetophenone was prepared as follow (US2003/0109574): In a water bath at room temperature, to a solution of trifluoromethane sulfonic acid (5 ml, 56.7 mmol) under argon was slowly added a solution of 4-trifluoromethyl-anisol (2.0 g, 11.35 mmol) in acetic anhydride (2.15 ml, 22.7 mmol). The resulting dark mixture was stirred for 3 hours at room temperature then poured onto ice water (26 ml). The product was extracted several times with ether. The ethereal layer was washed with a 10% solution of sodium hydrogenocarbonate, water, dried over sodium sulfate and concentrated to dryness. The residue was purified by flash chromatography over silica gel (gradient cyclohexane/dichloromethane: 0-50%) to yield 2′-methoxy-5′-trifluoromethyl-acetophenone (1.7 g, 67%) as a white solid.

Provenance & Evidence