Dimethyl Sulfoxide → 3-[2-Chloro-4-(trifluoromethyl)phenoxy]benzoic acid

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Reaction Steps

To a 300 ml. 3-necked flask fitted with a magnetic stirring bar, condenser, drying tube and thermometer is charged the solid from above, dimethylsulfoxide (100 ml), 3,4-dichlorobenzotrifluoride (21.5 g. 0.10 mole) and anhydrous potassium carbonate (5.0 g) to asure an alkaline pH. The reaction temperature is taken rapidly to 138°-44° C. while vigorous stirring is maintained. After 4 hours a significant conversion is realized and heating is continued overnight (total 22 hrs.). The reaction mixture is then cooled to room temperature and poured into water (1000 ml) and the aqueous reaction mixture extracted with CCl4 (200 ml). The aqueous layer is then decanted and acidified to pHl with concentrated hydrochloric acid. The white solid that precipitated is collected by filtration and vacuum dried at 60° C. overnight to give 27 g of an off-white solid 3-(2-chloro-4-trifluoromethylphenoxy)benzoic acid (85% yield), mp 124°-5° C.

Provenance & Evidence