Dimethyl Sulfoxide → 4-Chloro-2-(trifluoromethyl)phenol

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Reaction Steps

To a 300 ml, 3-necked flask fitted with a stirrer, condenser, thermometer and drying tube is added dimethylsulfoxide (100 ml), tert-butanol (20 ml), powdered potassium hydroxide (KOH) pellets (85%, 30 g) and 2,5-dichlorobenzotrifluoride (21.5 g, 0.10 mole). The reaction mixture is warmed to 71°-73° C. for 60 hours, then additional KOH (10 g) is added and heating is continued at 73°-75° C. for 24 hours. The reaction mixture is cooled and the solvent partially removed by distillation at 0.9 mm, bp 55° C.). The cooled pot residue is then poured into ice water (1000 g) which had been preacidified to pH 1 with conc. HCl (50 ml). The aqueous mixture is extracted with carbon tetrachloride (CCl4), the CCl4 layer decanted and dried and the solvent removed under vacuum to afford 10.8 g of 4-chloro-2-trifluoromethylphenol, which is sublimed to afford pure product, mp 81° -81.5° C. Elemental Anal. Calcd for C7H4ClF3O: C, 42.75; H, 2.06; Cl, 18.04: Found: C, 42.54; H, 2.36; Cl, 18.16. ##STR10##

Provenance & Evidence