2,2,2-Trifluoroethanol → 3-(2,2,2-Trifluoroethoxy)phenoxathiin 10,10-dioxide

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Reaction Steps

1,1,1-Trifluoro-2-ethanol (Aldrich) (0.44 g, 0.004 mole) was added to a stirred, ice-bath cooled mixture of potassium hydride (approximate 50% dispersion in mineral oil) (Aldrich) (0.32 g, 0.004 mole) and N,N-dimethylformamide (75 mL). The ice-bath was removed, and the reaction was stirred at ambient temperature for 1 hour. 3-Fluorophenoxathiin 10,10-dioxide (Example 47) (1.00 g, 0.004 mole) was added, and the mixture was heated at reflux under nitrogen for 2 hours. The reaction was cooled, and the volatiles were removed by spin evaporation in vacuo. The residue was purified by column chromatography on Silica Gel 60 using ethyl acetate-hexanes:2-8. The appropriate column fractions were combined, and the volatiles were removed by spin evaporation in vacuo to give 0.43 g (32% yield) of 3-(2,2,2-trifluoroethoxy)phenoxathiin 10,10-dioxide. Recrystallization from ethanol gave 0.23 g (17% yield) of 3-(2,2,2-trifluoroethoxy)phenoxathiin 10,10-dioxide, m.p. 165-166° C.

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