Treatment of aniline (I) with hexafluoroacetone trihydrate (II) and p-toluenesulfonic acid affords derivative (III), which is then derivatized with trifluoroacetic anhydride (IV) to provide trifluoroacetanilide derivative (V). Reduction of (V) by means of LiAlH4 in refluxing THF yields N-trifluoroethylaniline derivative (VI), which is finally converted into the target sulfonamide by reaction with benzenesulfonyl chloride (VII) in pyridine.
The target compound is obtained by sulfonylation of aniline (I) with benzenesulfonyl chloride (II) in MeOH.