The Preparation of Iminosulfonic Acid Derivatives by Means of Sulfinamides and N-Bromosuccinimide

It has been found that N-substituted benzenesulfinamides (I) react with thionyl chloride to give benzenesulfinyl chloride and the corresponding N-sulfinylamines, and that they are oxidized by treatment with bromine in an alkaline solution to give N-substituted sulfonamides. When these benzenesulfinamides are treated with bromine or N-bromosuccinimide (NBS) in the presence of various primary or secondary amines, the corresponding benzeneiminosulfonamides are obtained in high yields. Similarly, the reaction of I, NBS and sodium p-nitrophenolate or sodium benzoate yields p-nitrophenyl benzeneiminosulfonate or N-benzoylbenzensulfonamide. These reactions are considered to proceed through the benzeneiminosulfonyl bromides formed by the oxidation of sulfinamides with bromine or NBS.