Desulfurization with Raney Nickel. II. Sulfonamides

Several representative alkyl halides have been condensed with sodium saccharin and the resulting 1,1,3-trioxo-2-alkylbenzo[d]isothiazolines (Ia-f) desulfurized using Raney nickel. Employing common desulfurization methods, the reduction reaction was found to give cyclohexylcarboxamides (e.g., IV) and under very mild conditions, benzamides (Va-e). In comparative alkylation reactions the sodium derivatives of benzenesulfonylbenzamide (IIa), N,N-dibenzenesulfonyloxamide (IIIa) and dibenzenesulfonamide (VIb) were, in general, less satisfactory than sodium saccharin. Reaction between benzenesulfonamide and dimethylformamide in the presence of either benzenesulfonyl chloride, benzoyl chloride, carbobenzoxy chloride, or phosphorus oxychloride was shown to yield N,N-dimethyl-N′-benzenesulfonylformamidine (VII).