Redox Activation of Hydrogen Sulfide, Thiols, and Sulfur in Electrosynthesis of Organic Di- and Polysulfides

A novel and efficient method for the synthesis of biologically active organic di-, tri- and tetrasulfides has been proposed. Different methods of redox activation of sulfur, hydrogen sulfide, and thiols in the reactions with organic compounds have been considered. Electrochemical initiation of the reactions of the mediator–H2S–S8 system with cyclohexane, methylcyclohexane, and benzene has occurred to the formation of polysulfides R2Sn (n = 2–4). The application of tetrabutylammonium bromide as a mediator of H2S oxidation has allowed to decrease the anodic overpotential of electrosynthesis. Di- and tetrasulfides have been obtained under anodic activation of the cycloalkanethiols (C5, C6) or thiophenol in the reaction with sulfur. Electroreduction of S8 in the presence of the same thiols has favored the formation of di- and trisulfides. The yield and the ratio of the R5Sn (n = 2–4) depend on the method of redox activation of the thiolating reagent.