The Chemistry of Thiazoles and Dithiocarbamates as Antioxidants

Abstract Using a strictly qualitative approach, the present work suggests a possible explanation for the observed antioxidant action of dithiocarbamates. It has been shown that dithiocarbamates react with hydroperoxides to form a new oxidized intermediate which in most cases is stable. These have been identified as semisulfinates: (see PDF for diagram) With continued oxidation, a normal sulfinate is formed, the structure of which is probably best represented as follows where M is a divalent metal and R is, e.g., a simple alkyl group: (see PDF for diagram) The stability of the above compound will depend upon the metal M and the nature or size of the alkyl group. These compounds further decompose into a thiuram monosulfide and the corresponding metal sulfate. Particularly active or sensitive dithiocarbamates are oxidized directly to the metal sulfate and thiuram monosulfide. In these cases, the ephemeral formation of the semi-sulfinate and normal sulfinate as intermediates is probable. In the presence of excess hydroperoxide, the thiuram monosulfide undergoes further oxidation to form a carbamyl thiocarbamyl disulfide: (see PDF for diagram) Compounds of this structure are moi