Thiocarbamoylation of amine-containing compounds 5. The mechanism of reactions of tetramethylthiuram disulfide with aliphatic amines

Article abstract of DOI:10.1007/BF02494685

Thiocarbamoylation of aliphatic amines with tetramethylthiuram disulfide (TMTD) was studied. The reactions were established to proceed according to a two-stage mechanism. In the first stage, S-(thiocarbamoyl)thiohydroxylamines and dimethyl dithiocarbamates are formed. The latter exist in equilibrium with dimethyldithiocarbamic acid, which can undergo decomposition to give dimethylamine and carbon disulfide. In the second stage, several competitive transformations of these intermediates into the final products occur, viz., (1) the reactions of CS2 with primary amines on heating (70-110 deg C) yield mixed and symmetrical thioureas and the reactions of CS2 with secondary amines give symmetrical dithiocarbamates, and (2) insertion of CS2 into S-(thiocarbamoyl)thiohydroxylamines affords thiuram disulfides. Thiuram disulfides formed from primary amines decompose to give isothiocyanates, which are converted into thioureas by condensation with amines, whereas thiuram disulfides which are obtained in the reactions with secondary amines and which cannot form thioureas react with amines analogously to TMTD.