Russhm Chemical Bulletin, ~bl. 49. A')). 2, February, 2000 335 Thiocarbamoylation of amine-containing compounds 5.* The mechanism of reactions of tetramethylthiuram disulfide with aliphatic amines Luu Van Boi N. D. Zefinsky Institute o/ O~anic Chemist~, Russian Academy of Sciences, 47 Leninsky prosp., I 17913 Moscow, Russian Federation. Fax: +7 (095) I35 532S. E-mail: mnn@cacr.ioc.ac.ru Thiocalbamoylation 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-(thiocarbamoyt)thiohydroxylamines and dimcthy~ dithiocarbamates are formed. The lauer exist in equilibrium with dimcthyldithiocarbamic acid, which can undergo decomposition to give dimethylamine and ca~on disulfide. In the second stage, several competitive transformations of these intermediates into the final products occur, vi~., (l) the reactions of CS~ with primal' amines on heating (70--110 ~ yield mixed and symmetrical dm)ttreas and tt{e reactions of CS, with secondary amines give symmetrical dithiocarbamates. and (2) insertion of CS~ into 5"-(thiocamamoyl)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 distdfides which are obtained in the reactions with secondary amines and which cannot form thioureas react with amines analogously to TMTD. Key words: tetramethylthiuram disulfide, aliphatic anaines, dialkyl(cycloalkyl)ammonium diatkyl(cycloalkyl)dithiocarbamates. S-( N,3i-dimethylthioca rbamoyl)-.V-alkyl(dialkyl)- t,cycloaekyl)thiohydroxyLamines, mixed N'-alkyI(dialkyl)(cycloalkyl~-N,N-dimethylthiuram di- sulfides, dialkyl(.dicycloatkyl)thioureas, benzyl and cyclohexyl i~othiocyanates. Previously, we have demonstrated z-It that oile of the best procedures for the introduction of the thiocarbonyl group into organic compounds invobes the reactions of tetramethylthiuram disulfide (TMTD) with amines, which had been poorly studied. We have estab- lished I that primau amines (la,b) react with TM'I'D at temperatures below 110 ~ to lbrm mixtures containing mixed (2a,b) and symmetrical (3a,b) thiot, reas, while secondary amines (le--e) give mixtures of dialkyl(cyclo- alkyl)ammonium dimethyldithiocarbamates (4a,b) and "symmetrical" dialkyl(cycloalkyl)ammonium dialkyl- (cycloalkyl)dithiocarbamates (Sere) with the latter pre- dominating (Scheme l). The present work is devoted to studies of the charac- ter of the processes resulting in these products. Hypothetical schemes of the reactions of TMTD with amines have been proposed previously. It was suggested t2 that TMTD initially decomposes to give sulfur and tetramethylthiumn~ monosulfide, which unde~oes nu- cleophilic replacement with amines to form one mole of substituted thiourea and dimethyldithiocarbamic acid. The latter reacts with amines yielding the same thiourea with elimination of H~S tz (Scheme 2). This scheme cannot explain many facts observed by us, for example, the formation of symmetrical thioureas * For Part 4, set Ref. 1. Scheme 1 S S I( H R~R2NH + Me2NCSSCNMe 2 I a--e I (TMTD) I S S II Me2N~, ~ H2i~l R, R 2 Me2NCNHR2 2a,b 4c,d + + S S II IP- R2NHCNHR 2 R1R2NCS H21"4R~ R2 3a,b 5c--e R ~ = H, R 2 = C6H~ (a);gl ~ = H, R 2 = PhCH 2 (b); R I + R 2 = (CH2)20(CH2) z (c): R ~ ~- R 2 = (CH2) s (d); R 1 = R 2 = Me (e) 3a,b, which were detected among the products of the reactions of TMTD with primary amines la,b. Based on the results of the synthesis and kinetic studies, a radical-ionic mechanism of the reactions of TMTD with aliphatic amines 1 was suggested. 13,14 At 20 ~ these reactions afford S-(N,N-dimethyhhio- carbamoyl)thiohydroxylamines (6) and dimethyldithio- carbamic acid (7!, which reacts with amines 1 to give the Translated from lzvevti.va Akademii Nauk. Ser~va Khbnicheskaya, No. 2. pp. 334--342, Februar}. 2000. 1066-5285/00/4902-0335 $2500 <~)2001) Kluv,er Academic/Plenmn Pub{ishers