Thiuram disulfides structures

Captax (Structure 15.21) is used to the extent of 1% with hevea rubber and accounts for the major part of the over 30,000 t of accelerators used annually in the United States. Other accelerators widely used include 2-mercaptobenzothiazole sulfenamide (Santocure Structure 15.22), used for the vulcanization of SBR dithiocarbamates and thiuram disulfides. Thiuram disulfide (Structure 15.23) is a member of a group called ultra-accelerators, which allow the curing of rubber at moderate temperatures and may be used in the absence of sulfur. 

Therapeutic Function Alcohol deterrent Chemical Name Tetraethylthioperoxydicarbonic diamide Common Name Tetraethyl thiuram disulfide Structural Formula ... 

Examples in organometallic systems are known. Reaction of thiuram disulfides, (R2NCS2)2, with Co(Cp)(CO)2 produces dithiocarbamato pseudo-octahedral cobalt(III) complexes Co(Cp)(dtc)2 with one chelated and one monodentate dtc, also accessible via Co(Cp)I(dtc).1050 Fluxional behavior, including monodentate chelate exchange, was observed for some complexes in temperature-dependent NMR studies. The Co(Cp)I(dtc) complex was defined in a crystal structure. 

Since isolable organocopper) 11) compounds do not apparently exist, it is rather surprising that oxidation of the cuprate CdI+[(CF3)2Cu ] (prepared in situ) with thiuram disulfide affords (CF3)2Cu "S2CNEt2 (see Eqn. 1 in Scheme 1.6), the first and so far only example of an organocopper compound with the copper atom in the trivalent oxidation state. The structure of this compound was unambiguously proven by an X-ray crystal structure determination (see Fig. 1.2) [37]. 

Sulfur Donors. MBSS, DPTH, and the thiuram disulfides (see Table 2) are examples. The morpholine disulfide and caprolactam disulfide examples in Table 4 can also donate one atom of sulfur from their molecular structure for cross-linking purposes. Monosulfide cross-links provide better thermal stability than the sulfur—sulfur bonds in di- and polysulfide cross-links, which predominate when elemental sulfur is used. 

To complete these studies, Van Kerckhoven et al. [237] have investigated the behavior of styrene according to two key experiments first, they showed by 13C NMR that when an excess of thiuram disulfide is present, a dicapped structure is effectively obtained ... 

Henderson, et al., 1995). The reaction mechanism for the thiuram disulfide class of oxidizing agents and maleimide class of alkylating agents were examined in our laboratory and are presented below. Thiuram disulfides (Fig. 2, for structures) were examined in detail, since a member of this class... 

While our studies of NC protein alone demonstrated little if any crosslinking, the results with HIV-1 virus showed extensive oligomerization. The mature virion contains a compact ribonucleoprotein complex formed by the genomic RNA and ca. 2,500 copies of the NC protein. Therefor the high concentration of NC in the viral particle the formation of intermolecular disulfide bonds over intramolecular ones is expected to be favored following virus treatment with thiuram disulfides. In agreement with this model, the reaction of tetraethylthiuram disulfide with concentrated samples of HIV-1 NC protein in vitro lead to extensive p7 oligomerization. Such crosslinked macromolecular structures appear likely... 

Previously, the molecular structures of many thiuram di- [20-31] (see Fig. 1), mono- [32], trisulfides [33] and thiuram disulfide derivatives, in which R2NC(S)S- groups are linked by polymethylene chains [34], have been determined by single-crystal X-ray diffraction studies. A number of polycrystalline tetralkylthiuram disulfides and their cyclic analogs have also been recently studied by means of solid-state and CP/MAS NMR [31]. Assignments and and chemical shift data for eight (1-8) selected thiuram disulfide compounds and initial dithiocarbamate salts are shown in Table 1. The observed differences in and isotropic chemical shifts for these molecular systems can be attributed to simultaneous manifestation of the inductive effect of alkyl substituents and to the mesomeric effect of the dithiocarbamate groups discussed below. 

Analogously, NMR spectra exhibit either singlets (Fig. 3a,c) or doublets (Fig. 3b,d,e) for nitrogen sites in the >NC(S)S- groups. However, there is no full correlation between and NMR spectra of thiuram disulfides. For instance, the NMR spectrum of compound 7, R2=(CH2)6 (Table 1) shows a single resonance line for carbon sites in the dithiocarbamate groups (191.7 ppm), while the N NMR spectrum reveals their structural nonequivalence (127.3 and 121.3 ppm. Fig. 3d). Therefore, spectral equivalence of carbon sites can be combined with nonequivalence of peripheral N atoms in the >NC(S)S- groups of thiuram disulfides. 

Hence, four resonance configurations (two for each dithiocarbamate group) should be used for the correct description of thiuram disulfides. The resultant structure is displayed in Scheme 2. 

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