Bis disulfide, formation

Scheme 10 Bis-disulfide Formation with Air Oxygen and Iodine...

Scheme 11 Bis-disulfide Formation with Dimethyl Sulfoxide and Thallium(III) Trifluoroacetate1 071...

Scheme 12 Bis-disulfide Formation with Iodine and Chlorosilane/Sulfoxide1 241...

Scheme 13 Bis-disulfide Formation by Air Oxygen and Dimethyl Sulfoxide/Acid1521...

Scheme 14 Solid-Phase Bis-disulfide Formation with Carbon Tetrachloride and Thallium(III)I1071 Tmb Acm Tmb Acm...

Bloxham, D.P., and Cooper, C.K. (1982) Formation of a polymethylene bis(disulfide) inter-subunit crosslink between cys-281 residues in rabbit muscle glyceraldehyde-3-phosphate dehydrogenase using octamethylene bzs-(methane[35]thiosulfonate). Biochemistry 21, 1807. 

The formation of a single product from zinc distillation and only one disulfonic acid by oxidation would follow if cassipourine were a bis-(disulfide) with the two halves symmetrically substituted, and a 1,2-structure was envisaged as the most rational. The X-ray analysis of a... 

Disulfide Formation in Polystyrene Networks. Polymer-bound thiols were prepared by copolymerizations of bis -vinylbenzyl)disulfide with other divinyl monomers followed by diborane reduction (Scheme 5) (fiS). The initially formed thiols were juxtaposed for reoxidation to disulfides. Polymer-bound thiols were prepared also by copolymerization of p-vinylbentyl thiolacetate with divinyl monomers followed by hydrolysis (Scheme 6). llie latter thiols were distributed randomly throughout the polymer network. The copolymer reactivity ratios for p-vinylbenzyl thiolacetate and styrene are unknown, but should be similar to those of styrene (Mi) and p-vinyl-bentyl chloride (M2) ri = 0.6, r2 = 1.1 (fifi). Copolymeiizations with equal volumes of monomers and 1/1 acetonitrile/toluene product macroporous 40-48% DVB-cross-linked networks (651. 

Dithiothymidine (98) has been prepared as outlined in Scheme 12. The dimesylate 97 could be converted into the rAreo-bis(disulfide) 99, but all attempts to isolate the rAreo-dithiol led to the formation of the cyclic disulfide 100, even though the dithiol could be trapped as an isopropylidene derivative. ... 

The synthesis of poly(arylene sulfide)s via the thermolysis of bis(4-iodophenyl) disulfide has been reported (78). The process leads to the formation of PPS and elemental iodine. This process presumably occurs analogously to that reported by Eastman Chemical Company. 

The KF-S reaction presumably involves attack of a fluonnated caibanion on sulfur, whereas the S-Sbp5 reaction may involve electrophilic attack by a cationic sulfur species on the olefin under the strong Lewis acid conditions Electrophilic attack on a fluonnated olefin may also account for formation of a perfluorinated sulfide from reaction of bis(pentafluorophenyl)disulfide with hexafluoropropylene under superacid conditions [IS5] (equation 28)... 

The asymmetrical anhydrobase (20) constitutes the first step of the formation of trimethine thiazolocyanine when a 2-methylthiazolium salt reacts either with a benzothiazolium or its opened form [which is bis-o-(formylmethylamino)(diphenyl disulfide] (Scheme 26). In a second step, 20 is protonated by a second molecule of 2-methylthiazolium. It results in cleavage of the benzothiazoline ring, which gives 21 together with the formation of the monomeric anhydrobase (22). Cleavage of the C-S bond of 20 can be explained by the important electronic desaturation of the C atom observed in NMR spectrum and the great polarizability of the C-S bond in this type of ring (48). 

Dining preparation of thiophenol by addition of a cold solution of potassium O-methyldithiocarbonate to a cold solution of benzenediazonium chloride, a violent explosion accompanied by an orange flash occurred [1], This was attributed to the formation and decomposition of bis(benzenediazo) disulfide. A preparation in which the diazonium solution was added to the xanthate solution proceeded smoothly [2],... 

A novel synthesis of alkylsulfanylisothiazoles 230 starts with sodium a-cyanoketene dithiolates 227, obtained by the reaction of cyanoacetamides 226 with carbon disulfide in the presence of sodium ethoxide <06SC825>. Treatment of 227 with sulphur and piperidine acetate generates sodium isothiazole-3,5-dithiolates 229. The formation of 229 is assumed to arise from the addition of anionic sulphur to the nitrile group in 227 to give the intermediate 228, which cyclizes upon elimination of anionic sulphur to yield 229. Salts 229 are readily alkylated to furnish 3,5-bis(alkylthio)isothiazole derivatives 230. 

Decomposition of highly reactive disulfonium dications in sufficiently nucleophilic medium is accompanied by formation of disulfides. Even hydrolysis of disulfonium dications generated from sterically rigid bis-sulfides often affords some disulfide as a by-product in addition to the monosulfoxide main product. For example, hydrolysis of dication 72 yields sulfoxide 74 and trace amounts of heterocycle 73 (Scheme 28).56... 

An unusual seven-membered diazaphosphatetrathia heterocycle (190) containing a chain of four sulfur atoms was obtained using diaryl or dialkyl phenyl phosphonamide 187 with sulfur monochloride in the presence of pyridine base (1993CC1684). A mechanism of the formation of 190 remains unclear but 190 was possibly formed via expected disulfide 188 which might be in equilibrium with bis(thionitroxide) 189 and the latter, in turn, could then further react with S2CI2 (Scheme 94). The extension sulfur chain was explained by the S2CI2 addition and... 

Little is known of the biological and chemical behavior of the fluorodichloromethyl derivatives. Rio-tolysis of dichlofluanid results in the formation of N,N-dimethyl-N -phenylsulphamide, phenyl isocyanate and isothiocyanates and dimethylamidosulfonyl chloride GC-MS analysis also indicates the presence of bis-(fluorodichloromethyl) disulfide and two ketones, the latter being artifacts arising from the solvent, acetone. Dichlofluanid metabolism in plants yields N,N-dimethyl-N -phenylsulphamide (1 6), but nothing is... 

The proposed metabolic pathway in strawberries is shown in Figure 3. Five compounds mixed disulfide, sulfide, sulfenic acid, thiophosgene and the GSH-re-action product have not been identified as a strawberry metabolite but their involvement is very likely based on the formation of bis-(fluorodichloromethyl)... 

The iodine oxidation method has also been applied in one-pot synthetic strategies to mono-disulfide peptides in which the bis-cysteine peptide is cleaved from the resin, depro-tected, and oxidized in a single step.163 64 A comparative analysis of the iodine procedure (TFA/10 equiv I2) with other TFA/oxidant mixtures using oxytocin as the target model peptide clearly revealed formation of side products to a significant extent. 85 ... 

---