- Cleavage of S-S bond by nitric oxide (NO) in the presence of oxygen: A disproportionation reaction of two disulfides
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Disulfide bond was cleaved by a catalytic amount of nitric oxide in the presence of oxygen, which was confirmed by experiments employing two symmetrical disulfides. The reaction resulted in the formation of unsymmetrical disulfides in nearly 50% yields. The steric hindrance of alkyl disulfide slowed the reaction rate, and an electron-donating group on the aryl disulfide promoted the reaction. The substituent and S-nitrosothiol effects suggested that the reaction was initialized with an oxidative process by NO+.
- Tsutsumi,Itoh,Ohsawa
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p. 1524 - 1528
(2007/10/03)
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- Electro-organic Reactions. Part 24. Preparative and Mechanistic Aspects of the Anodic Oxidation of Dithioacetals and 1,3-Dithianes
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Anodic oxidation of the title compounds is a convenient and efficient method for deprotection, i.e. for the regeneration of carbonyl compounds. A detailed investigation of sulphur-containing products confirmed that the initial, 2 F mol-1, products are disulphides which, in aqueous acetonitrile, are oxidised further to alkyl alkane thiosulphinates and the corresponding thiosulphonates.In some cases alkyl polysulphides and N-alkylacetamides are important products.Unsymmetrical dithioacetals are oxidised anodically to the three possible disulphides, i.e. cross-coupling occurs.Unsymmetrical disulphides are similarly oxidised to a complex mixture of symmetrical and unsymmetrical thiosulphinates and thiosulphonates. These results, combined with those of cyclic voltammetric and coulometric experiments, suggest a mechanism in which the key step in carbon-sulphur bond cleavage in the initially formed radical cation.The direction of the cleavage is determined by understandable substituent effects.
- Porter, Quentin N.,Utley, James H. P.,Machion, Pedro D.,Pardini, Vera L.,Schumacher, Paolo R.,Viertler, Hans
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p. 973 - 979
(2007/10/02)
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- REACTION OF THIOLSULFINATES WITH TRIHALOACETIC ANHYDRIDES-I EVIDENCE FOR THE FORMATION OF SULFENYL AND SULFINYL CARBOXYLATES
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Thiosulfinates react with trifluoro- or trichloroacetic anhydride to give equimolar mixtures of the coresponding disulfides and sulfinyl trifluoro- or trichloroacetates which are in equilibria with sulfenyl carboxylates.Although the equilibrium lies far toward sulfinyl carboxylates at room temperature, addition of olefins to the mixed solution of sulfinyl carboxylate and corresponding disulfide affords the adducts which are formed in the reaction between the corresponding sulfenyl carboxylates and the olefins.Meanwhile, treatment of carboxylic acid silver salts with sulfinyl chlorides also gives sulfinyl carboxylates, howevver, sulfinyl carboxylates have not been successfully isolated yet.
- Morishita, Tsuyoshy,Furukawa, Naomichi,Oae, Shigeru
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p. 3115 - 3120
(2007/10/02)
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