109-80-8Relevant articles and documents
Photosensitized cleavage of the dithio protecting group by visible light
Epling, Gary A.,Wang, Qingxi
, p. 5909 - 5912 (1992)
Dithio derivatives of aldehydes and ketones have been deprotected under neutral conditions using visible light provided by a 120 Watt spotlight and methylene green as a sensitizer. The key step in the deprotection is apparently an electron transfer from the dithio derivative to the electronically excited visible dye. The resulting dithio radical cation undergoes fragmentation, and the corresponding aldehydes and ketones are isolated in excellent yields.
3-(2-aminophenyl)-4-methyl-1,3-thiazole-2(3H)-thione as an ecofriendly sulphur transfer agent to prepare alkanethiols in high yield and high purity
Mehdid, Mohammed Amine,Djafri, Ayada,Roussel, Christian,Andreoli, Federico
experimental part, p. 4634 - 4643 (2010/04/06)
A new process is described for preparing very pure linear alkanethiols and linear α,ω-alkanedithiols using a sequential alkylation of the title compound, followed by a ring closure to quantitatively give the corresponding 3-methyl[1,3]thiazolo[3,2-a]-[3,1
Reduction of thiokols in the system hydrazine hydrate-base as a new route to alkanedithiols
Alekminskaya,Russavskaya,Korchevin,Deryagina,Trofimov
, p. 732 - 737 (2007/10/03)
A new procedure for preparative synthesis of alkanedithiols from simple commercially available products is based on reduction of the S-S bond in appropriate polyalkylene disulfides (thiokols) in the system hydrazine hydrate-base. Thiokols were prepared by reaction of dihaloalkanes with Na2S2 or K2S2 generated from elemental sulfur and alkali in aqueous hydrazine hydrate. Reaction of 1,2-dibromocyclohexane with sodium or potassium disulfide yields bis(2-bromocyclohexyl) sulfide as the only product.
Reduction of thiocols to alkanepolythiols with benzeneselenol
Shilkina,Papernaya,Deryagina
, p. 263 - 265 (2007/10/03)
Heating of benzeneselenol with polymethylene disulfides to 40-120°C results in formation of the corresponding alkanedithiols or alkanetrithiols and diphenyl diselenide. Poly(tetramethylene disulfide) reacts with benzeneselenol to give 1,2-dithiane and diphenyl diselenide. A radical mechanism of this reaction is discussed.
Synthesis of thiols via palladium catalyzed methanolysis of thioacetates with borohydride exchange resin
Choi,Yoon
, p. 2655 - 2663 (2007/10/02)
Various thiols are prepared quantitatively from the corresponding thioacetates via Pd catalyzed methanolysis with borohydride exchange resin under a mild and neutral conditions. One-pot synthesis of thiols from alkyl halides through the formation of alkyl thioacetates using thioacetate exchange resin followed by methanolysis is also described.
Kinetics of Hydrolysis of 2-Aryl-2-phenyl-1,3-dithianes in 10percent (v/v) Dioxane-Water, Containing Perchloric Acid. Acidity Functions in this Solvent and the Reactivity of α-Thio Carbocations
Ali, Muhammad,Satchell, Derek P. N.,Le, Vu T.
, p. 917 - 922 (2007/10/02)
The acid-catalysed hydrolysis of 2-aryl-2-phenyl-1,3-dithianes in 10percent (v/v) dioxane-water occurs at a convenient rate at 25 deg C in the presence of 5-8 mol dm-3 perchloric acid.The effect on the rate of changes in substituents, acidity and temperature, and of the use of a deuteriated solvent are described.Measurements of the H0 and X acidity functions for the solvent are reported; their values are very similar to those found for pure water over most of the acidity range.The mechanism of hydrolysis is believed to change from an ASE2 scheme for the most reactive dithianes to an A2-like scheme for the least reactive.In very concentrated acid solutions the dithianes (and other suitable S,S-acetals) lead to stoichiometric amounts of the α-thio carbocations often postulated as low-concentration intermediates in S,S-acetal hydrolysis.The kinetics of the reaction of these ions with water to give the benzenophenone (or corresponding carbonyl compound) are described, and compared with findings for similar α-oxo carbocations.Previous views on the mechansim of this reaction are criticised.
Identification of an ASE2 Mechanism in the Hydrolysis of Cyclic Thioacetals
Ali, Muhammad,Satchell, Derek P. N.
, p. 866 - 867 (2007/10/02)
2-Phenyl-2-methyl-1,3-dithiane and its p-methoxy derivative undergo hydrolysis in concentrated aqueous perchloric acid via the ASE2 mechanism rather than via the A1 mechanism.
Degenerate intermolecular thiolate-disulfide interchange involving cyclic five-membered disulfides is faster by ～103 than that involving six- or seven-membered disulfides
Singh, Rajeeva,Whitesides, George M.
, p. 6304 - 6309 (2007/10/02)
The rate constants for degenerate intermolecular thiolate-disulfide interchange involving 1,2-dithiolane (S(CH2)3S) are higher than those involving 1,2-dithiane (S(CH2)4S) by a factor of ～650 in mixtures of DMSO-d6 and D2O. The extrapolated rate constant for 1,2-dithiolane in DMSO-d6 is fast (k ～ 108 M-1 s-1). The rate constants for cyclic six- and seven-membered disulfides are similar to those for acyclic disulfides. Rate constants for self-exchange were measured by dynamic 1H NMR line-shape analysis. The evolutionary selection of lipoamide as the cofactor in 2-oxo acid dehydrogenases may reflect the fast rate of ring opening of the dithiolane ring by nucleophiles.
Acid-Catalyzed Hydrolysis of a (γ-Hydroxyalkyl)ketene Dithioacetal. A Cyclic Intermediate and Product Distribution
Okuyama, Tadashi,Fueno, Takayuki
, p. 1405 - 1408 (2007/10/02)
2-(Hydroxyalkylidene)-1,3-dithiane 1a undergoes acid-catalyzed hydrolysis.Disappearance of 1a is faster than formation of the products thio ester 5a and lactone 5a'.The product distribution changes with pH in a similar way to that of hydrolysis of the cyclic intermediate 3a.Hydrolysis of 1a must proceed mostly through 3a, accompanying its accumulation.In comparison with the reference substrate 1b, anchimeric assistance by the internal hydroxyl group was not observed in wholly aqueous solution, but it becomes apparent in aqueous acetonitrile solutions at high organic concentration.Neighboring hydroxyl participation is considered to occur by internal solvation, and the carbocation 2a can exist as a discrete intermediate of the hydrolysis.
