1191-08-8Relevant articles and documents
[FeFe]-Hydrogenase H-Cluster Mimics with Various -S(CH2)nS- Linker Lengths (n = 2-8): A Systematic Study
Abul-Futouh, Hassan,Almazahreh, Laith R.,Harb, Mohammad Kamal,G?rls, Helmar,El-Khateeb, Mohammad,Weigand, Wolfgang
supporting information, p. 10437 - 10451 (2017/09/12)
The effect of the nature of the dithiolato ligand on the physical and electrochemical properties of synthetic H-cluster mimics of the [FeFe]-hydrogenase is still of significant concern. In this report we describe the cyclization of various alkanedithiols to afford cyclic disulfide, tetrasulfide, and hexasulfide compounds. The latter compounds were used as proligands for the synthesis of a series of [FeFe]-hydrogenase H-cluster mimics having the general formulas [Fe2(CO)6{μ-S(CH2)nS}] (n = 4-8), [Fe2(CO)6{μ-S(CH2)nS}]2 (n = 6-8), and [Fe2(CO)6{(μ-S(CH2)nS)2}] (n = 6-8). The resulting complexes were characterized by 1H and 13C{1H} NMR and IR spectroscopic techniques, mass spectrometry, and elemental analysis as well as X-ray analysis. The purpose of this research was to study the influence of the systematic increase of n from 2 to 7 on the redox potentials of the models and the catalytic ability in the presence of acetic acid (AcOH) by applying cyclic voltammetry.
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.
A general and mild synthesis of thioesters and thiols from halides
Zheng, Tu-Cai,Burkart, Maureen,Richardson, David E.
, p. 603 - 606 (2007/10/03)
The conversion of a wide variety of halides to thioesters by reaction with potassium thiocetate under mild conditions is described, and the generality of the method is demonstrated.
THE REDUCTION OF CYCLIC DISULPHIDES WITH TRIARYLPHOSPHINES IN AQUEOUS ORGANIC SOLVENTS
Salim, A.,Tillett, J. G.
, p. 215 - 222 (2007/10/02)
The kinetics of the reduction of cyclic disulphides with triphenylphosphine have been studied in aqueous ethanol at various temperatures.Solvent effects on the reaction of 4-phenyl-1,2-dithiolane with tris-(4-chlorophenyl) phosphine in a number of aqueous organic solvents have been analysed in terms of the Kirkwood, Y and ENT functions.
Predicting the stability of cyclic disulfides by molecular modeling: "Effective concentrations" in thiol-disulfide interchange and the design of strongly reducing dithiols
Burns, John A.,Whitesides, George M.
, p. 6296 - 6303 (2007/10/02)
We have tested molecular mechanics calculations at the level of MM2(85) for their capacity to rationalize relationships between structure and equilibrium constants for thiol-disulfide interchange reactions. With 20 α,ω-dithiols taken from the literature, equilibrium constants for thiol-disulfide interchange with 1,2-dithiane were calculated: HSRSH + S(CH2)4S → SRS + HS(CH2)4SH. The relation between experimental values of ΔG and calculated differences in strain energy was ΔG = 0.41ΔSE + 0.5 kJ/mol with a correlation coefficient of 0.93 (excluding one anomalous point). Results from molecular mechanics correlate well with experimental results, but they cannot give absolute values of energies. Results of molecular mechanics calculations are used to discuss the physical interpretation of the concept of "effective concentration" as it is used for the thiol-disulfide interchange reaction.
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.
Polyfunctional disulfide compounds having S--S exchange reactivity
-
, (2008/06/13)
A polyfunctional disulfide compound, useful as a cross-linking reagent having S--S exchange reactivity, of the formula STR1 wherein R is 2-benzothiazolyl or 2-pyridyl-N-oxide and X is a spacer group having an alkylene group directly bonded to each S--S group.
Rate Constants and Equilibrium Constants for Thiol-Disulphide Interchange Reactions Involving Oxidized Glutathione
Szajewski, Richard P.,Whitesides, George M.
, p. 2011 - 2026 (2007/10/02)
The rate of reduction of oxidized glutathione (GSSG) to glutathione (GSH) by thiolate (RS-) follows a Broensted relation in pKas of the conjugate thiols (RSH): βnuc ca. 0.5.This value is similar to that for reduction of Ellman's reagent: βnuc ca. 0.4 - 0.5.Analysis of a number of rate and equilibrium data, taken both from this work and from the literature, indicates that rate constants, k, for a range of thiolate-disulphide interchange reactions are correlated well by equations of the form log k = C + βnucpKanuc + βcpKac + βlgpKalg ( nuc = nucleophile, c = central, and lg = leaving group sulfur): eq 36 - 38 give representative values of the Broensted coefficients.The values of these Bronsted coefficients are not sharply defined by the available experimental data, although eq 36 - 38 provide useful kinetic models for rates of thiolate-disulfide interchange reactions.The uncertainty in these parameters is such that their detailed mechanistic interpretation is not worthwhile, but their qualitative interpretation - that all three sulphur atoms experience a significant effective negative charge in the transition state, but that the charge is concentrated on the terminal sulfurs - is justified.Equilibrium constants for reduction of GSSG using α,ω-dithiols have been measured.The reducing potential of the dithiol is strongly influenced by the size of the cyclic disulfide formed on its oxidation: the most strongly reducing dithiols are those which can form six-membered cyclic disulfides.Separate equilibrium constants for thiolate anion-disulphide interchange (KS-) and for thiol-disufide interchange (KSH) have been estimated from literature data: KS- is roughly proportional to 2ΔpKa is the difference between the pKas of the two thiols involved in the interchange.The contributions of thiol pKa values to the observed equilibrium constants for reduction of GSSG with α,ω-dithiols appear to be much smaller than those ascribable to the influence of structure on intramolecular ring formation.These equilibrium and rate constants are helpful in choosing dithiols for use as antioxidants in solutions containing proteines: dithiothreitol (DTT), 1,3-dimercapto-2-propanol (DMP), and 2-mercaptoethanol have especially useful properties.
