- Vis/NIR light driven mild and clean synthesis of disulfides in the presence of Cu2(OH)PO4 under aerobic conditions
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A highly efficient one-pot strategy has been developed for the synthesis of disulfide in the presence of air under the irradiation of Vis/NIR light. Copper hydroxyphosphate (CHP) Cu2(OH)PO4, has been used as a Vis/NIR active photocatalyst. Disulfide forms on the surface of the catalyst by a radical mechanism. The protocol is useful for solvent free disulfide synthesis from a variety of thiols. This journal is
- Shah, Sk. Sheriff,Karthik,Singh, N. D. Pradeep
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- Design and fabrication of dual-targeted delivery system based on gemcitabine-conjugated human serum albumin nanoparticles
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Dual-targeted drug delivery system has established their reputation as potent vehicles for cancer chemotherapies. Herein, gemcitabine (Gem) was conjugated to human serum albumin (HSA) via dithiodipropionic anhydride to fabricate Gem-HSA nanoparticles. It was hypothesized that this system can enhance the low stability of Gem and can improve its intracellular delivery. Furthermore, folate was applied as targeting agent on HSA nanoparticles for increasing the tumor selectivity of Gem. To evaluate the structural properties of synthesized products, 1H NMR and FT-IR were performed. Moreover, HPLC was implemented for confirming the conjugation between HSA and Gem. Nanoparticles have shown spherical shape with negative charge. The release rate of Gem was dependent to the concentration of glutathione and pH. Folate-targeted HSA nanoparticles have shown higher cytotoxicity, cellular uptake, and apoptosis induction on folate receptor overexpressing MDA-MB-231 cells in comparison to non-targeted nanoparticles. Finally, it is considered that the developed dual-targeted nanoparticles would be potent in improving the stability and efficacy of intracellular delivery of Gem and its selective delivery to cancer cells.
- Norouzi, Parisa,Amini, Mohsen,Mottaghitalab, Fatemeh,Mirzazadeh Tekie, Farnaz Sadat,Dinarvand, Rassoul,Mirzaie, Zahra Hadavand,Atyabi, Fatemeh
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- Efficient and selective oxidation of thiols to disulfides by 1,4-diazabicyclo[2.2.2]octane-di-N-oxide-diperhydrate under neutral and heterogeneous conditions
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1,4-Diazabicyclo[2.2.2]octane-di-N-oxide-di-perhydrate selectively oxidizes thiols to disulfides in acetonitrile in good yields. The method is generally useful for a wide variety of thiols.
- Salehi, Peyman,Zolfigol, Mohammad Ali,Tolami, Leila Bazaz
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- Tribromoisocyanuric acid (TBCA) and oxone-MX systems as oxidizing agents: Oxidative coupling of thiols to their corresponding disulfides under mild and heterogeneous conditions
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Tribromoisocyanuric acid (TBCA) and Oxone-MX systems were used as effective oxidizing agents for the oxidation of thiols to their corresponding disulfides under mild conditions at room temperature with good to excellent yields.
- Zolfigol, Mohammad Ali,Niknam, Khodabakhsh,Bagherzadeh, Mojtaba,Ghorbani-Choghamarani, Arash,Koukabi, Nadiya,Hajjamia, Maryam,Kolvaria, Eskandar
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- Photocatalytic transformation of organic and water-soluble thiols into disulfides and hydrogen under aerobic conditions using Mn(CO)5Br
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The photolysis of Mn(CO)5Br with thiols under aerobic conditions at room temperature produces the corresponding disulfides in high yields, accompanied by the evolution of hydrogen as the only other product. This transformation is a greener route toward the synthesis of disulfides and exhibits 100% atom economy. The catalytic system possesses high chemoselectivity, as evidenced by high disulfide yields even in the presence of numerous functional groups. A mechanism has been proposed to involve free radical species and is based on fac-Mn(CO)3(RSH)2Br being an important catalytic intermediate. Mn(CO)5Br is also able to catalyze the conversion of naturally occurring water-soluble thiols such as cysteine and glutathione. Coupled with suitable enzymes that regenerate thiols from disulfides using proton sources, it is possible to envisage a combined catalytic cycle that is able to reduce protons to hydrogen efficiently.
- Tan, Kheng Yee Desmond,Teng, Guan Foo,Fan, Wai Yip
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- Silica chloride/NaNO2 as a novel heterogeneous system for production of thionitrites and disulfides under mild conditions
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Thiols can be readily converted to their corresponding thionitrites with a combination of silica chloride (I), wet SiO2 and sodium nitrite in dichloromethane at room temperature. Disulfides result from the homolytic cleavage of the sulfur-nitrogen bond of the unstable thionitrite and subsequent coupling of the resultant thiyl radicals.
- Zolfigol, Mohammad Ali,Shirini, Farhad,Choghamarani, Arash Ghorbani,Ghofrani, Efat
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- Oxidation of thiols with metal nitrates supported on TAFF
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Twelve thiols were readily oxidized to the corresponding disulfides by means of four metal nitrates supported on TAFF, a bentonitic clay, under mild conditions. However, in some cases, thioethers and other interesting by-products were detected. Some of the disulfides showed antimicotical activities against Aspergillus fumigatus, Aspergillus niger, Aspergillus candidus, Microsporum gypseum, Candida albicans, and Cryptococcus neoformans.
- Arroyo, Gabriel,Osnaya, Roberto,Cruz, Tonatiuh,Londono, Amparo,Alvarez, Cecilio,Delgado, Francisco,Santiago, Ricardo,Miranda, Rene
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- Oxidation of thiols to disulfides with molecular oxygen in subcritical water
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Molecular oxygen is used as an efficient oxidant for the oxidative coupling of thiols to disulfides in subcritical water in the absence of catalysts. The procedure utilizes water and does not require support materials and metal salts providing high yields (>90%). Springer-Verlag 2006.
- Ozen, Recep,Aydin, Fatma
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- Poly(N-bromobenzene-1,3-disulfonylamide), N,N,N′,N′- tetrabromobenzene-1,3-disulfonylamide and DABCO-bromine complex: As novel reagents for the oxidative coupling of thiols to disulfides
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An efficient method for the oxidative coupling of thiols to their corresponding disulfides by new reagents poly(N-bromobenzene-1,3- disulfonylamide) PBBS, N,N,N′,N′-tetrabromobenzene-1,3- disulfonylamide TBBDA and DABCO-bromine complex is described. The reaction was applicable to a variety of thiols with high chemoselectivity.
- Ghorbani-Vaghei, Ramin,Zolfigol, Mohammad Ali,Moshfeghifar, Nasrin,Koukabi, Nadiya,Chehardoli, Gholamabbas
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- SERS surfaces modified with a 4-(2-pyridylazo)resorcinol disulfide derivative: Detection of copper, lead, and cadmium
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We have developed a surface-enhanced Raman spectroscopic technique for the determination of Pb2+, Cd2+, and Cu2+ concentration using a 4-(2-pyridylazo)resorcinol (PAR) coating modified with a disulfide. The disulfide provided a strong anchor to a roughened silver substrate. Atomic specificity was demonstrated by the distinct spectral changes that occurred through the interaction of Pb2+, Cd2+, and Cu2+ ions with the indicator. The absorption of these metals by the coating was followed with SERS and could be fit to a Frumkin isotherm. Langmuirian behavior was not observed; this is most likely due to the electrostatic repulsions as the metal cations are absorbed. The detection limits at pH 6 for Pb2+, Cd2+, and Cu2+ were 522, 50.3, and 1.49 ppb, respectively. Flow experiments using an optical fiber probe indicated instantaneous response to changes in metal concentration.
- Gayle Crane,Wang, DaoXin,Sears, Malia,Heyns, Bernard,Carron, Keith
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- 1,3-Dibromo-5,5-dimethylhydantoin [DBDMH] as an efficient and selective agent for the oxidation of thiols to Disulfides in solution or under solvent-free conditions
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A useful method for oxidation of various thiols to their corresponding disulfides with 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) in very short reaction times and mild conditions under both solution and solvent-free conditions is described.
- Khazaei, Ardeshir,Zolfigol, Mohammad Ali,Rostami, Amin
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- Thiol-based michael-type addition. A systematic evaluation of its controlling factors
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This paper is about the factors controlling kinetics and product stability of this popular bioconjugation reaction. We demonstrate that a) thiol pKa, i.e. the amount of thiolates, is the only determinant of the reaction kinetics for the nucleophile; b) product degradation occurs primarily via hydrolysis (not thiol exchange), and is more prominent for the most rapidly reacting electrophiles. In terms of molecular design, acrylamides and low pKa thiols appear as the reaction partners that provide the best compromise for stability and reaction rate.
- Francini, Nora,Gennari, Arianna,Lallana, Enrique,Tirelli, Nicola,Wedgwood, Jennifer
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- Evidence for the Michaelis-Menton type mechanism in the electrocatalytic oxidation of mercaptopropionic acid by an amavadine model
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The amavadine complex and its model [VL2]2- (L = -ON[CH(CH3)COO-]2 (HIDPA3-) or -ON(CH2COO-)2 (HIDA3-), respectively) undergo, in aqueous medium and at a Pt electrode, a fully electrochemical and chemical reversible V(iv/v) oxidation and act as electron-transfer mediators in the electrocatalytic oxidation of some thiols (HSR) such as HS(CH2)(n)COOH (n = 1 or 2, i.e, mercaptoacetic or mercaptopropionic acid, respectively) and HSCH2CH(NH2)COOH (cysteine) to the corresponding disulfides (RS-SR) which were isolated upon bulk preparative electrolyses. As shown by digital simulation of cyclic voltammetry, this redox catalysis process occurs through an unprecedented mechanism involving Michaelis-Menten type kinetics with formation (k1 = 1.2 x 103 M-1 s-1) of an intermediate species (with half-life time of ca. 0.3 s) derived from the interaction of the oxidized vanadium complex (the active form of the mediator) with the substrate. A possible biological role for amavadine is suggested by these results.
- Guedes Da Silva, M. Fátima C.,Da Silva, J. Armando L.,Fraústo Da Silva, Jo?o J. R.,Pombeiro, Armando J. L.,Amatore, Christian,Verpeaux, Jean-No?l
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- Polydopamine as a Catalyst for Thiol Coupling
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In biological systems, disulfide bonds are formed efficiently under mild conditions without the release of harmful byproducts. Inspired by nature, we report a biomimetic polydopamine (PDA) catalyst for oxidative thiol coupling. This reaction was accelerated with only a small amount of PDA particles in neutral, weakly alkaline, and even weakly acidic aqueous media at room temperature under an air atmosphere. The catalytic particles were facilely separated and were reused without a decrease in activity. The entire process is totally biofriendly, including the synthesis of the PDA particles. This route is especially useful for the synthesis of pharmaceutical molecules. S-imulating nature: Inspired by disulfide bond formation mechanisms in nature, we demonstrate that polydopamine particles can be used as a promising biomimetic catalyst for the thiol coupling reaction in aqueous media under mild conditions. This approach involves no harmful chemicals and produces no waste products except for water.
- Du, Yong,Yang, Hao-Cheng,Xu, Xiao-Ling,Wu, Jian,Xu, Zhi-Kang
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- Thiol-dependent recovery of catalytic activity from oxidized protein tyrosine phosphatases
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Protein tyrosine phosphatases (PTPs) play an important role in the regulation of mammalian signal transduction. During some cell signaling processes, the generation of endogenous hydrogen peroxide inactivates selected PTPs via oxidation of the enzyme's catalytic cysteine thiolate group. Importantly, low-molecular weight and protein thiols in the cell have the potential to regenerate the catalytically active PTPs. Here we examined the recovery of catalytic activity from two oxidatively inactivated PTPs (PTP1B and SHP-2) by various low-molecular weight thiols and the enzyme thioredoxin. All monothiols examined regenerated the catalytic activity of oxidized PTP1B, with apparent rate constants that varied by a factor of approximately 8. In general, molecules bearing low-pKa thiol groups were particularly effective. The biological thiol glutathione repaired oxidized PTP1B with an apparent second-order rate constant of 0.023 ± 0.004 M-1 s -1, while the dithiol dithiothreitol (DTT) displayed an apparent second-order rate constant of 0.325 ± 0.007 M-1 s -1. The enzyme thioredoxin regenerated the catalytic activity of oxidized PTP1B at a substantially faster rate than DTT. Thioredoxin (2 μM) converted oxidized PTP1B to the active form with an observed rate constant of 1.4 × 10-3 s-1. The rates at which these agents regenerated oxidized PTP1B followed the order Trx > DTT > GSHand comparable values observed at 2 μM Trx, 4 mM DTT, and 60 mM GSH. Various disulfides that are byproducts of the reactivation process did not inactivate native PTP1B at concentrations of 1-20 mM. The common biochemical reducing agent tris(2-carboxyethyl)phosphine regenerates enzymatic activity from oxidized PTP1B somewhat faster than the thiol-based reagents, with a rate constant of 1.5 ± 0.5 M-1 s-1. We observed profound kinetic differences between the thiol-dependent regeneration of activity from oxidized PTP1B and SHP-2, highlighting the potential for structural differences in various oxidized PTPs to play a significant role in the rates at which low-molecular weight thiols and thiol-containing enzymes such as thioredoxin and glutaredoxin return catalytic activity to these enzymes during cell signaling events.
- Parsons, Zachary D.,Gates, Kent S.
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- Keactions of cysteine sulfenyl thiocyanate with thiols to give unsymmetrical disulfides
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Cysteine sulfenyl thiocyanate (CSSCN) reacts with thiols at pH 0 to cleanly yield disulfides. 2-Mercaptoethanol (2-MESH), 3-mercaptopropionic acid (3-MPASH), penicillamine (PENSH), and glutathione (GSH) react with CSSCN to give the corresponding mixed disulfides: 2-MESSC, 3-MPASSC, PENSSC, and GSSC. These compounds are stable at pH 0 and have been characterized by 1H and 13C NMR spectroscopy.
- Alguindigue Nimmo, Susan L.,Lemma, Kelemu,Ashby, Michael T.
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- Reactivity and O2 Formation by Mn(IV)- and Mn(V)-Hydroxo Species Stabilized within a Polyfluoroxometalate Framework
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Manganese(IV,V)-hydroxo and oxo complexes are often implicated in both catalytic oxygenation and water oxidation reactions. Much of the research in this area is designed to structurally and/or functionally mimic enzymes. On the other hand, the tendency of such mimics to decompose under strong oxidizing conditions makes the use of molecular inorganic oxide clusters an enticing alternative for practical applications. In this context it is important to understand the reactivity of conceivable reactive intermediates in such an oxide-based chemical environment. Herein, a polyfluoroxometalate (PFOM) monosubstituted with manganese, [NaH2(Mn-L)W17F6O55]q-, has allowed the isolation of a series of compounds, Mn(II, III, IV and V), within the PFOM framework. Magnetic susceptibility measurements show that all the compounds are high spin. XPS and XANES measurements confirmed the assigned oxidation states. EXAFS measurements indicate that Mn(II)PFOM and Mn(III)PFOM have terminal aqua ligands and Mn(V)PFOM has a terminal hydroxo ligand. The data are more ambiguous for Mn(IV)PFOM where both terminal aqua and hydroxo ligands can be rationalized, but the reactivity observed more likely supports a formulation of Mn(IV)PFOM as having a terminal hydroxo ligand. Reactivity studies in water showed unexpectedly that both Mn(IV)-OH-PFOM and Mn(V)-OH-PFOM are very poor oxygen-atom donors; however, both are highly reactive in electron transfer oxidations such as the oxidation of 3-mercaptopropionic acid to the corresponding disulfide. The Mn(IV)-OH-PFOM compound reacted in water to form O2, while Mn(V)-OH-PFOM was surprisingly indefinitely stable. It was observed that addition of alkali cations (K+, Rb+, and Cs+) led to the aggregation of Mn(IV)-OH-PFOM as analyzed by electron microscopy and DOSY NMR, while addition of Li+ and Na+ did not lead to aggregates. Aggregation leads to a lowering of the entropic barrier of the reaction without changing the free energy barrier. The observation that O2 formation is fastest in the presence of Cs+ and ~fourth order in Mn(IV)-OH-PFOM supports a notion of a tetramolecular Mn(IV)-hydroxo intermediate that is viable for O2 formation in an oxide-based chemical environment. A bimolecular reaction mechanism involving a Mn(IV)-hydroxo based intermediate appears to be slower for O2 formation.
- Schreiber, Roy E.,Cohen, Hagai,Leitus, Gregory,Wolf, Sharon G.,Zhou, Ang,Que, Lawrence,Neumann, Ronny
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- Thiocolchicine-podophyllotoxin conjugates: Dynamic libraries based on disulfide exchange reaction
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A dynamic combinatorial library of thiocolchicine-podophyllotoxin derivatives based on the disulfide bond exchange reaction is described. The influence of a biological target on the composition of the reaction mixture has been demonstrated. Use of high-resolution ESI mass spectrometry to evaluate the composition of the mixture shows promise for the design of new large libraries. The biological evaluation demonstrates that formation of a divalent compound affords a new chemical entity whose biological activity is not merely the sum of the single ligands activities, thus reflecting a different interaction with the biological target.
- Danieli, Bruno,Giardini, Alessandra,Lesma, Giordano,Passarella, Daniele,Peretto, Bruno,Sacchetti, Alessandro,Silvani, Alessandra,Pratesi, Graziella,Zunino, Franco
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- Macroporous p-type silicon Fabry-Perot layers. Fabrication, characterization, and applications in biosensing
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We present in this paper that porous silicon can be used as a large surface area matrix as well as the transducer of biomolecular interactions. We report the fabrication of heavily doped p-type porous silicon with pore diameters that can be tuned, depending on the etching condition, from approximately 5 to 1200 nm. The structure and porosity of the matrixes were characterized by scanning force microscopy (SFM) and scanning electron microscopy (SEM), Brunnauer-Emmett-Teller nitrogen adsorption isotherms, and reflectance interference spectroscopy. The thin porous silicon layers are transparent to the visible region of the reflectance spectra due to their high porosity (80-90%) and are smooth enough to produce Fabry-Perot fringe patterns upon white light illumination. Porous silicon matrixes were modified by ozone oxidation, functionalized in the presence of (2- pyridyldithiopropionamidobutyl)dimethylmethoxysilane, reduced to unmask the sulfhydryl functionalities, and coupled to biotin through a disulfide-bond- forming reaction. Such functionalized matrixes display considerable stability against oxidation and corrosion in aqueous media and were used to evaluate the utility of porous silicon in biosensing. The streptavidin-biotin interactions on the surface of porous silicon could be monitored by the changes in the effective optical thickness calculated from the observed shifts in the Fabry-Perot fringe pattern caused by the change in the refractive index of the medium upon protein-ligand binding. Porous silicon thus combines the properties of a mechanically and chemically stable high surface area matrix with the function of an optical transducer and as such may find utility in the fabrication of biosensor devices.
- Janshoff, Andreas,Dancil, Keiki-Pua S.,Steinem, Claudia,Greiner, Douglas P.,Lin, Victor S.-Y.,Gurtner, Christian,Motesharei, Kianoush,Sailor, Michael J.,Reza Ghadiri
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- The mechanism of oxidation of 3-mercaptopropionic acid
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The mechanism of the oxidation of 3-mercaptopropionic acid (3-MPA) by hydrogen peroxide was studied in the acidic pH range. The nucleophilic attack by sulphur on the peroxide bond controls the rate. Extrapolation of the pH dependency suggests that the rate of attack by the deprotonated dianion is highest. Traces of Fe(III), at levels below 10-7 mol dm-3, do not catalyze efficiently the process through one-electron mechanisms; at higher concentrations, or on the surface of iron(III) oxides, this type of catalysis becomes important. The electrochemical oxidation of 3-MPA was also studied, using differential pulse polarography and cyclic voltammetry techniques. The mechanism is of the EC2E type, the second electron transfer step corresponding to the oxidation of the disulphide RS-SR. The rate constant for the dimerization of the RS. radicals was 1.8 × 103 mol-1 dm3 s-1; the slowness of this step agrees with the mechanisms observed in the course of one-electron oxidations by metal ions.
- Forlano, Paula,Olabe, Jose A.,Magallanes, Jorge F.,Blesa, Miguel A.
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- Photochemical metal-free aerobic oxidation of thiols to disulfides
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Thiol oxidation to disulfides is an area of great importance in organic synthesis, both for synthetic and biological purposes. Herein, we report a mild, inexpensive and green photochemical approach for the synthesis of both symmetrical and non-symmetrical disulfides, using metal-free and environmentally friendly conditions. Utilizing phenylglyoxylic acid as the photoinitiator, common household bulbs as the light source and a simple inorganic salt as the additive, a versatile oxidation of thiols leading to products in excellent yields is described. This journal is
- Spiliopoulou, Nikoleta,Kokotos, Christoforos G.
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supporting information
p. 546 - 551
(2021/01/28)
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- Application of Bulky NHC-Rhodium Complexes in Efficient S-Si and S-S Bond Forming Reactions
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The efficient and straightforward syntheses of silylthioethers and disulfides are presented. The synthetic methodologies are based on new rhodium complexes containing bulky N-heterocyclic carbene (NHC) ligands that turned out to be efficient catalysts in thiol and thiol-silane coupling reactions. These green protocols, which use easily accessible reagents, allow obtaining compounds containing S-Si and S-S bonds in solvent-free conditions. Additionally, preliminary tests on coupling of mono- and octahydro-substituted spherosilicates with selected thiols have proved to be very promising and showed that these catalytic systems can be used for the synthesis of a novel class of functionalized silsesquioxane derivatives.
- Bo?t, Ma?gorzata,?ak, Patrycja
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supporting information
p. 17579 - 17585
(2021/11/18)
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- Self pH regulated iron(II) catalyst for radical free oxidation of benzyl alcohols
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Selective oxidation of various aromatic benzyl alcohols to benzaldehydes was found to be catalyzed with 90% conversion and 99% selectivity by an iron (II) catalyst herein designated as Fe-DDPA [DDPA = 3′-disulfanediyldipropionic acid]. The Fe-DDPA catalyst was prepared by a small loading of FeCl2 into a 2D sheet formed by the supramolecular assembling of DDPA. From both solid and liquid state nuclear magnetic resonance (NMR) spectroscopic study it was evident for the stabilization of the Fe(II) center through Fe-S interaction with the disulfide (S-S) unit of DDPA. DDPA was found to serve as an excellent support to maintain a pH that was required for a radical free oxidation of benzyl alcohol to aldehydes. The catalytic oxidation of benzyl alcohols was found to occur with excellent conversion and selectivity in acetonitrile (CH3CN) solvent in comparison to various other solvents. From various spectroscopic studies viz UV-vis, FT-IR and ESI-MS it was ascertained that the CH3CN interacted with Fe-DDPA to form a [(DDPA)2Fe(CH3CN)2]2+ species which then reacted with H2O2 to form an intermediate Fe-hydroxoperoxo, FeIII-OOH species. The Fe-OOH further got oxidized to the active FeIV=O species and was responsible for bringing the high selectivity in the oxidation reaction. The generation of highly unstable Fe-OOH species was further confirmed by electrochemical study, UV–vis, Raman and ESR spectroscopic analysis.
- Das, Biraj,Baruah, Manash J.,Sharma, Mukesh,Sarma, Bipul,Karunakar, Galla V.,Satyanarayana, Lanka,Roy, Subhasish,Bhattacharyya, Pradip K.,Borah, Kamala Kanta,Bania, Kusum K.
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- Cyclic telluride reagents with remarkable glutathione peroxidase-like activity for purification-free synthesis of highly pure organodisulfides
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Monoamino cyclic tellurides with a five- or six-membered ring structure and their derivatives were developed as a new class of catalyst for the oxidation of organothiols to organodisulfides in a glutathione peroxidase-like catalytic reaction. Quantitative conversion and high reaction rate were achieved by performing the reaction in an organic-aqueous segmented microflow system. Importantly, the process circumvented product purification, which is a major limitation of current organodisulfide synthetic methods.
- Arai, Kenta,Osaka, Yuui,Haneda, Masahiro,Sato, Yuumi
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p. 3647 - 3655
(2019/07/22)
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- METAL-CATALYZED OXIDATIVE COUPLING OF THIOLS
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Disclosed are methods for preparing disulfide compounds through oxidative coupling of thiol compounds. Thiols are oxidized to the corresponding disulfide compound in high yield in presence of a base and a metal salt. The method uses low catalyst loadings and provides organic disulfide compounds with little to no byproducts.
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Paragraph 0109; 0110
(2017/02/28)
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- Method for producing high-purity 3-thiohydracrylic acid
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The invention discloses a method for producing high-purity 3-thiohydracrylic acid. The method comprises the following steps that 1, an addition reaction is carried out, wherein acrylonitrile and sodium bisulfide are added to generate 3-mercapto propionic nitrile and sodium sulphide, sodium sulphide can react with acrylonitrile to generate disulfide generation malononitrile, and therefore an addition product is a mixture of 3-mercapto propionic nitrile and disulfide generation malononitrile; 2, a hydrolysis reaction is carried out, wherein in a hydrochloric acid system, the mixture of 3-mercapto propionic nitrile and disulfide generation malononitrile is hydrolyzed into a mixture of 3-thiohydracrylic acid and dithio malonic acid; 3, a reduction reaction is carried out, wherein in the hydrochloric acid system, dithio malonic acid is reduced into 3-thiohydracrylic acid through iron powder, and crude 3-thiohydracrylic acid is obtained after solvent extraction and solvent recovery; 4, a refining procedure is carried out, wherein crude 3-thiohydracrylic acid is rectified to obtain finished 3-thiohydracrylic acid. The defects in the prior art are overcome, the advantages of being low in cost and high in yield are achieved, all the reaction procedures are carried out under normal pressure, three wastes are reutilized, and almost no three wastes are discharged.
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Paragraph 0031; 0032; 0033; 0034; 0035
(2016/10/08)
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- Unusual multistep reaction of C70Cl10 with thiols producing C70[SR]5H
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We report a reaction of the chlorofullerene C70Cl10 with thiols producing C70[SR]5H with all organic addends attached around one central pentagon at the pole of the C70 cage. This reaction was shown to proceed via a complicated radical pathway, presumably involving addition, substitution, rearrangement, and/or elimination steps. The obtained C70[SR]5H products were shown to be very unstable and undergo quantitative decomposition to pristine C70, RSSR, and RSH at elevated temperatures (e.g., 50 °C). Quantum chemical calculations and NMR spectroscopy data showed that cleavage of organic addends from the fullerene cage could be induced by solvation effects in solution.
- Khakina, Ekaterina A.,Peregudov, Alexander S.,Yurkova, Anastasiya A.,Piven, Natalya P.,Shestakov, Alexander F.,Troshin, Pavel A.
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p. 1215 - 1219
(2016/03/01)
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- PROCESS FOR PREPARING ?-MERCAPTOCARBOXYLIC ACID
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There is provided a process for preparing β-mercaptocarboxylic acid represented by the following General Formula (3) comprising step of reacting hydrogen sulfide, alkali hydroxide represented by a formula: XOH (X represents Na or K), and unsaturated carboxylic acid represented by the following General Formula (1) under atmospheric pressure to obtain a reaction solution including a compound represented by the following General Formula (2) and step of neutralizing the reaction solution in an acid. An amount of the alkali hydroxide is equal to or greater than total moles of the unsaturated carboxylic acid and the hydrogen sulfide.
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Paragraph 0091-0095
(2014/09/30)
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- METHOD FOR PRODUCING BETA-MERCAPTOCARBOXYLIC ACID
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A process for preparing β-mercaptocarboxylic acid of the present invention is provided with Step a for reacting a compound represented by a formula: X12S (X1 represents hydrogen, Na or K) or a compound represented by a formula: X2SH (X2 represents Na or K), alkali hydroxide represented by a formula: X3OH (X3 represents Na or K), and unsaturated carboxylic acid represented by the following General Formula (1) to obtain a reaction solution including a compound represented by the following General Formula (2) and a compound represented by the following General Formula (3), Step b for neutralizing the reaction solution obtained in Step a with an acid to obtain a reaction solution including β-mercaptocarboxylic acid represented by the following General Formula (4) and a compound represented by the following General Formula (5), Step c for distillation-refining the reaction solution obtained in Step b to obtain the β-mercaptocarboxylic acid represented by General Formula (4), and Step d for returning a distillation residue including the compound represented by General Formula (5) in Step c to Step a.
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Paragraph 0094; 0095; 0096; 0097; 0098; 0099; 0100; 0107
(2014/10/15)
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- Mechanistic insights into the interface-directed transformation of thiols into disulfides and molecular hydrogen by visible-light irradiation of quantum dots
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Quantum dots (QDs) offer new and versatile ways to harvest light energy. However, there are few examples involving the utilization of QDs in organic synthesis. Visible-light irradiation of CdSe QDs was found to result in virtually quantitative coupling of a variety of thiols to give disulfides and H2 without the need for sacrificial reagents or external oxidants. The addition of small amounts of nickel(II) salts dramatically improved the efficiency and conversion through facilitating the formation of hydrogen atoms, thereby leading to faster regeneration of the ground-state QDs. Mechanistic studies reveal that the coupling reaction occurs on the QD surfaces rather than in solution and offer a blueprint for how these QDs may be used in other photocatalytic applications. Because no sacrificial agent or oxidant is necessary and the catalyst is reusable, this method may be useful for the formation of disulfide bonds in proteins as well as in other systems sensitive to the presence of oxidants. Copyright
- Li, Xu-Bing,Li, Zhi-Jun,Gao, Yu-Ji,Meng, Qing-Yuan,Yu, Shan,Weiss, Richard G.,Tung, Chen-Ho,Wu, Li-Zhu
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supporting information
p. 2085 - 2089
(2014/03/21)
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- Convenient synthesis and isolation of trifluoromethylthio-substituted building blocks
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Various aryl-, heteroaryl-, and alkyl mercaptanes (RSH, 1a-r) were treated with a slight excess of NaH suspended in DMF to make the appropriate sodium thiolates (RSNa), which then reacted with 1.3 equivalent of CF3I at room temperature for overnight to afford the appropriate trifluoromethyl sulfides (CF3SR, 2) in fair to good yields. The radical chain alkylation reaction was effective without the use of UV irradiation with all but three substrates (thiosalicylic acid, 1k; 2-mercaptobenzimidazole, 1q; and 3-mercaptopropionic acid, 1r). Steam-distillation was found as an effective and easy to upscale means for the isolation of these volatile and water immiscible sulfides. The CF3I reagent gas was conveniently weighed and delivered to the reaction mixture by the balloon technique or as a preliminary made stock solution in DMF or DMSO. The sulfides 2 obtained here were assayed by GC and characterized by 1H, 13C, 19F NMR and MS spectroscopy.
- Harsányi, Antal,Dorkó, éva,Csapó, ágnes,Bakó, Tibor,Peltz, Csaba,Rábai, József
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experimental part
p. 1241 - 1246
(2011/11/12)
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- Oxidation of thiols using K2S2O8 in ionic liquid
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A green, straightforward, and novel method for oxidation of thiols to the corresponding disulfides is reported using K2S2O8 in the ionic liquid 1-butyl-3-methylimidazolium bromide [(bmim)Br] at 65-70C. The corresponding disulfides were obtained in excellent yield and short reaction time.
- Hajipour, Abdol R.,Mostafavi, Majid,Ruoho, Arnold E.
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experimental part
p. 1920 - 1923
(2010/02/28)
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- Carboxy pyridinium bromide perbromide reagents, part I: Selective oxidation of thiols and sulfides
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Efficient and convenient oxidation of aliphatic and aromatic thiols to disulfides and of sulfides to sulfoxides with pyridinium hydrobromide perbromide (PHBP), nicotinic acid hydrobromide perbromide (NAHBP), and 2,6-dicarboxy pyridinium hydrobromide perbromide (DCPHBP) in a solvent or under solvent free conditions and at ambient temperature is introduced. Copyright Taylor & Francis Group, LLC.
- Lakouraj, Moslem M.,Ghodrati, Keivan
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experimental part
p. 1432 - 1439
(2009/05/07)
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- Substituted isothiazolones
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This invention is directed to a compound of Formula (I): and pharmaceutically acceptable forms thereof useful as inhibitors of cPLA2 and a method for preventing, treating or ameliorating a cPLA2 mediated inflammatory related disease, disorder or condition using a compound of Formula (I) and, more particularly, for preventing, treating or ameliorating a cPLA2 mediated inflammatory related disease, disorder or condition which results from the cellular secretion of TXB2 or LTB4.
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Page/Page column 14
(2010/11/25)
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- Substantially cell membrane impermeable compound and use thereof
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The present invention relates to a compound according to Formula (I): A-(L-Y)p, wherein A comprises at least one substantially cell-membrane impermeable pendant group; L comprises any suitable linker and/or spacer group; Y comprises at least one arsenoxide or arsenoxide equivalent; p is an integer from 1 to 10; and the sum total of carbon atoms in A and L together, is greater than 6.
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Page/Page column 43-44
(2008/06/13)
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- Design and synthesis of substrate and intermediate analogue inhibitors of S-ribosylhomocysteinase
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S-Ribosylhomocysteinase (LuxS) catalyzes the cleavage of the thioether linkage in S-ribosylhomocysteine (SRH) to produce homocysteine and 4,5-dihydroxy-2,3-pentanedione, the precursor of autoinducer 2. Inhibitors of LuxS should interfere with bacterial interspecies communication and potentially provide a novel class of antibacterial agents. LuxS utilizes a divalent metal ion as a Lewis acid during catalysis. In this work, a series of structural analogues of the substrate SRH and a 2-ketone intermediate were designed and synthesized. Kinetic studies indicate that the compounds act as reversible, competitive inhibitors against LuxS, with the most potent inhibitors having K1 values in the submicromolar range. These represent the most potent LuxS inhibitors that have been reported to date. Cocrystal structures of LuxS bound with two of the inhibitors largely confirmed the design principles, i.e., the importance of both the homocysteine and ribose moieties in high-affinity binding to the LuxS active site.
- Shen, Gang,Rajan, Rakhi,Zhu, Jinge,Bell, Charles E.,Pei, Dehua
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p. 3003 - 3011
(2007/10/03)
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- A new application of N,N′-dibromo-N,N′-1,2-ethanediylbis(p- toluenesulfonamide) as selective and efficient reagent for the oxidation of various thiols to disulfides
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An efficient method for oxidation of thiol to their corresponding disulfides in high yields with N,N′-Dibromo-N,N′-1,2-ethanediyl bis (p-toluensulphonamide) in dichloromethane at room temperature is described. Copyright Taylor & Francis Inc.
- Khazaei, Ardeshir,Rostami, Amin
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p. 555 - 557
(2007/10/03)
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- 3-Carboxypyridinium trichloroacetatochromate (CPTCAC): As a mild and effective new reagent for the thiols to disulfides
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A new chromium(VI) reagent, 3-carboxypyridinium trichloroacetatochromate (CPTCAC) was prepared by reacting 3-carboxypyridine (nicotinic acid) and trichloroacetic acid with CrO3 in water. This oxidising agent oxidised the thiols to disulfides selectivity and in very high yields.
- Aydin, Fatma,Ozen, Recep
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p. 224 - 226
(2007/10/03)
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- N-Bromophthalimide [NBPI] as a powerful oxidizing agent for the facile and chemoselective oxidation of thiols to symmetrical disulfides
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A new application of N-bromophthalimide for the facile oxidation of thiols to their corresponding symmetrical disulfides is described. A wide variety of thiols (aromatic, aliphatic and heterocyclic) were selectively oxidised to their corresponding disulfides with [NBPI] in a mixture of acetone and water under microwave irradiation in a microwave oven at a power output of 650W.
- Khazaei, Ardeshir,Manesh, Abbas Amini,Rostami, Amin
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p. 391 - 393
(2007/10/03)
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- Oxidation of thiols with 1-butyl-4-aza-1-azoniabicyclo[2.2.2]octane dichromate (BABOD) under non-aqueous conditions
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The preparation of 1-butyl-4-aza-1-azoniabicyclo[2.2.2]octane dichromate and the use of this reagent for selective oxidation of aromatic and aliphatic thiols to their corresponding disulfides under non-aqueous conditions is reported.
- Hajipoura,Bagheri, Hamid,Ruoho, Arnold E.
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p. 286 - 287
(2007/10/03)
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- Oxidation of thiols to the corresponding symmetric disulfides with benzyltriphenylphosphonium peroxodisulfate (BTPPD) under nonaqueous conditions
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This article describes the preparation of benzyltriphenylphosphonium peroxodisulfate (BTPPD), an efficient and mild reagent for oxidation of a variety of aromatic and aliphatic thiols to the corresponding disulfides in refluxing acetonitrile. The experimental procedure is simple and the products are easily isolated in excellent yields.
- Hajipour, Abdol R.,Ruoho, Arnold E.
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p. 1277 - 1281
(2007/10/03)
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- Oxidation of thiols to the corresponding disulfides with tetramethylammonium chlorochromate under non-aqueous conditions
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This paper describes the preparation of tetramethylammonium chlorochromate (TMACC) as an efficient and mild reagent for oxidation in refluxing acetonitrile of a variety of aromatic and aliphatic thiols, giving the corresponding disulfides; the experimental procedure is simple, and the products are easily isolated in excellent yields.
- Hajipour, Abdol R.,Ruoho, Arnold E.
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p. 547 - 549
(2007/10/03)
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- Design and synthesis of a bifunctional label for selection of β-lactamase displayed on filamentous bacteriophage by catalytic activity
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A bifunctional activity label 1c has been constructed for the selection of active β-lactamases displayed on filamentous bacteriophage. It features an original 6-sulfonylamido-penam sulfone moiety, as β-lactamase suicide-inhibitor, and a biotinyl residue, for separation by affinity chromatography, connected through a linker including a cleavable disulfide bond. The inhibitor 28 resulted from coupling of methoxymethyl 6-aminopenicillinate 8 with N-protected (aminoethoxy)ethoxyethanesulfonyl chloride 23, followed by oxidation into the corresponding sulfone 25, and usual deprotections. The biotinyl ester 32 reacted with 3-(2-aminoethyldithio)propanoic acid 31 as linker, to give 33 which was further activated as pentafluorophenol ester 34b. Final coupling of the building blocks 28 and 34b gave the target label 1c.
- Marchand-Brynaert, Jacqueline,Bouchet, Michele,Touillaux, Roland,Beauve, Cecile,Fastrez, Jacques
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p. 5591 - 5606
(2007/10/03)
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- Kinetics and mechanism of the oxidation of some thioacids by benzyltrimethylammonium dichloroiodate
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The oxidation of thioglycolic, thiolactic, and thiomalic acids by benzyltrimethylamrnonium dichloroiodate (BTMAIC) to the corresponding disulfide dimer, is first-order with respect to each the thioacid and BTMAIC. The rates of oxidation were determined at different temperatures and the activation parameters were evaluated. The reaction failed to induce polymerization of acrylonitrile. The reaction rate increases with the increase in the concentration of zinc chloride. Addition of benzyltrimethylammonium chloride enhances the reaction rate. Suitable mechanism has been proposed.
- Suri, Deepa,Kothari, Seema,Banerji, Kalyan K.
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p. 681 - 685
(2007/10/03)
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- Catalysis by Cu2+ of nitric oxide release from S-nitrosothiols (RSNO)
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The decomposition of a range of S-nitrosothiols (thionitrites) RSNO, based on cysteine derivatives, yields in water at pH 7.4 nitrite ion quantitatively.If oxygen is rigorously excluded then no nitrite ion is formed and nitric oxide can be detected using an NO-probe.The reaction is catalysed by trace quantities of Cu2+ (there is often enough present in distilled water samples) and also to a lesser extent by Fe2+, but not by Zn2+, Cu2+, Mg2+, Ni2+, Co2+, Mn2+, Cr3+ or Fe3+.The rate equation (measuring the disappearance of the absorption at ca. 350 nm due to RSNO) was established as v = k*2+> + k' over a range of 2+> typically 5-50 μmol dm-3.The constant term k' represents the component of the rate due to residual Cu2+ in the solvent and buffer components, together with the spontaneous thermal reaction.Decomposition can be virtually halted by the addition of EDTA.Reactions carried out in the presence of N-methylaniline gave a quantitative yield of N-methyl-N-nitrosoaniline, but a negligible yield when oxygen was rigorously excluded.Values of the second-order rate constant k were obtained for a range of S-nitrosothiols.Reactivity is highest for the S-nitrosothiols derived from cysteamine and penicillamine, when Cu2+ can be complexed both with the nitrogen atom of the nitroso group and the nitrogen atom of the amino group, via a six-membered ring intermediate.If there is no amino (or other electron donating group) present, reaction is very slow (as for RSNO derived from a tert-butyl sulfide).N-Acetylation of the amino group reduces the reactivity drastically as does the introduction of another CH2 group in the chain.There is evidence of a significant gem-dimethyl effect.Kinetic results using the S-nitrosothiols derived from mercaptoacetic, thiolactic and thiomalic acids suggests that coordination can also occur via one of the oxygen atoms of the carboxylate group.EPR experiments which examined the Cu2+ signal showed no spectral change during the reaction suggesting that the mechanism does not involve oxidation and reduction with Cu2+ Cu+ interconversion.
- Askew, Stuart C.,Barnett, D. Jonathan,McAninly, John,Williams, D. Lyn H.
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p. 741 - 746
(2007/10/02)
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- Mechanistic Studies of Fluorodecarboxylation with Xenon Difluoride
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The reaction of xenon difluoride with primary carboxylic acids involves a free-radical mechanism.Trifluoroacetic acid (1) decarboxylates in benzene to give (trifluoromethyl)benzene (2). 6-Hexenoic acid (3) produces a free radical in a radical clock reaction in which the kabs (25 deg C) for XeF2 was determined as 1.1 * 106 M-1 s-1.The primary radical from hexanoic acid was spin-trapped to give ESR signals diagnostic for the alkyl radical.Secondary acids were shown to proceed through a trivalent intermediate, but its exact nature was not proven.The acid 6 gave a rearranged product (7) characteristic of carbocations, whereas the diacid 8 gave difluoro compounds without stereoselectivity.The tertiary bicyclic acids 13 and 15 gave products only from solvent hydrogen abstraction strongly indicative of free radicals.
- Patrick, Timothy B.,Khazaeli, Sadegh,Nadji, Sourena,Hering-Smith, Katy,Reif, Dirk
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p. 705 - 708
(2007/10/02)
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- Kinetics and Equilibria of Thiol/Disulfide Interchange Reactions of Selected Biological Thiols and Related Molecules with Oxidized Glutathione
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Rate constants for reaction of coenzyme A and cysteine with oxidized glutathione (GSSG) and equilibrium constants for the reaction of coenzyme A, cysteine, homocysteine, cysteamine, and related thiols with GSSG by thiol/disulfide interchange were determined over a range of pD values by NMR spectroscopy.The rate constants for reaction of the thiolate anion forms of coenzyme A and cysteine with GSSG suggest that reduction of GSSG by coenzyme A and cysteine is a mechanistically uncomplicated SN2 reaction.Equilibrium constants for the thiol/disulfide interchange reactions show a strong dependence on the Bronsted basicity of the thiolate anion.In a similar way, ΔE0', the difference between the half-cell potentials for the RSSR/RSH and GSSG/GSH redox couples, is linearly dependent on the difference between the pKA values of RSH and glutathione: ΔE0' = 64ΔpKA - 7.7 where ΔE0' is in units of mV.The reducing strength at a given pH is also determined by the fraction of the thiol present in the reactive thiolate form.At pD 7, the half-cell potentials for coenzyme A, cysteine, homocysteine, and cysteamine are close to that of glutathione, the major intracellular thiol redox system, which suggests that small changes in the intracellular redox potential can cause significant changes in the intracellular distribution of these biological thiols between their reduced and oxidized forms.
- Keire, David A.,Strauss, Erin,Guo, Wei,Noszal, Bela,Rabenstein, Dallas L.
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p. 123 - 127
(2007/10/02)
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