Reactive Sulfur Species: Kinetics and Mechanism of the Oxidation of Aryl Sulfinates with Hypochlorous Acid

Ueki, Hironobu; Chapman, Garry; Ashby, Michael T.

doi:10.1021/jp906651n

Cited by 6 publications

(5 citation statements)

References 32 publications

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“…NMR titration results, also affording effective K d values, corroborated the crystal data by characteristic 19 F chemical shifts and through hydrogen/deuterium primary isotope shifts. The magnitude of the isotope shifts and quantitation of 1 H- 19 F NOEs afforded solution structure measurements. These results suggest that a pentacoordinate phosphorane is not appropriate to describe the transition structure.…”

Section: Transfer At Phosphorussupporting

confidence: 68%

“…À derivatives by HOCl/OCl À is normally expected to proceed through nucleophilic attack of ArSO 2 À on HOCl, with concomitant transfer of Cl + , however an alternative mechanism with OCl À nucleophilic attack on ArSO 2 À , to form a sulfurane intermediate (ArSO 2 Cl 2À ) has recently been proposed and tested. 19 These reactions were followed by UV-vis spectroscopy, and products also were confirmed by 1 H NMR spectroscopy and HPLC analysis, with ArSO 2 Cl, not a sulfurane, identified as an intermediate. The rate of hydrolysis of ArSO 2 Cl was studied between pH 0 and 13.7 and afforded pseudo-first order kinetics with ArSO 3 À identified as the product.…”

Section: Oxidation Of Arsomentioning

confidence: 88%

“…Using MgF 3 À as a metaphosphate anion (PO 3 À ) analogue, high-resolution X-ray crystallography and 19 F NMR have been used to illuminate details of the transition-state structure of phosphorous transfer in b-phosphoglucomutase Scheme 8 NAD + -dependent acyl transfer from lysine is judged, through measurement of 13 C and 3 H competitive KIEs, to proceed through a dissociative, oxacarbenium transition state.…”

Section: Transfer At Phosphorusmentioning

confidence: 99%

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Reaction mechanisms: polar reactions

Croft¹,

Davies²

2011

Annu. Rep. Prog. Chem., Sect. B: Org. Chem.

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This review presents highlights from papers published in 2010 reporting the mechanistic studies of polar reactions across a diverse range of fields, and is primarily focussed on experimental investigations. A number of examples related to biological systems are included, where the reaction mechanisms are often both complicated and enhanced by supramolecular factors. The breadth of modern physical organic chemistry means that the subheadings used throughout the review should be used as guidelines, as for many studies it is possible to categorise them in a number of different ways. Hydrogen transferThe transfer of hydrogen, whether as a proton or as hydride, is an important step in many different processes. As such, this section covers a range of reactions where hydrogen plays a central role.Natural processes are a rich source of hydrogen transfer reactions, and, in particular, the ability of protons and hydride anions to be transferred with extremely large kinetic isotope effects (KIEs) through tunnelling remains intriguing. The effect of distance between the donor and acceptor for hydride transfer on force constants in enzymecatalysed reactions has been examined for the enzyme morphinone reductase (Scheme 1). 1 Scheme 1 Hydride transfer from NADH to FMN in morphinone reductase.

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Section: Transfer At Phosphorussupporting

confidence: 68%

Section: Oxidation Of Arsomentioning

confidence: 88%

Section: Transfer At Phosphorusmentioning

confidence: 99%

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Reaction mechanisms: polar reactions

Croft¹,

Davies²

2011

Annu. Rep. Prog. Chem., Sect. B: Org. Chem.

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“…Step R5 is a competitive process with step R4 that leads to the formation of S 2 O 3 I − instead of hypoiodous acid and S 2 O 3 OH − . This process is a formal electrophilic I + transfer frequently occurring in different oxidation reactions of hypohalogenous acids. , It may seem surprising that hypoiodous acid can react with thiosulfate via an oxygen transfer (step R4) and a I + transfer (step R5) pathway simultaneously as well, but this result is not a unique feature of the kinetic behavior of hypohalogenous acid. Fogelman et al have already reported that hypochlorous acid reacts with sulfite via parallel oxygen transfer and Cl + transfer to produce sulfate and chloride eventually.…”

Section: Discussionmentioning

confidence: 99%

Complex Kinetics of a Landolt-Type Reaction: The Later Phase of the Thiosulfate−Iodate Reaction

Varga

Nagypál²,

Horváth³

2010

J. Phys. Chem. A

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The thiosulfate-iodate reaction has been studied spectrophotometrically in slightly acidic medium at 25.0 +/- 0.1 degrees C in acetate/acetic acid buffer by monitoring the absorbance at 468 nm at the isosbestic point of iodine-triiodide ion system. The formation of iodine after the Landolt time follows a rather complex kinetic behavior depending on the pH and on the concentration of the reactants as well. It is shown that the key intermediate of the reaction is I(2)O(2), its equilibrium formation from the well-known Dushman reaction along with their further reactions followed by subsequent reactions of HOI, HIO(2), S(2)O(3)OH(-), and S(2)O(3)I(-) adequately accounts for all the experimentally measured characteristics of the kinetic curves. A 19-step kinetic model is proposed and discussed with 13 fitted and 7 fixed parameters in detail.

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“…It is therefore rather amazing—and in many ways very fortunate—that the field of inorganic RSS over the years has developed its own dynamic, fuelled by three parallel developments: (a) the stream of ten prominent publications on inorganic RSS by Michael Ashby and his colleagues between 2004 and 2010, all with a title commencing with “Reactive Sulfur Species” and focussed on inorganic RSS [46,72,73,74,75,76,77,78,79,80,81], (b) The eruption of H 2 S research, accompanied by the suspicion that H 2 S is probably not really the signalling molecule one had previously thought, but that there is a case of mistaken identity, involving an entire series of inorganic polysulfides (H 2 S x ), which clearly belong to the realm of inorganic RSS, (c) the issue of the lost electron, i.e., the rather curious situation that many interactions involving thiols and radicals, for instance in the field of S-nitrosothiols, do not add up when it comes to electrons, hence questioning if RSS are really predominantly electrophilic compounds, such as sulfenic acids, or rather radical species. We will now consider the inorganic side of sulfide species in more detail.…”

Section: What Are Rss?mentioning

confidence: 99%

The Reactive Sulfur Species Concept: 15 Years On

et al. 2017

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Fifteen years ago, in 2001, the concept of “Reactive Sulfur Species” or RSS was advocated as a working hypothesis. Since then various organic as well as inorganic RSS have attracted considerable interest and stimulated many new and often unexpected avenues in research and product development. During this time, it has become apparent that molecules with sulfur-containing functional groups are not just the passive “victims” of oxidative stress or simple conveyors of signals in cells, but can also be stressors in their own right, with pivotal roles in cellular function and homeostasis. Many “exotic” sulfur-based compounds, often of natural origin, have entered the fray in the context of nutrition, ageing, chemoprevention and therapy. In parallel, the field of inorganic RSS has come to the forefront of research, with short-lived yet metabolically important intermediates, such as various sulfur-nitrogen species and polysulfides (Sx2−), playing important roles. Between 2003 and 2005 several breath-taking discoveries emerged characterising unusual sulfur redox states in biology, and since then the truly unique role of sulfur-dependent redox systems has become apparent. Following these discoveries, over the last decade a “hunt” and, more recently, mining for such modifications has begun—and still continues—often in conjunction with new, innovative and complex labelling and analytical methods to capture the (entire) sulfur “redoxome”. A key distinction for RSS is that, unlike oxygen or nitrogen, sulfur not only forms a plethora of specific reactive species, but sulfur also targets itself, as sulfur containing molecules, i.e., peptides, proteins and enzymes, preferentially react with RSS. Not surprisingly, today this sulfur-centred redox signalling and control inside the living cell is a burning issue, which has moved on from the predominantly thiol/disulfide biochemistry of the past to a complex labyrinth of interacting signalling and control pathways which involve various sulfur oxidation states, sulfur species and reactions. RSS are omnipresent and, in some instances, are even considered as the true bearers of redox control, perhaps being more important than the Reactive Oxygen Species (ROS) or Reactive Nitrogen Species (RNS) which for decades have dominated the redox field. In other(s) words, in 2017, sulfur redox is “on the rise”, and the idea of RSS resonates throughout the Life Sciences. Still, the RSS story isn’t over yet. Many RSS are at the heart of “mistaken identities” which urgently require clarification and may even provide the foundations for further scientific revolutions in the years to come. In light of these developments, it is therefore the perfect time to revisit the original hypotheses, to select highlights in the field and to question and eventually update our concept of “Reactive Sulfur Species”.

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Reactive Sulfur Species: Kinetics and Mechanism of the Oxidation of Aryl Sulfinates with Hypochlorous Acid

Cited by 6 publications

References 32 publications

Reaction mechanisms: polar reactions

Reaction mechanisms: polar reactions

Complex Kinetics of a Landolt-Type Reaction: The Later Phase of the Thiosulfate−Iodate Reaction

The Reactive Sulfur Species Concept: 15 Years On

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