- Effects of sulfane sulfur content in benzyl polysulfides on thiol-triggered H2S release and cell proliferation
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Investigations into hydrogen sulfide (H2S) signaling pathways have demonstrated both the generation and importance of persulfides, which are reactive sulfur species that contain both reduced and oxidized sulfur. These observations have led researchers to suggest that oxidized sulfur species, including sulfane sulfur (S0), are responsible for many of the physiological phenomena initially attributed to H2S. A common method of introducing S0 to biological systems is the administration of organic polysulfides, such as diallyl trisulfide (DATS). However, prior reports have demonstrated that commercially-available DATS often contains a mixture of polysulfides, and furthermore a lack of structure-activity relationships for organic polysulfides has limited our overall understanding of different polysulfides and their function in biological systems. Advancing our interests in the chemical biology of reactive sulfur species including H2S and S0, we report here our investigations into the rates and quantities of H2S release from a series of synthetic, pure benzyl polysulfides, ranging from monosulfide to tetrasulfide. We demonstrate that H2S is only released from the trisulfide and tetrasulfide, and that this release requires thiol-mediated reduction in the presence of cysteine or reduced glutathione. Additionally, we demonstrate the different effects of trisulfides and tetrasulfides on cell proliferation in murine epithelial bEnd.3 cells.
- Bolton, Sarah G.,Cerda, Matthew M.,Gilbert, Annie K.,Pluth, Michael D.
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- Silylating Disulfides and Thiols with Hydrosilicones Catalyzed by B(C6F5)3
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Hydrosilanes and silicones, catalyzed with B(C6F5)3, may be used to silylate thiols or cleave disulfides giving silyl thio ethers. Alcohols were found to react faster than thiols or disulfides, while alkoxysilanes (the Piers-Rubinsztajn reaction) were slower such that the overall order of reactivity was found to be HO>HS>SS>SiOEt. The resulting silane and silicone-protected thio ethers produced from the sulfur-based functional groups could be cleaved to thiols using alcohols or mild acid with rates that depend on the steric bulk of the siloxane.
- Brook, Michael A.,Liao, Mengchen,Zheng, Sijia
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supporting information
p. 2694 - 2700
(2021/06/25)
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- COMPOSITIONS AND METHODS FOR TREATING OR PREVENTING HYPOXIC OR ISCHEMIC INJURY
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A method for treating or preventing injury of a biological material exposed to hypoxic or ischemic conditions comprising contacting the biological material with an effective amount of a compound is disclosed. The compound has the following structure (I):
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Page/Page column 40
(2010/04/30)
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- Direct preparation of anhydrous sodium oligosulfides from metal sodium and elemental sulfur in aprotic organic media directed toward synthesis of silane coupling agent
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Anhydrous sodium oligosulfide was prepared by the heterogeneous reaction of metal sodium and elemental sulfur in aprotic solvents. The oligosulfide consisted of a mixture of several Na2Sn (n = 2 - 8). Organic oligosulfides (R2Sn, n ≥ 2) including moisture-sensitive one were synthesized by the reaction with organic halides in high yeilds under mild conditions.
- Yamada, Nobuo,Furukawa, Mutsuhisa,Nishi, Masayuki,Takata, Toshikazu
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p. 454 - 455
(2007/10/03)
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- Insertion of a two sulfur unit into the S-S bond - Tailor-made polysulfides
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Triphenylthiosulfenyl chloride (1) reacts with disulfides RSSR, yielding tetrasulfides as the main products. The results of the insertion for different R groups are reported. A two-step mechanism involving the formation of unsymmetrical trisulfide intermediates containing the trityl group is proposed. (C) 2000 Elsevier Science Ltd.
- Rys,Harpp
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p. 7169 - 7172
(2007/10/03)
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- Nucleophilic substitution of alkyl halides by electrogenerated polysulfide ions in N,N-dimethylacetamide
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The reactions between a series of alkyl halides RX: X = I, R = CH3 (1), C3H7 (2); X = Br, R = C4H9 (3), 2-C4H9 (4), 3-C5H11 (5), PhCH2 (6); X = Cl, R = PhCH2 (7), C6H13 (8), and electrogenerated S1/3- ions (S62- ?S3.-) have been investigated by spectroelectrochemistry in N,N-dimethylacetamide at 20°C. RX substrates react in two steps: (i) nucleophilic substitution of S1/3- ions (SN2 process) yielding RSx- ions (x = 5.2, R = alkyl; x = 4.8, R = PhCH2); (ii) subsequent substitutions of RSx- ions lead to RSzR polysulfanes (z ≈ 3.5), probably through partial disproportionation of the anionic species. On a preparative scale, mixtures of CH3SzCH3 (z = 2-6, z = 3.9) or PhCH2Sz CH2Ph (z = 2-5, z = 3.7) were obtained from chemical reactions between 1, 6 and S62- ions, or electrochemical syntheses. Kinetic studies at 20°C of the reactions between S3.- ions and substrates 4, 5, 7 and 8 imply that the dianions S62- are the nucleophilic agents in the first step rather than S3.- radical anions.
- Ahrika, Abdelkader,Robert, Julie,Anouti, Meriem,Paris, Jacky
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p. 513 - 520
(2007/10/03)
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- Use of a sacriflcial-sulfur electrode in electroorganic chemistry. V. Formation of the sequence CSSSC from S and thiols or thiolates
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At a working potential of about +2.0 V (vs SCE) the carbon-sulfur electrode is a source of the electrogenerated cation S2+. In organic media, this electrophile reacts with thiols (or thiolates) to give a mixture of polysulfides of which the trisulfide is the main product. The reaction between electrogenerated Sy2- and alkyl halides is less selective. Elsevier,.
- Do, Quang Tho,Elothmani, Driss,Simonet, Jacques,Guillanton, Georges Le
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p. 273 - 281
(2007/10/03)
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- Reactions of Triphenylphosphine with Di-, Tri-, or Tetrasulphides, or with Sulphur, in Hydroxylic Solvents.
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In contrast to the behaviour of disulphides RS2R, the mono-desulphurisation of tri- or tetra-sulphides RSnR (R = benzyl, p-tolyl; n= 3, 4) by triphenylphosphine in hydroxylic solvents (methanol-benzene or water- 2-propanol-benzene) mainly affords Ph3PS with only small (n = 3) or very small (n = 4) amounts of Ph3PO.Ph3PO was virtually absent in the reaction products of Ph3P with 2Sn (n = 2, 3) or with elemental sulphur in alcoholic or aqueous media.Reaction rates for the formation of Ph3PS or Ph3PO decrease in the order: RS4R > RS3R >> RS2R (R = benzyl or p-tolyl) and hydroxylic >> aprotic solvents; the dependence on R is: (EtO)2P(S) >> p-tolyl > benzyl.Addition of a thiol impedes the formation of Ph3PO; low pH's have an opposite effect.The results are rationalised in terms of basicity of anions RSp- (p = 1 to n-1), relative softness of terminal or central S in RSnR and Broensted acidity of the solvent.An alternative is proposed to the Bartlett's mechanism for the reaction of S8 with Ph3P, in which the intermediate zwitterion Ph3P+S4- collapses by fast intramolecular nucleophilic displacement, affording Ph3PS and highly reactive S7.
- Demarcq, Michel C.
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p. 3052 - 3080
(2007/10/02)
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- Sulfur-Sulfur Bond Cleavage Processes. Selective Desulfurization of Trisulfides
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The selectivity of sulfur removal in the desulfurization of trisulfides by tertiary phosphorus compounds has been investigated in detail.A mechanistic rationalization is proposed to account for central/terminal sulfur extrusion variation as a function of substrate structure and solvent polarity.
- Harpp, David N.,Smith, Roger A.
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p. 6045 - 6053
(2007/10/02)
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