- Acid-Catalyzed Hydrolysis of Methoxymethyl Phenyl Sulfoxide without Concomitant Racemization
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Methoxymethyl phenyl sulfoxide 1 undergoes acid-catalyzed hydrolysis to give S-phenyl benzenethiosulfinate 5, which is formed rapidly from a primary product, benzenesulfenic acid 3.Formation of 5 follows pseudo-first-order kinetics.Rate constants obtained
- Okuyama, Tadashi,Toyoda, Masayoshi,Fueno, Takayuki
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Read Online
- Natural product inspired allicin analogs as novel anti-cancer agents
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A series of novel analogs of Allicin (S-allyl prop-2-ene-1-sulfinothioate) present in garlic has been synthesized in high yield. Synthesized 23 compounds were evaluated against different breast cancer cells (MDA-MB-468 and MCF-7) and non-cancer cells (WI38). Four compounds (3f, 3h, 3m and 3u) showed significant cytotoxicity against cancer cells whereas nontoxic to the normal cells. Based on the LD50 values and selectivity index (SI), compound 3h (S-p-methoxybenzyl (p-methoxyphenyl)methanesulfinothioate) was considered as most promising anticancer agent amongst the above three compounds. Further bio-chemical studies confirmed that compound 3h promotes ROS generation, changes in mitochondrial permeability transition and induced caspase mediated DNA damage and apoptosis.
- Bhaumik, Ishani,Pal, Kunal,Debnath, Utsab,Karmakar, Parimal,Jana, Kuladip,Misra, Anup Kumar
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p. 259 - 272
(2019/02/07)
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- One-pot synthesis of α-phenylsulfinyl ketones by reaction of phenyl benzenethiosulfinate with enolate anions, and synthesis of sulfoxides and sulfides by its reaction with Grignard reagents
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Phenyl benzenethiosulfinate reacts with enolate anions derived from ketones to give α-phenylsulfinyl ketones directly, together with minor amounts of α-phenylsulfanyl ketones. These are easily separated by forming the water-soluble sodium salts of the sulfinyl compounds. Grignard reagents also react with phenyl benzenethiosulfinate, to give mixtures of sulfoxides and sulfides.
- Fakhry, Jerome,Grayson, David H.
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p. 556 - 563
(2017/12/28)
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- Oxidation of disulfides to thiolsulfinates with hydrogen peroxide and a cyclic seleninate ester catalyst peroxide and a cyclic seleninate ester catalyst
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Cyclic seleninate esters function as mimetics of the antioxidant selenoenzyme glutathione peroxidase. They catalyze the reduction of harmful peroxides with thiols, which are converted to disulfides in the process. The possibility that the seleninate esters could also catalyze the further oxidation of disulfides to thiolsulfinates and other overoxidation products under these conditions was investigated. This has ramifications in potential medicinal applications of seleninate esters because of the possibility of catalyzing the unwanted oxidation of disulfide-containing spectator peptides and proteins. A variety of aryl and alkyl disulfides underwent facile oxidation with hydrogen peroxide in the presence of catalytic benzo-1,2-oxaselenolane Se-oxide affording the corresponding thiolsulfinates as the principal products. Unsymmetrical disulfides typically afforded mixtures of regioisomers. Lipoic acid and N,N′-dibenzoylcystine dimethyl ester were oxidized readily under similar conditions. Although isolated yields of the product thiolsulfinates were generally modest, these experiments demonstrate that the method nevertheless has preparative value because of its mild conditions. The results also confirm the possibility that cyclic seleninate esters could catalyze the further undesired oxidation of disulfides in vivo.
- McNeil, Nicole M. R.,McDonnell, Ciara,Hambrook, Miranda,Back, Thomas G.
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p. 10748 - 10762
(2015/08/11)
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- Silica-coated magnetite nanoparticles stabilized simple Mn-tetraphenylporphyrin for aqueous phase catalytic oxidations with tert-butyl hydroperoxide
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An economic and environmentally friendly system for efficient and selective oxidation of industrially and biologically important substrates in water using tert-butyl hydroperoxide catalyzed by a new magnetically recoverable Mn-porphyrin was developed. The easily prepared heterogeneous catalyst was characterized by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, FT-IR and UV-vis spectroscopy. The size of the catalyst was estimated to be about 10 nm. The thermal gravimetric analysis demonstrated that the nanocatalyst was thermally stable up to almost 300 °C. The reactivity, selectivity and scope of the reaction were investigated with a variety of olefins, saturated hydrocarbons, alcohols and organosulfur compounds. The reactions proceeded smoothly in the absence of surfactants, organic co-solvents and thus take place "on water". The separation and recycling of nanocatalyst as well as isolation of water-insoluble products were simple, effective and economical in this clean oxidation method.
- Rezaeifard, Abdolreza,Farshid, Parisa,Jafarpour, Maasoumeh,Moghaddam, Gholamreza Kardan
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p. 9189 - 9196
(2014/03/21)
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- The sila-Pummerer reaction of γ-silyl substituted cycloalkanoyl sulfoxides: The first examples and a new approach to 3-substituted cycloalk-2-enones
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The thermal decomposition of 3-(α-trimethylsilyl)alkyl substituted 2-(phenylsulfinyl)cycloalkanones occurs via the γ-sila-Pummerer reaction, affording 3-substituted cycloalk-2-enones and unstable trimethylsilyl benzenesulfenate as an elimination by-product. The starting γ-silyl substituted cycloalkanoyl sulfoxides were obtained through the conjugate addition reaction of nucleophilic reagents to 2-(phenylsulfinyl)cycloalk-2- enones. The tandem conjugate addition/γ-sila-Pummerer reaction investigated here provides a new route to 3-substituted cycloalk-2-enones.
- Mikina, Maciej,Miko?ajczyk, Marian
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p. 3954 - 3956
(2014/07/08)
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- The first observation of γ-sila-pummerer rearrangement
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2-Sulfinyl-3-trimethylsilylmethylcycloalkanones unexpectedly undergo γ-sila-Pummerer rearrangement. The first examples of this new type of rearrangement are presented.
- Mikina, Maciej
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p. 454 - 458
(2013/07/26)
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- Structural effects on the C-S bond cleavage in aryl tert -butyl sulfoxide radical cations
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The oxidation of a series of aryl tert-butyl sulfoxides (4-X-C 6H4SOC(CH3)3: 1, X = OCH 3; 2, X = CH3; 3, X = H; 4, X = Br) photosensitized by 3-cyano-N-methylquinolinium perchlorate (3-CN-NMQ+) has been investigated by steady-state irradiation and nanosecond laser flash photolysis (LFP) under nitrogen in MeCN. Products deriving from the C-S bond cleavage in the radical cations 1+?-4+? have been observed in the steady-state photolysis experiments. By laser irradiation, the formation of 3-CN-NMQ? (λmax = 390 nm) and 1 +?-4+? (λmax = 500-620 nm) was observed. A first-order decay of the sulfoxide radical cations, attributable to C-S bond cleavage, was observed with fragmentation rate constants (k f) that decrease by increasing the electron donating power of the arylsulfinyl substituent from 1.8 × 106 s-1 (4 +?) to 2.3 × 105 s-1 (1 +?). DFT calculations showed that a significant fraction of the charge is delocalized in the tert-butyl group of the radical cations, thus explaining the small substituent effect on the C-S bond cleavage rate constants. Via application of the Marcus equation to the kinetic data, a very large value for the reorganization energy (λ = 62 kcal mol-1) has been calculated for the C-S bond scission reaction in 1+?-4 +?.
- Cavattoni, Tullio,Del Giacco, Tiziana,Lanzalunga, Osvaldo,Mazzonna, Marco,Mencarelli, Paolo
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p. 4886 - 4894
(2013/07/11)
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- A traceless, one-pot preparation of unsymmetric disulfides from symmetric disulfides through a repeated process involving sulfenic acid and thiosulfinate intermediates
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A variable group of unsymmetric disulfides was prepared under mild reaction conditions and in high yields through the reaction of symmetric disulfides with sulfuryl chloride followed by treatment with thiols in the presence of water.
- Han, Minsoo,Lee, Jong Tak,Hahn, Hoh-Gyu
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supporting information; experimental part
p. 236 - 239
(2011/02/28)
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- Photosensitized oxidation of alkyl phenyl sulfoxides. C-S bond cleavage in alkyl phenyl sulfoxide radical cations
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(Chemical Equation Presented) The 3-cyano-N-methylquinolinium Perchlorate (3-CN-NMQ+ ClO4-)-photosensitized oxidation of phenyl alkyl sulfoxides (PhSOCR1R2R3,1, R1 = R2 = H, R3 = Ph; 2, R1 = H, R2 = Me, R3 = Ph; 3, R1 = R2 = Ph, R3 = H; 4, R1 = R2 = Me, R3 = Ph; 5, R1 = R2 = R3 = Me) has been investigated by steady-state irradiation and nanosecond laser flash photolysis (LFP) under nitrogen in MeCN. Steady-state photolysis showed the formation of products deriving from the heterolytic C-S bond cleavage in the sulfoxide radical cations (alcohols, R 1R2R3COH, and acetamides, R1R 2R3CNHCOCH3) accompanied by sulfur-containing products (phenyl benzenethiosulfinate, diphenyl disulfide, and phenyl benzenethiosulfonate). By laser irradiation, the formation of 3-CN-NMQ ? (λmax = 390 nm) and sulfoxide radical cations 1?+, 2?+, and 5?+ (λmax = 550 nm) was observed within the laser pulse. The radical cations decayed by first-order kinetics with a process attributable to the heterolytic C-S bond cleavage leading to the sulfinyl radical and an alkyl carbocation. The radical cations 3?+ and 4?+ fragment too rapidly, decaying within the laser pulse. The absorption band of the cation Ph2CH+ (λmax = 440 nm) was observed with 3 while the absorption bands of 3-CN-NMQ? and PhSO? (λmax = 460 nm) were observed just after the laser pulse in the LFP experiment with 4. No competitive β-C-H bond cleavage has been observed in the radical cations from 1-3. The C-S bond cleavage rates were measured for 1?+, 2?+, and 5?+. For 3?+ and 4?+, only a lower limit (ca. >3 × 107 s-1) could be given. Quantum yields (Φ) and fragmentation first-order rate constants (k) appear to depend on the structure of the alkyl group and on the bond dissociation free energy (BDFE) of the C-S bond of the radical cations determined by a thermochemical cycle using the C-S BDEs for the neutral sulfoxides 1-5 obtained by DFT calculations. Namely, Φ and k increase as the C-S BDFE becomes more negative, that is in the order 1 ?+ (1.4 × 106 s-1) with the upper limit (104 s-1) given for fert-butyl phenyl sulfide radical cation (Baciocchi, E.; Del Giacco, T.; Gerini, M. F.; Lanzalunga, O. Org. Lett. 2006, 8, 641-644). It turns out that sulfoxide radical cations undergo C-S bond breaking at a rate at least 2 orders of magnitude faster than that of corresponding sulfide radical cations.
- Baciocchi, Enrico,Del Giacco, Tiziana,Lanzalunga, Osvaldo,Mencarelli, Paolo,Procacci, Barbara
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p. 5675 - 5682
(2008/12/22)
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- Selective oxidation of sulfides to sulfoxides and sulfones at room temperature using H2O2 and a Mo(VI) salt as catalyst
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Selective oxidation of sulfides to sulfoxides and sulfones is achieved by H2O2 using MoO2Cl2 as the catalyst. Various substituted sulfides having functional groups such as methyl, methoxy, bromo, nitro, alkene, alkyne, alcohol, ester, aldehyde and remarkably an oxime are successfully and selectively oxidized without affecting the sensitive functionalities.
- Jeyakumar, Kandasamy,Chand, Dillip Kumar
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p. 4573 - 4576
(2007/10/03)
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- Serial ligand catalysis: A highly selective allylic C-H oxidation
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We are reporting a mild, chemo-, and highly regioselective Pd(II)-catalyzed allylic oxidation of α-olefins to furnish branched allylic esters that proceeds via a novel serial ligand catalysis mechanism in which two different ligands (i.e., vinyl sulfoxide 2 and BQ) interact sequentially with the metal to promote distinct steps of the catalytic cycle (i.e., C-H cleavage and π-allyl functionalization, respectively). Copyright
- Chen, Mark S.,Prabagaran, Narayanasamy,Labenz, Nathan A.,White, M. Christina
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p. 6970 - 6971
(2007/10/03)
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- Highly efficient utilization of H2O2 for oxygenation of organic sulfides catalyzed by [γ-SiW10O34(H 2O)2]4-
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Remarkable efficiency of hydrogen peroxide utilization is reported for oxygenation of four organic sulfides catalyzed by a divacant lacunary silicotungstate, (Bu4N)4[γ-SiW10O 34(H2O)2] (1), under mild conditions. The addition of imidazole, phosphate, or carboxylates significantly enhances the rate of organic sulfide oxygenation. Most notably, use of 1 and imidazole, both at 1% molar concentration, resulted in the quantitative conversion of phenylsulfide to sulfoxide with 1 equiv of H2O2 in 3 h, and to sulfone with 2 equiv of H2O2 in 6 h.
- Phan, Tuan D.,Kinch, Mark A.,Barker, Julia E.,Ren, Tong
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p. 397 - 400
(2007/10/03)
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- Facile oxygenation of organic sulfides with H2O2 catalyzed by Mn-Me3TACN compounds
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Two binuclear Mn-Me3TACN (Me3TACN is 1,4,7-N,N′,N″-trimethyl-1,4,7-triazacyclononane) compounds catalyze the oxygenation of organic sulfides utilizing H2O2 under ambient conditions. Both phenyl sulfide and ethyl phenyl sulfide were converted to the corresponding sulfones and chloroethyl phenyl sulfide proceeds to its elimination product of phenyl vinyl sulfone.
- Barker, Julia E.,Ren, Tong
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p. 4681 - 4683
(2007/10/03)
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- S-(4-methoxyphenyl) benzenethiosulfinate (MPBT)/ trifluoromethanesulfonic anhydride: A convenient system for the generation of glycosyl triflates from thioglycosides
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(Matrix presented) The combination of S-(4-methoxyphenyl) benzenethiosulfinate (MPBT, 1) and trifluoromethanesulfonic anhydride forms a powerful, metal-free, thiophile which readily activates thioglycosides, via glycosyl triflates, at -60°C in dichloromet
- Crich, David,Smith, Mark
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p. 4067 - 4069
(2007/10/03)
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- Photolysis of Alkyl Aryl Sulfoxides: α-Cleavage, Hydrogen Abstraction, and Racemization
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The photochemistry of a series of alkyl aryl sulfoxides is described. The initial event of the photolysis process is homolytic cleavage to form sulfinyl/alkyl radical pairs. The radical pair partitions between recombination to starting material, formation of sulfenic esters, disproportionation to an olefin and benzenesulfenic acid, and formation of typical radical escape products. The quantum yield for conversion depends on the structure or the reactivity of the alkyl radical, with the sequence benzyl > tertiary alkyl > secondary alkyl > primary alkyl > (di)aryl. The high racemization efficiency of some aryl primary-alkyl sulfoxides suggests that another nonradical pathway for the photoracemization process may exist. Product analysis does not support any hydrogen abstraction pathways.
- Guo, Yushen,Jenks, William S.
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p. 857 - 864
(2007/10/03)
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- SULFENAMIDES AND SULFINAMIDES X OXIDATION OF THIOLS BY ARYL SULFINAMIDES
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A dissection has been made of the oxidation of thiols by aryl sulfinamides, with the process explained by initial protonation of the sulfinyl group followed by a series of nucleophilic displacements, the first of which gives thiosulfinate and elimination of amine.The more usual reaction with thiosulfinate then gives disulfide, and sulfenic acid as a transitory intermediate, which by reaction with a third mole of thiol yields more disulfide.Reactions with lesser amounts of thiol permitted identification of intermediates.The effect of activation of the thiol isdiscussed.In contrast with oxidations by simpler sulfoxides the reaction proceeds without acid catalysis at ambient temperature, confirming the susceptibility to fission of the S-N bond in polar reactions.Key words: Sulfinamide, sulfenamide, thiol, fission, nucleophilic displacement, disulfide.
- Clarke, Victor,Cole, Edward R.
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- Method and composition for the treatment of imflammatory conditions using thiosulphinic acid derivatives
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The invention concerns thiosulphinic acid derivatives, medicaments containing these compounds and their use in medicine. It has been found that thiosulphinic acid derivatives display outstanding inflammation-inhibiting properties. The compounds prove to b
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- Dual Reactivity of Methoxymethyl Benzenesulfonate in Nucleophilic Substitution
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Hydrolysis of methoxymethyl benzenesulfenate is catalyzed by both acid and base.Acid-catalyzed hydrolysis is further accelerated by various nucleophiles like halide ions, thiocyanate, dialkyl sulfide, and the substrate itself.The catalytic constants coincide with those for ethyl benzenesulfenate within 2-fold in magnitude.The nucleophilic reactivity strongly suggests the reaction at the sulfenyl sulfur, but examination of the products from the 18O-labeled substrate showed that the bond cleavage occurs mostly between the oxygen and the proformyl carbon except for the acid-catalyzed water reaction which undergoes the S-O cleavage.A mechanism for a nucleophilic reaction at the sulfur to form a sulfurane intermediate which breaks down with the C-O cleavage is presented.The hydrolysis rate is also strongly dependent on the second order of buffer concentrations in carboxylate and tertiary amine buffer solutions.The third-order term involves both the general acid and the conjugate base of the buffer, and the latter reacts at the sulfur as a nucleophile in the rate-determining step but leads to the C-O cleavage in the same way as the other catalytic nucleophiles.
- Okuyama, Tadashi,Fueno, Takayuki
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p. 2672 - 2683
(2007/10/02)
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- CO-OXIDATIONS OF SQUALENE WITH DISULFIDES AND THIOSULFINATES
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Comparison of the activities of alkyl and aryl disulfides in inhibiting the autoxidation of squalene show the greater efficiency of the alkyl derivatives.The effect of electron donating substituents in aryl derivatives, promoting efficiency in the order CH3O > CH3 > H, is reversed in the thiosulfinates when added directly, although they are considered to be inhibitors formed in situ from the disulfides.The anomaly is discussed in terms of rates of oxidation and stabilities of the oxidation products and leads to the concept of thiosulfinate/disulfide mixture as a more efficient antioxidant.Key words: Antioxidants; disulfides; thiosulfinates; sulfinyl group; stability.
- Cole, Edward R.
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p. 147 - 160
(2007/10/02)
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- The Claisen Rearrangement of 2-Phenylsulfinyl-2-propenyl Phenyl Ethers - A New Route to Functionalized Phenols and 2-Methylbenzofurans
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The hitherto unknown Claisen rearrangement of 2-phenylsulfinyl-2-propenyl phenyl ethers to the corresponding 2-(2-phenylsulfinyl-2-propenyl)phenols is reported.The latter compounds underwent Michael reactions with a variety of nucleophiles to provide functionalized phenolic adducts.O-Alkylation of the initial rearrangement products with 3-bromo-2-phenylsulfinyl-1-propene and 2,3-dibromo-1-propene followed by sigmatropic rearrangement provided a promising route to 7-substituted 2-methylbenzofurans.
- Khan, Muhammad Akram
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p. 3682 - 3686
(2007/10/02)
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- PHOTOINDUCED GENERATION OF GLYCOSYL CATIONS FROM THIOGLYCOSIDES
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Photochemically induced cleavage of thioaryl β-D-glucopyranosides using 1,4-dicyanonaphthalene as an electron-transfer agent, produces glycosyl cations potentially useful in glycosylation reactions.
- Griffin, Gary W.,Bandara, Nayanie C.,Clarke, Margaret A.,Tsang, Wing-Sum,Garegg, Per J.,et al.
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p. 939 - 947
(2007/10/02)
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- Mechanism of Second-Order Buffer Catalysis in the Hydrolysis of Methoxymethyl Benzenesulfenate
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Hydrolysis of methoxymethyl benzenesulfenate is catalyzed by both acid and base.Rates depend on a second order of buffer concentration, which results from general acid-promoted nucleophilic attack by the base at the proformyl carbon.
- Okuyama, Tadashi,Gandour, Richard D.,Fueno, Takayuki
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p. 273 - 276
(2007/10/02)
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- Acid-Catalyzed Cleavage of Methoxymethyl Phenyl Sulfoxide. Solvent Effects and Mode of Bond Cleavage
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Rate constants for the acid-catalyzed hydrolysis of methoxymethyl phenyl sulfoxide increase with increasing composition of dioxane in dioxane aqueous solution in contrast to the isomeric sulfenate which is strongly decelerated by added dioxane fraction (u
- Okuyama, Tadashi,Fueno, Takayuki
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p. 3111 - 3116
(2007/10/02)
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- Nucleophilic Catalysis in the Hydrolysis of Methoxymethyl Benzenesulfenate, a Formaldehyde Acetal
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Acid-catalyzed hydrolysis of methoxymethyl benzenesulfenate is accelerated by nucleophiles (Cl-, Br-, I-, R2S, AcO-, tertiary amines, and the substrate itself) through the attack at the proformyl carbon while water attacks at the sulfenyl sulfur.
- Okuyama, Tadashi,Fueno, Takayuki
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p. 2193 - 2196
(2007/10/02)
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- Chemistry of Sulfenic Acids. 7. Reason for the High Reactivity of Sulfenic Acids. Stabilization by Intramolecular Hydrogen Bonding and Electronegativity Effects
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It is proposed that the reason sulfenic acids (RSOH) are so reactive and usually not isolated or even detected is that they form thiosulfinates (RS(O)SR) so readily.This is a consequence of the sulfenic acid hydrogen-bonded dimer, 1, which lowers the energy of activation for thiosulfinate formation.The stability of the few sulfenic acids that have been isolated can be explained in terms of steric, electronic, and intramolecular hydrogen-bonding effects which prevent dimer formation.The importance of these effects on the stability of simple unstable sulfenic acids was demonstrated by flash vacuum pyrolysis (FVP) and the thiosulfinate/vinyl sulfoxide ratio.A novel, high yield, rearrangement of sulfenic acid 19f to 1,3-benzothiazine 26 was observed.
- Davis, Franklin A.,Jenkins, Linda A.,Billmers, Robert L.
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p. 1033 - 1040
(2007/10/02)
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- Formation of Elusive vic-Disulfoxides and OS-Sulfenyl Sulfinates during the m-Chloroperoxybenzoic Acid (MCPBA) Oxidation of Alkyl Aryl Disulfides and Their Regioisomeric Sulfinothioic Acid S-Esters
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The initial step in the 1 equiv m-chloroperoxybenzonic acid (MCPBA) oxidation of 2,2-dimethylpropyl phenyl disulfide (10) and phenyl phenylmethyl disulfide (14) occurs predominantly at the sulfur atom bonded to the alkyl group to give S-phenyl 2,2-dimethylpropanesulfinothioate (5) and S-phenyl phenylmethanesulfinothioate (6), respectively.The 2 equiv MCPBA oxidation of disulfide 10 gives S-phenyl 2,2-dimethylpropanesulfonothioate (23) as the major product.The 1 equiv MCPBA oxidation of thiosulfinates 5 and 6 and S-2,2-dimethylpropyl benzenesulfinothioate (9) ultimately gives thiosulfonate 23, S-phenyl phenylmethanesulfonothioate (17), and thiosulfonate 23, respectively, as the major products.Thus, peroxidation of regioisomeric S-alkyl and S-aryl sulfinothioates 5 and 9 occurs predominantly at the sunfenyl sulfur atom to give diastereomeric vic-disulfoxides (α-disulfoxides) which may undergo cycloelimination to sulfines and sulfenic acids, dissociate to sulfinyl radicals, and rearrange intramoleculary to OS-sulfenyl silfinates and/or to sulfonothioic acid S-esters.OS-Sulfenyl sulfinates may isomerize to sulfonothioic acid S-esters or dissociate to sulfinyl radicals and/or to thiyl and sulfonyl radicals.The sulfinyl radicals may combine to form vic-disulfoxides and/or OS-sulfenyl sulfinates while the thiyl and sulfonyl radicals may lead to sulfonothioic acid S-esters.
- Freeman, Fillmore,Angeletakis, Christos N.
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p. 793 - 798
(2007/10/02)
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- Reaction of Benzenesulfinyl Azide with Thiols and Amines. Preparation of Thiosulfinates and Sulfinamides
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Reaction of benzenesulfinyl azide (1) with thiols at -20 deg C gave thiosulfinates and hydrazoic acid.Reaction of 1 with primary and secondary amines gave sulfinamides and hydrazoic acid.The presence of a hydroxyl group in the thiol or amine did not change the course of the reaction.Thus, a thiosulfinate and sulfinamide containing a free hydroxyl group could be prepared.Yields ranging from 41percent to 93percent were obtained.
- Maricich, Tom J.,Angeletakis, Christos N.
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p. 1931 - 1934
(2007/10/02)
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- LIGAND COUPLING THROUGH ?-SULFURANE --- COMPLETE RETENTION OF CONFIGURATION OF 1-PHENYLETHYL GROUP IN THE REACTION OF 1-PHENYLETHYL 2-PYRIDYL SULFOXIDE WITH GRIGNARD REAGENT
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The reaction of benzyl or 1-phenylethyl 2-pyridyl sulfoxide with Grignard reagent proceeds via a ?-sulfurane as an intermediate to give the coupling product, 2-benzylpyridine or 2-(1-phenylethyl)pyridine in quantitative yield.Stereochemistry for this reaction is complete retention at the benzylic carbon atom.
- Oae, Shigeru,Kawai, Tsutomu,Furukawa, Naomichi
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- A GENERAL, HIGH-YIELD PREPARATION OF THIOSULFINATE ESTERS USING ORGANOTIN PRECURSORS
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A variety of thiosulfinate esters are produced in >90percent isolated yield by the reaction of organotin thiolates with sulfinyl chlorides.
- Harpp, David N.,Aida, T.,Chan, T. H.
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p. 5173 - 5176
(2007/10/02)
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- Chemistry of Sulfenic Acids. 3. Studies of Sterically Hindered Sulfenic Acids Using Flash Vacuum Pyrolysis
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Flash vacuum pyrolysis (FVP) of sulfoxides containing β-hydrogen atoms affords sulfenic acids (RSOH) in good concentration under conditions where they are stable.The application of this technique to the synthesis and study of sterically hindered sulfenic acids 12a-e is described.The principal or primary reaction of simple sulfenic acids prepared in this manner is dehydration to thiosulfinates 13 (eq 1).Steric inhibition to dehydration (eq 1) appears to only be of importance for 2-methyl-2-propanesulfenic acid (12a) which was trapped in good yield with methyl propiolate to afford 16a. 2,4,6-Tri-tert-butylbenzenesulfenic acid (12e) appears to be destabilized as a consequence of interaction between the SOH and adjacent tert-butyl groups.In the pyrolysis section of the apparatus, 12e decomposes to phenol 21 and aryl radical 22, which reacts further.Thermolysis of sulfoxides generates the sulfenic acids 12a-e in very low concentration at any one time.The products of sulfenic acids generated in this way result from secondary reactions of the corresponding thiosulfinates.
- Davis, Franklin A.,Jenkins, Robert H.,Rizvi, Syed Q. A.,Yocklovich, Steven G.
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p. 3467 - 3474
(2007/10/02)
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- Intermediates in the Peroxy Acid Oxidation of Phenyl Phenylmethanethiosulfinate
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The m-chloroperoxybenzoic acid (MCPBA) oxidation of phenyl phenylmethanethiosulfinate (9) in CDCl3 has been studied.Low-temperature 1H NMR and 13C NMR spectra show that phenyl phenylmethanethiosulfonate (7), phenylmethanesulfonic acid (26), and phenylmethanesulfinic acid (27) are formed during the early stages of oxidation.Although 7 may be formed via direct attack of MCPBA at the sulfinyl sulfur atom of 9, the presence of 7, 26, and 27 is also explicable in terms of formation and rearrangement of metastable α-disulfoxide (13) and sulfenyl sulfinate (14) intermediates.
- Freeman, Fillmore,Angeletakis, Christos N.
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p. 3991 - 3996
(2007/10/02)
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- Preparation and Trapping of Sulphenic Acids
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Benzene- and toluene-α-sulphenic acids have been prepared under mild conditions from 4-benzenesulphinyl- and 4-toluene-α-sulphinyl-4-methylpentan-2-one respectively.The acids were trapped with norbornadiene.
- Barrett, Anthony G.M.,Barton, Derek H.R.,Nagubandi, Sreemulu
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p. 237 - 239
(2007/10/02)
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