- Palladium catalyzed synthesis of aryl thiols: Sodium thiosulfate as a cheap and nontoxic mercapto surrogate
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A Pd-catalyzed coupling reaction of ArBr/ArCl/ArOTf with sodium thiosulfate takes place in presence of Cs2CO3 at 80 °C. The reaction mixture is directly treated with Zn/HCl to afford aryl thiols in good to excellent yields.
- Yi, Jun,Fu, Yao,Xiao, Bin,Cui, Wei-Chen,Guo, Qing-Xiang
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experimental part
p. 205 - 208
(2011/02/26)
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- Copper-catalyzed coupling of thiourea with aryl iodides: The direct synthesis of aryl thiols
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A general, economical and efficient protocol for the direct copper-catalyzed coupling of thiourea with aryl iodides is developed and it will be potentially applied in large-scale industry as a preferred process.
- Qiao, Shu,Xie, Kun,Qi, Junsheng
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scheme or table
p. 1441 - 1443
(2011/01/04)
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- A general and efficient approach to aryl thiols: Cul-catalyzed coupling of aryl iodides with sulfur and subsequent reduction
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A Cul-catalyzed coupling reaction of aryl iodides and sulfur powder takes place in the presence of K2CO3 at 90 °C. The coupling mixture is directly treated with NaBH4 or triphenylphosphine to afford aryl thiols in good to
- Jiang, Yongwen,Qin, Yuxia,Xie, Siwei,Zhang, Xiaojing,Dong, Jinhua,Ma, Dawei
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supporting information; scheme or table
p. 5250 - 5253
(2009/12/28)
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- Resin and its use in converting morphine to codeine
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A resin and its use as a methylating agent. One embodiment is a resin comprising a solid support and cationic methylated sulfonium, sulfoxonium, selenonium or phosphonium salts immobilized on the solid support. Another embodiment is the use of the resin as a methylating agent, for example in the conversion of morphine to codeine.
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- Aromatic thioether acylation method
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PCT No. PCT/FR96/01763 Sec. 371 Date Aug. 3, 1998 Sec. 102(e) Date Aug. 3, 1998 PCT Filed Nov. 8, 1996 PCT Pub. No. WO97/17324 PCT Pub. Date May 15, 1997The present invention relates to a process for the acylation of an aromatic thioether. In its preferred variant, the invention resides in a process for the condensation of acetic anhydride or acetyl chloride with thioanisole. The process for the acylation of an aromatic thioether according to the invention is characterised in that it consists in reacting said thioether with an acylating agent chosen from the group formed by the halides of carboxylic acids and the anhydrides of carboxylic acids, in the presence of an effective quantity of an acid zeolite.
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- Thiol radical cations and thiyl radicals as direct products of the free electron transfer from aromatic thiols to n-butyl chloride radical cations
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Radical and ionic reactions were observed in the pulse radiolysis of thiophenols (ArSH = thiophenol, o-, m- and p-thiocresol or 2-thionaphthol) in n-butyl chloride solution. The main source of aromatic thiyl radicals is the reaction of butyl radicals with the thiols, which proceeds at 1.0-5.6 x 108 dm3 mol-1 s-1. This radical generation path is completely quenched in the presence of oxygen. Under these conditions, only the electron transfer reaction between n-butyl chloride parent ions and the thiophenols remains and could be well analyzed. It takes place at a rate constant of about 1.5 x 1010 dm3 mol-1 s-1 and takes two parallel paths-common electron transfer yielding thiophenol radical cations and a more complex ionic reaction resulting directly in thiyl radicals. The latter is thought to proceed via an encounter complex geometry, ArSH···ClBu.+, in which electron transfer is directly followed by immediate deprotonation. The thiyl radicals and the thiol radical cations are characterized by their optical absorption spectra and their kinetic properties. Quantum chemical calculations underpin our mechanistic interpretation and provide information about the charge distribution and reactivity of the thiol radical cations.
- Hermann, Ralf,Dey, Ghasi Ram,Naumov, Sergej,Brede, Ortwin
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p. 1213 - 1220
(2007/10/03)
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- Oxidative cleavage of S-Arylmercaptoacetic acids by pyridinium chlorochromate: Kinetic and correlation analysis
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Kinetics of oxidation of 24 S-Arylmercaptoacetic acids (SAMA) by pyridinium chlorochromate (PCC) have been studied in acid medium. The product of oxidation is the corresponding thiophenol. The rate data of meta- and para-substituted acids have been correlated well with σI, σ°R values and the meta-compounds correlate well with F,R values. The reaction constants are negative and of smaller magnitudes. Further, the ortho-substituted acids show a good correlation with triparametric equation involving Taft's σI and σ°R and charton's steric parameter v. There is no considerable steric contribution to the total orthosubstituent effect. Based on these observations, the mechanism involving the formation of protonated arylsulfinylacetic acid intermediate, followed by an intramolecular rearrangement leading to the product thiophenol has been proposed.
- Kabilan,Girija,Rajagopal
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p. 683 - 688
(2007/10/03)
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- Phenylthio-derivatives of α-methylene-γ-lactones as pro-drugs of cytotoxic agents
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A series of substituted phenylthio-derivatives of grosheimin (1), a natural cytotoxic guaianolide, were investigated with the aim of providing insight into their mechanism of action as cytotoxic agents against KB cell lines. Hydrolysis data, kinetics, in the presence and in the absence of H2O2, and the valuation of lipophilicity were correlated with cytotoxicity values and with Hammett-σ-values of substituents (R) at the thiophenol ring. These compounds behave as 'pro-drugs' which release the cytotoxic agent grosheimin by sulphur-oxidation promoted by H2O2 and subsequent retro- elimination which depends on the nature and position of the R substituent.
- Fardella, Giuseppe,Barbetti, Paolo,Grandolini, Giuliano,Chiappini, Ione,Ambrogi, Valeria,Scarcia, Vito,Furlani Candiani, Ariella
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p. 515 - 523
(2007/10/03)
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- Modified Borohydride Agents, 1-Benzyl-4-aza-1-azoniabicyclooctane Tetrahydroborate (BAAOTB) versus Tetrabutylammonium Tetrahydroborate (TBATB). Efficient, Selective, and Versatile Reducing Agents
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1-Benzyl-4-aza-1-azoniabicyclooctane tetrahydroborate (BAAOTB) and tetrabutylammonium tetrahydroborate (TBATB) are used for the selective reductions of aldehydes, ketones, α,β-unsaturated carbonyl compounds, acid chlorides, azides, epoxides, and disulfides in t-BuOH and hexane/chloroform.ABBOAB with its rigid and bulky structure reacts more selectively than its analogue TBATB.
- Firouzabadi, Habib,Afsharifar, Gholam Reza
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p. 2595 - 2602
(2007/10/03)
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- Oxidative Cleavage of S-Arylmercaptoacetic Acids by Sodium Perborate: Kinetic and Correlation Study
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Kinetics of oxidation of twenty six S-arylmercaptoacetic acids (SAMA) (I) by sodium perborate (PB) have been studied in acid medium.The product of oxidation is the corresponding thiophenol.The rate data of meta- and para-substituted acids have been correlated with DSP equations.While the para-compounds correlate well with ?I and ?0R values, the meta-compounds correlate well with ?I and ?-R values.The reaction constants are negative and of smaller magnitudes.Further, the ortho-substituted acids show a good correlation with a triparametric equation involving Taft's ?I and ?0R and Charton's steric parameter ν.There is a considerable steric contribution to the total ortho-substituent effect.Based on these observations, mechanism involving the formation of protonated arylsulfinylacetic acid intermediate, followed by an intramolecular rearrangement leading to the product thiophenol has been proposed.
- Kabilan, S.,Pandiarajan, K.,Krishnasamy, K.,Sankar, P.
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p. 443 - 452
(2007/10/02)
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- THE REACTION BETWEEN ARENEDIAZONIUM TETRAFLUOROBORATES AND ALKALINE THICARBOXYLATES IN DMSO: A CONVENIENT ACCESS TO ARYL THIOLESTERS AND OTHER AROMATIC SULFUR DERIVATIVES.
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The reaction between potassium thioacetate or sodium thiobenzoate and arenediazonium tetrafluoroborates in DMSO leads to the corresponding aryl thiolesters 1 which can either be isolated or further reacted providing a convenient one-pot access to a number of other aromatic sulfur derivatives.
- Petrillo, Giovanni,Novi, Marino,Garbarino, Giacomo,Filiberti, Marcos
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p. 7411 - 7420
(2007/10/02)
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- The Reaction of Alkyl-substituted Thioanisoles with PCl3 and AlCl3: a Route to Benzothiadiphospholobenzothiadiphosphole Derivatives
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The synthesis of benzothiadiphospholobenzothiadiphosphole derivatives starting from alkyl-substituted thioanisoles and PCl3-AlCl3 is reported.The reaction is carried out at reflux in the absence of solvent and the yields are dependent on the starting sulphide.These new heterocycles can be purified by simple filtration on a Florisil column and have been characterized by 1H-, 13C-, (1H)31P-n.m.r. and mass spectroscopy analyses.New unexpected findings are also described.
- Baccolini, Graziano,Mezzina, Elisabetta,Todesko, Paolo Edgardo
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p. 3281 - 3284
(2007/10/02)
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- SYNTHESIS AND CONFIGURATIONAL STUDIES OF ARYL CYCLOPROPYL SULFONES
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The cycloaddition of arylthiocarbenes to styrene gave stereospecifically cis-1-(arylthio)-2-phenylcyclopropanes, which were subsequently oxidized to the corresponding sulfones.The cyclopropanation of α,β-unsaturated sulfones with dimethylsulfonium methylide yielded stereoselectively trans-1-(arylsulfonyl)-2-arylcyclopropanes.The configurational assignments of these compounds have been arrived at on the basis of IR and PMR spectral data.Chemical shifts for ring protons and other substituents reveal that all the substituents tend to cause protons cis to them to appear at higher fields than those trans to them.This has been used as a criterion to distinguish between cis and trans aryl cyclopropyl sulfones.
- Reddy, D. Bhaskar,Balaji, T.,Reddy, B. Venkataramana
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p. 297 - 306
(2007/10/02)
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- Antimicrobial composition and method containing N-(3,5-dihalophenyl)-imide compounds
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Novel N-(3,5-dihalophenyl)imide compounds, which exhibit a strong antimicrobial activity against microorganisms including phytopathogenic fungi, parasites of industrial products and pathogenic microorganisms, represented by the formula, STR1 wherein X and X' each represent halogens and A represents a substituted ethylene such as chloroethylene, C1 - C4 alkylthioethylene, C1 - C2 alkyl-ethylene or 1,2-di-C1 - C2 -alkyl-ethylene, a cyclopropylene such as 1,3-dimethylcyclopropylene, trimethylene, a cyclohexylene-1,2-, cyclohexenylene-1,2-, cyclohexadienylene-1,2- or o-phenylene. The N-(3,5-dihalophenyl)imide compounds can be obtained by any of methods which produce imide compounds or reaction of an N-(3,5-dihalophenyl)maleimide compound with a mercaptan, a hydrogen halide, phosphorus chloride or thionylchloride.
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