- Kinetic support for the generation of a phenylsulfenium ion intermediate
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In the reaction of N-methylbenzenesulfenamide (1) with thioanisole (4) in the presence of trifluoroacetic acid (TFA), the initial rate υ0 of total appearance of 2- and 4-(methylthio)phenyl phenyl sulfides (5) is first and zero order with respect to the initial concentrations of 1 and 4, respectively: υ0=kobs[1]0. The pseudo-first order rate constant kobs is evaluated as 5.2×10-4 sec-1 with varying concentrations of 4 (0.72 to 5.0 M) in a mixture of 4 and CH2Cl2 in the presence of TFA at 10 °C. This data supports the notion that a phenylsulfenium ion intermediate 3 interacting with both the counter ion and the unshared electron-pair of amine is generated by heterolytic N-S scission of the protonated sulfenamide 2, leading to the observed formation of 5.
- Takeuchi, Hiroshi,Tateiwa, Jun-Ichi,Moriguchi, Shintaro
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Read Online
- Electrochemical Formation and Activation of Hydrogen Peroxide from Water on Fluorinated Tin Oxide for Baeyer-Villiger Oxidation Reactions
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The two-electron oxidation of water (2e-WOR) has been studied in the past as a possible method for the alternative preparation of hydrogen peroxide. Often, fluorinated tin oxide (FTO) is used as an anode and FTO itself was found also to be active for 2e-WOR. Because one use of H2O2is as an oxygen donor for Baeyer-Villiger oxidation of ketones catalyzed by tin compounds and materials, presently we were interested in studying the use of in situ formed H2O2for these reactions. First, the formation of H2O2was verified in an acetonitrile/water solvent in a 2e-WOR reaction, which is more efficient than a comparable reaction in water in terms of the H2O2concentration attained and faradaic efficiency at comparable potentials, that is, ~3 V vs SHE. Second, initial studies on oxygenation of reactive substrates such as sulfides showed normalized reaction rates (NRRs) for two-electron oxidation reactions that were about 3 times higher than the NRR for H2O2formation, indicating the formation of an active oxygen-donating or oxidizing species on the electrode surface prior to the formation and release of H2O2into solution. Third, the Baeyer-Villiger oxygenation of 2-adamantanone at 2.1 V versus SHE in acetonitrile/water showed both the formation of the expected lactone product and hydroxylation at both tertiary and secondary C-H bonds. Hydroxylation is most easily explained by the presence of hydroxyl radical species as supported by the formation of a spin adduct and its identification by electron paramagnetic resonance. However, the potential used, 2.1 V versus SHE, is an underpotential for the formation of a solvated hydroxyl radical in solution, thereby leading to the conclusion that surface-bound hydroxyl species, OH*, are those that are reactive for the apparent one-electron water oxygenation reaction. Fourth, it was shown that although H2O2can be thermally activated on FTO as a catalyst to a minor degree, electrochemical activation is by far more significant, leading to the use of FTO as an electrochemical catalyst for activation of H2O2for the Baeyer-Villiger oxygenation and also alkene epoxidation.
- Herman, Adi,Mathias, Jenny-Lee,Neumann, Ronny
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p. 4149 - 4155
(2022/04/12)
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- Chan-Lam-Type C-S Coupling Reaction by Sodium Aryl Sulfinates and Organoboron Compounds
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A Chan-Lam-Type C-S coupling reaction using sodium aryl sulfinates has been developed to provide diaryl thioethers in up to 92% yields in the presence of a copper catalyst and potassium sulfite. Both electron-rich and electron-poor sodium aryl sulfinates and diverse organoboron compounds were tolerated for the synthesis of aryl and heteroaryl thioethers and dithioethers. The mechanistic study suggested that potassium sulfite was involved in the deoxygenation of sulfinate through a radical process.
- Lam, Long Yin,Ma, Cong
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supporting information
p. 6164 - 6168
(2021/08/16)
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- METHOD FOR PREPARING COMPOUND AND METHOD FOR PREPARING POLYMER EMPLOYING THE SAME
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A method for preparing a compound and a method for preparing a polymer employing the same are provided. The method for preparing a compound includes reacting a compound having a structure represented by Formula (I) with a compound having a structure repre
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Paragraph 0054-0055
(2019/02/19)
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- One-pot synthesis method for substituted diphenyl sulfide
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The invention relates to a one-pot synthesis method for substituted diphenyl sulfide. The process comprises the following steps: adding thiophenol or diphenyl disulfide and derivatives thereof into asolvent, dropwise adding sulfonyl chloride for a reaction so as to obtain a substituted benzene sulfuryl chloride solution, removing a part of the solvent at a normal pressure, adding Lewis acid, thendropwise adding substituted benzene for a Friedel-Crafts reaction, and carrying out distillation or recrystallization so as to obtain the substituted diphenyl sulfide. The method provided by the invention has the advantages of high safety, simple and convenient raw material recovery, greatly-reducedpurifying difficulty, easily-available raw materials, simple unit operation, low requirements on reaction equipment, mild reaction conditions, high yield and content and applicability to industrial production; and the content of the finally obtained substituted diphenyl sulfide product generally reaches 98% or more.
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Paragraph 0079; 0080; 0081
(2019/01/08)
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- Nickel Phosphite/Phosphine-Catalyzed C-S Cross-Coupling of Aryl Chlorides and Thiols
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A method for the coupling of aryl chlorides and thiophenols using an air-stable nickel(0) catalyst is described. This thioetherification procedure can be effectively applied to a range of electronically diverse aryl/heteroaryl chlorides without more expensive metal catalysts such as palladium, iridium, or ruthenium. This investigation also illustrates both, a variety of thiol coupling partners and, in certain cases, the use of Cs2CO3.
- Jones, Kieran D.,Power, Dennis J.,Bierer, Donald,Gericke, Kersten M.,Stewart, Scott G.
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supporting information
p. 208 - 211
(2018/01/17)
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- Regioselective C-H Sulfanylation of Aryl Sulfoxides by Means of Pummerer-Type Activation
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A regioselective C-H sulfanylation of aryl sulfoxides with alkyl aryl sulfides in the presence of acid anhydride was developed, which resulted in the formation of 1,4-disulfanylarenes after dealkylation of initially formed sulfonium salts. The reaction began with Pummerer-type activation of aryl sulfoxides followed by nucleophilic attack of alkyl aryl sulfides. The nucleophilic attack occurred exclusively at the para positions, or at specific positions in case the para position was not available, under perfect control by the dominating sulfoxide directors regardless of any other substituents. The initially formed aryl sulfonium salts were isolable and usefully served as aryl halide surrogates for palladium-catalyzed arylation with sodium tetraarylborates.
- Kawashima, Hitomi,Yanagi, Tomoyuki,Wu, Chien-Chi,Nogi, Keisuke,Yorimitsu, Hideki
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supporting information
p. 4552 - 4555
(2017/09/11)
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- Iron(0) nanoparticles mediated direct conversion of aryl/heteroaryl amines to chalcogenides via in situ diazotization
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A simple procedure for the synthesis of organo-chalcogenides has been developed by the reaction of aryl/heteroaryl amines with di-aryl/heteroaryl dichalcogenides in the presence of tBuONO and Fe(0) nanoparticles. The reaction proceeds via in situ diazotization followed by chalcogenation. A series of functionalized diaryl/aryl heteroaryl/diheteroaryl/aryl-alkyl selenides, sulfides and tellurides have been obtained by this procedure. Significantly, using this procedure 2,4-dinitroaniline is converted to (2,4-dinitrophenyl)(phenyl)selane which is known as thioredoxin reductase (TR) and glutathione reductase (GR) inhibitor. The reaction goes by a radical pathway and a plausible mechanism has been suggested.
- Panja, Subir,Maity, Pintu,Kundu, Debasish,Ranu, Brindaban C.
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supporting information
p. 3441 - 3445
(2017/08/10)
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- Transition-metal-free synthesis of unsymmetrical diaryl chalcogenides from arenes and diaryl dichalcogenides
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A transition-metal-free synthetic method has been developed for the synthesis of unsymmetrical diaryl chalcogenides (S, Se, and Te) from diaryl dichalcogenides and arenes under oxidative conditions by using potassium persulfate at room temperature. Variously substituted arenes such as anisole, thioanisole, diphenyl ether, phenol, naphthol, di- and trimethoxy benzenes, xylene, mesitylene, N,N-dimethylaniline, bromine-substituted arenes, naphthalene, and diaryl dichalcogenides underwent carbon-chalcogen bond-forming reaction to give unsymmetrical diaryl chalcogenides in trifluoroacetic acid. To understand the mechanistic part of the reaction, a detailed in situ characterization of the intermediates has been carried out by 77Se NMR spectroscopy by using diphenyl diselenide as the substrate. 77Se NMR study suggests that electrophilic species ArE+ is generated by the reaction of diaryl dichalcogenide with persulfate in trifluoroacetic acid. The electrophilic attack of arylchalcogenium ion on the arene may be responsible for the formation of the aryl-chalcogen bond.
- Prasad, Ch Durga,Balkrishna, Shah Jaimin,Kumar, Amit,Bhakuni, Bhagat Singh,Shrimali, Kaustubh,Biswas, Soumava,Kumar, Sangit
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p. 1434 - 1443
(2013/03/29)
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- Chan-lam-type s-arylation of thiols with boronic acids at room temperature
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In this work, an efficient CuSO4-catalyzed S-arylation of thiols with aryl and heteroaryl boronic acids at room temperature is established. This catalytic system can tolerate a wide variety of thiols and arylboronic acids in the presence of only 5 mol % of CuSO4 as the catalyst and inexpensive 1,10-phen?H2O as the ligand. Moreover, this catalytic system used environment-friendly solvent (EtOH) and oxidant (oxygen).
- Xu, Hua-Jian,Zhao, Yong-Qiang,Feng, Teng,Feng, Yi-Si
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experimental part
p. 2878 - 2884
(2012/05/04)
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- Synthesis and properties of water-soluble asterisk molecules
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An asterisk is comprised of six semirigid arms projecting from a benzene nucleus. In the case at hand, asterisks were synthesized with one, two, or three aromatic rings (connected by sulfur atoms) in each of the six arms. A phosphomonoester at the termini of each arm solubilized the asterisks in water. The colloidal properties of these amphiphilic molecules were investigated by UV-vis and fluorescence spectroscopy, calorimetry, light scattering, surface tensiometry, and pulse-gradient spin-echo NMR. Solubility, solubilization, metal binding, and micelle "seeding" experiments were also carried out. Chain-conformation and supramolecular assembly into remarkable molecular "scrolls" were investigated by X-ray analysis and electron microscopy, respectively. One of the more interesting properties of the asterisks is that they remain monomeric in water despite having as many as 19 hydrophobic aromatic rings exposed to the water. The reasons for this behavior, and the possibility of exploiting it for constructing enzyme models free from aggregation equilibria, are discussed.
- Menger, Fredric M.,Azov, Vladimir A.
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p. 11159 - 11166
(2007/10/03)
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- Functionalized p-phenylene sulfides synthesis of new molecular wires
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Molecular wires containing p-phenylene sulfide units were synthesized. They could be used in material sciences and in supramolecular chemistry. Wires having 2 to 6 phenyl rings were functionalized at one end by an SH or SMe group, and at the other end, by an OH, OMe or OiPr groups. Formation of Ar-S bonds in the chain was achieved by Pd- or Cu-catalyzed couplings of aromatic thiols with aromatic halides. Conditions for a clean chemoselective deprotection of thiols from thiomethyl groups were developed.
- Pinchart, Alain,Dallaire, Carol,Gingras, Marc
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p. 543 - 546
(2007/10/03)
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- Synthesis of p-phenylene sulfide molecular asterisks
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'Megastars' with aromatic central cores, some of which fluoresce, were synthesized by the efficient connection of the side arms to the core by using the MacNicol reaction. Depending on the length of the side arm precursor, second-, third- (depicted), or f
- Gingras, Marc,Pinchart, Alain,Dallaire, Carol
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p. 3149 - 3151
(2007/10/03)
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- Novel efficient aromatic arylthiolation by disulfide radical cations generated by oxidation of diaryl disulfides
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The disulfide radical cation was generated by oxidation of diphenyl disulfide using H2SO4 in CF3CO2H or SbCl5 in CH2Cl2, and allowed to react with benzene, toluene, ethylbenzene, chlorobenzene, anisole and alkyl phenyl sulfides to give efficiently para-substituted diphenyl sulfides along with a small amount of the ortho-isomers. The intermediacy of the radical cation in this aromatic phenylthiolation is consistent with the evidence derived from a Hammett plot with ρ = -7.0 (using SbCl5 in CH2Cl2), from effects of oxidants, counter-anions and solvents and from electronic absorptions (540 and 650 nm). Using di-4-anisyl, di-4-tolyl and di-4-chlorophenyl disulfides instead of diphenyl disulfide, the aromatic arylthiolation similarly occurs via radical cations from their disulfides.
- Takeuchi, Hiroshi,Hiyama, Takehiro,Kamai, Noriyoshi,Oya, Hiromi
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p. 2301 - 2305
(2007/10/03)
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- Reaction of Nitric Oxide with Amines
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Reactions of nitric oxide (NO) with amines in organic solvents were studied using Hantzsch dihydropyridines and aromatic primary amines as substrates. Hantzsch dihydropyridines are readily oxidized by nitric oxide to give the corresponding pyridines in quantitative yields. The addition of oxygen accelerates the reaction rate considerably. On the other hand, aromatic primary amines give deaminated products by the reaction with nitric oxide only in the presence of oxygen in ethereal solvents or chloroform.
- Itoh, Takashi,Nagata, Kazuhiro,Matsuya, Yuji,Miyazaki, Michiko,Ohsawa, Akio
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p. 3582 - 3585
(2007/10/03)
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- Reductive deamination of aromatic amines with nitric oxide (NO)
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Aromatic amines were treated with nitric oxide in tetrahydrofuran or chloroform under argon atmosphere to afford deaminated aromatic compounds in good yields. The reaction is suggested to proceed via aryl radicals, which are supposed to be formed by reduction of aryldiazonium salts with NO.
- Itoh, Takashi,Matsuya, Yuji,Nagata, Kazuhiro,Ohsawa, Akio
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p. 4165 - 4168
(2007/10/03)
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- Novel Generation of Arylsulfenium Ion Intermediates and Efficient Aromatic Arylthiolation by the Intermediates
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Reactions of hydrazoic acid and alkyl azides with alkyl aryl sulfide in trifluoroacetic acid containing trifluoromethanesulfonic acid or H2SO4 proceeded through an S-arylaminosulfonium ion and a protonated S-arylsulfenamide, giving efficiently 4-alkylthiophenyl aryl sulfide via an arylsulfenium ion interacting with both the counter-anion and the unshared electron pair of the amine.The use of the S-arylsulfenamide instead of the azides also afforded the above product by aromatic arylthiolation in a good yield via the sulfenium ion along with its ortho-isomer, diaryl disulfide and diaryl sulfide.The formation of the sulfenium ion was demonstrated by the effect of the counter-anion, the amine, the aryl substituent of the sulfenamide and the solvent nucleophilicity.We ruled out the possibility that the arylthiolation occurs via an arylthiyl radical and an aminium radical from the sulfenamide and by direct reaction of the protonated sulfenamide with alkyl aryl sulfides.
- Takeuchi, Hiroshi,Oya, Hiromo,Yanase, Takehiro,Itou, Katsutaka,Adachi, Taki,et al.
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p. 827 - 834
(2007/10/02)
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- Novel Generation of Phenylsulfenium Ion and Aromatic Phenylthiolation. Reactions of Hydrazoic Acid, Alkyl Azides and Hydroxylamine Derivatives with Alkyl Phenyl Sulfides in the Presence of Both Trifluoromethanesulfonic Acid and Trifluoroacetic Acid
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Reactions of hydrazoic acid and alkyl azides with alkyl phenyl sulfides in the presence of both trifluoromethanesulfonic acid and trifluoroacetic acid gave 4-alkylthiophenyl phenyl sulfides in high yields via a phenylsulfenium ion.
- Takeuchi, Hiroshi,Yanase, Takehiro,Itou, Katsutaka,Oya, Hiromi,Adachi, Taki
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p. 916 - 917
(2007/10/02)
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