- SYNTHESIS OF MONOFUNCTIONAL THIURAM ACCELERATOR
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The present invention provides a route for synthesizing monofunctional thiuram compounds that is safe, environmentally friendly, and cost effective. This method specifically involves synthesizing a monofunctional thiuram by (1) reacting a tetraorganylthiuram disulfide with an organyl mercaptan to produce the monofunctional thiuram and a dithiocarbamate metal salt or a dithiocarbamate metalloid salt under basic conditions, (2) separating the monofunctional thiuram in an organic phase from the dithiocarbamate metal salt or the dithiocarbamate metalloid salt in an aqueous phase, and (3) recovering the monofunctional thiuram from the aqueous phase. The monofunctional thiuram compounds made in accordance with this invention are of particular value as accelerators for use in the vulcanization of rubber. The use of these monofunctional thiuram compounds as accelerators provides good cure rates and as well as good scorch safety.
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Paragraph 0020
(2021/07/02)
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- Electrochemical Synthesis of Organic Polysulfides from Disulfides by Sulfur Insertion from S8 and an Unexpected Solvent Effect on the Product Distribution
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An electrochemical synthesis of organic polysulfides through sulfur insertion from elemental sulfur to disulfides or thiols is introduced. The highly economic, low-sensitive and low-priced reaction gives a mixture of polysulfides, whose distribution can be influenced by the addition of different amounts of carbon disulfide as co-solvent. To describe the variable distribution function of the polysulfides, a novel parameter, the “absorbance average sulfur amount in polysulfides” (SAP) was introduced and defined on the basis of the “number average molar mass” used in polymer chemistry. Various organic polysulfides were synthesized with variable volume fractions of carbon disulfide, and the yield of each polysulfide was determined by quantitative 13C NMR. Moreover, by using two symmetrical disulfides or a disulfide and a thiol as starting materials, a mixture of symmetrical and asymmetrical polysulfides could be obtained.
- F?hrmann, Jan,Hilt, Gerhard
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p. 11141 - 11149
(2021/06/09)
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- Unsymmetrical Disulfides Synthesis via Sulfenium Ion
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An umpolung approach for the synthesis of unsymmetrical disulfides via sulfenium ion is reported. In situ generated electrophilic sulfenium ion from electron-rich thiols reacted with second thiols to yield unsymmetrical disulfides. Using an iodine catalyst and 4-dimethylaminopyridine (DMAP)/water as promoter, the target syntheses were achieved in one pot under aerobic condition.
- Parida, Amarchand,Choudhuri, Khokan,Mal, Prasenjit
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supporting information
p. 2579 - 2583
(2019/07/15)
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- A convenient method for the preparation of functionalized N-acylsulfenamides from primary amides
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We have developed a convenient method for the synthesis of functionalized N-acylsulfenamides under mild conditions and in moderate to good yields. The designed method is based on the reaction of (5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl)-disulfanyl derivatives with nitrogen nucleophiles generated from primary amides or imides and sodium hydride. The developed method allows for the preparation of N-acylsulfenamides bearing additional hydroxyl, carboxyl, or amino functionalities.
- Musiejuk, Mateusz,Witt, Dariusz
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supporting information
p. 305 - 310
(2016/02/18)
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- DDQ-mediated synthesis of functionalized unsymmetrical disulfanes
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We developed a simple and efficient method for the synthesis of functionalized unsymmetrical disulfanes under mild conditions in good yields. The designed method is based on the reaction of bis(5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl)disulfane with thiols in the presence of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ). The developed method allows the preparation of unsymmetrical disulfanes bearing additional hydroxy, carboxy, or amino functionalities.
- Musiejuk, Mateusz,Klucznik, Tomasz,Rachon, Janusz,Witt, Dariusz
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p. 31347 - 31351
(2015/04/22)
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- A novel one pot synthesis of benzyl sulfides: Samarium-induced, benzyl bromide mediated reduction of alkyl thiocyanates and diaryl disulfides in methanol
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A convenient synthesis of benzyl Sulfides by the treatment of alkyl thiocyanates or diaryl disulfides with metallic samarium and benzyl bromide in methanol has been developed.
- Zhan, Zhuang-Ping,Lang, Kai
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p. 443 - 444
(2007/10/03)
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- Water effects on SmI2 reductions: A novel method for the synthesis of alkyl thiols by SmI2-promoted reductions of sodium alkyl thiosulfates and alkyl thiocyanates
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Water as a cosolvent has significant improving effect on the reductivity of SmI2 in the reduction of sodium alkyl thiosulfates and alkyl thiocyanates. A new method for synthesis of alkyl thiols by SmI 2/THF/H2O system has been developed.
- Zhan, Zhuang-Ping,Lang, Kai,Liu, Feng,Hu, Li-Ming
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p. 3203 - 3208
(2007/10/03)
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- Preparation of disulfides by the oxidation of thiols using trichloroisocyanuric acid
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Thiols are readily oxidized to disulfides by a solution of pyridine, water, benzoic acid and trichloroisocyanuric acid in acetonitrile and methylene chloride.
- Zhong,Guo
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p. 1825 - 1828
(2007/10/03)
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- 1-nitro-2-thio(sulfonyl)alkenes in reactions with thiols
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Reactions of 1-nitro-2-sulfonylalkenes with arenethiolates result in replacement of the sulfonyl group; the reactions with alkanethiolates are accompanied by subsequent addition of the reagent at the double bond to afford thioacetals. Less reactive α-nitro-β-R-thiostyrenes with thiolates at reduced temperature form addition products which are converted into the corresponding substitution products on storage at room temperature, in keeping with the addition-elimination mechanism of nucleophilic vinyl substitution. Nitro(arylthio)- and nitro(heterylthio)alkenes react with alkanethiolates at room temperature, resulting in replacement of the arylthio (heterylthio) group by alkylthio.
- Kuz'mina,Lipina,Kropotova,Berkova,Pavlova
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p. 1259 - 1265
(2007/10/03)
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- Oxidation by Chemical Manganese Dioxide. Part 2.1 Simple and High-yielding Synthesis of Symmetrical Disulfides via the Oxidative Coupling of Thiols
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Aromatic, aliphatic, and alicyclic thiols readily underwent oxidative coupling with chemical manganese dioxide in hexane to afford the corresponding disulfides in essentially quantitative yields under relatively mild conditions.
- Hirano, Masao,Yakabe, Sigetaka,Chikamori, Hideki,Clark, James H.,Morimoto, Takashi
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p. 310 - 311
(2007/10/03)
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- 2-benzoylbenzoic acid: A photolabile mask for alcohols and thiols
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Photolysis of 2-benzoylbenzoate esters of primary and secondary alcohols 1 in the presence of a hydrogen donor (2-isopropanol) or an electron donor (primary amines) produces the corresponding alcohol in high yield. The fate of the benzoate is dependent on the conditions used for the photoreaction. In 2-propanol, the ketyl radical that derives from photoreduction dimerizes, to afford the benzpinacol product 3,3"-diphenylbiphthalidyl, 5. In the presence of amines the product is 3-phenylphthalide, 6, a benzhydrol derivative which is the result of simple reduction of the ketone followed by lactonization. While the photoproduct of the benzoate - 2-propanol reaction results from anticipated free radical chemistry, the amine-promoted reaction appears to result from a second, "dark", electron transfer process. We conclude that 2-benzoylbenzoic acid is an effective photolabile protecting group for primary and secondary alcohols, and preliminary studies indicate that thiols can be protected in an analogous way. Studies on the effect of benzophenone substituents and reaction solvent on the benzhydrol:benzpinacol product ratio provide mechanistic insight into the process.
- Jones, Paul B.,Pollastri, Michael P.,Porter, Ned A.
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p. 9455 - 9461
(2007/10/03)
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- Kinetics and Mechanism of the Oxidation of 1-Dodecanethiol by 2.6-Dichlorophenolindophenol (a Coenzyme Q Model) in Aqueous-Acetone Medium
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The oxidation kinetics of 1-dodecanethiol by 2.6-dichlorophenolindophenol in aqueous acetone medium and in presence of hydroxyl ions have been studied colorimetrically.The reaction follows a first order kinetics in each principal reactant.The increase in hydroxyl ion concentration decreases the rate in a complex manner.The addition of reaction products does not affect the rate but a slight variation is noticed on increasing the ionic strenght of the system.The rate increases on increasing the dielectric constant of the medium.The reaction was studied at differenttemperatures and activation parameters were evaluated.A suitable mechanism consistent with the kinetic data has been proposed which leads to the following rate expression: .
- Kashyap, M.,Mishra, K. K.
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p. 331 - 339
(2007/10/02)
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