- Facile preparation of bis(thiocarbonyl)disulfides via elimination
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A robust facile synthetic preparation of bis(thiocarbonyl)disulfides is presented. The route follows an elimination mechanism rather than the more common oxidation. Addition of p-tosyl chloride to a thiocarbonyl thiolate results in the elimination of the chloride by the trithiocarbonate anion and subsequent elimination of the tosyl leaving group (by a second thiocarbonyl thiolate). The side products of the reaction are bis(4-methylphenyl)disulfone and tosylate salts/acids.
- Weber, Wolfgang G.,McLeary, James B.,Sanderson, Ron D.
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p. 4771 - 4774
(2007/10/03)
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- Searching for more effective agents and conditions for the RAFT polymerization of MMA: Influence of dithioester substituents, solvent, and temperature
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A series of tertiary ditbiobenzoates differently substituted on the pbenyl group (Z) were synthesized in order to investigate the RAFT-mediated polymerization of MMA. The chain-transfer agent 2-cyanoprop-2-yl dithiobenzoate, although an excellent RAFT agent for polymerization of MMA, does not yield a very narrow polydispened polymer at low conversion. The introduction of electron-withdrawing substituents on the dithiobenzoate aromatic ring improves the activity of the chain-transfer agent narrowing the molecular weight distribution, especially in the first 2 h of the process; conversely, electron-donating substituents deteriorate the performance of the process in the early stages. Substituents on the dithiobenzoate that, for reasons of steric hindrance reduce the conjugation of the phenyl with the C-S double bond of the dithiogroup, diminish the effectiveness of the chain-transfer agent. The nature of the leaving group (R) also has a strong influence on the process: the substitution of 2-cyanoprop-2-yl with the bulkier 2-cyano-4-methylpent-2-yl as leaving group improves remarkably the MMA polymerization, especially in the early stages. The solvent effect on MMA RAFT polymerization using benzene, acetonitrile, and DMF was also investigated. The lower propagation rate constant of MMA in benzene gives rise to reduced rates of polymerization but narrower polydispersities of the polymer, especially at low conversions. The RAFT polymerizations of MMA were carried out at 60 and 90°C to assess the temperature dependence of the process. The higher temperature increases both the rate of polymerization and the transfer constant of the RAFT agent, resulting in lower polydispersities at a given conversion. Ab initio calculations confirmed the observed experimental results.
- Benaglia, Massimo,Rizzardo, Ezio,Alberti, Angelo,Guerra, Maurizio
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p. 3129 - 3140
(2007/10/03)
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- Preparation and Some Reactions of Thioacyl Diphenylthiophosphinoyl and Thioacyl Diphenylphosphino Sulfides
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The reaction of sodium or caesium dithiocarboxylates with diphenylthiophosphinic and diphenylselenophosphinic chlorides gives purple thioacyl diphenylthiophosphinoyl 5 and dark green thioacyl diphenylselenophosphinoyl sulfides 6, which are useful thioacylating reagents under mild reaction conditions.Thioacyl diphenylphosphino sulfides 22, which can be obtained by the similar method using diphenylphosphinous chlorides, react with methanol to yield the corresponding methyl dithiocarboxylates 15, while the reactions of 22 with N-chlorosuccinimide lead to hitherto unknown N-(thioacetylthio)succinimides 28.
- Kato, Shinzi,Goto, Masahisa,Hattori, Rikizoh,Nishiwaki, Koh-ichi,Mizuta, Masateru,Ishida, Masaru
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p. 1668 - 1683
(2007/10/02)
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- Raney Nickel Desulphuration of Some Dithioacid Derivatives
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Raney Nickel desulphuration of some bisthioaroyl disulphides (I), and lead salts (II) and esters (III) of dithioacids with W-2A, W-2B and W-2C catalysts has been investigated.In some cases dimorphic products are obtained.
- Latif, K. A.,Ali, M. Umar
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p. 471 - 473
(2007/10/02)
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- Preparation and Some Reactions of Phenylmercury Thio- and Dithiocarboxylates
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It has been found that the reaction of diphenylmercury with an equimolar amount of thio- or dithio acids gave the corresponding phenylmercury thio- (1) or dithiocarboxylates (2), quantitatively, which further react with thio- or dithio acids to give mercury bis(thio-) (3) or bis(dithiocarboxylates) (4).The phenylmercury dithio salts (2) were found to be the very useful thioacylating agents for primary and secondary amines.The reaction of mercury bis(thiocarboxylates) (3) with dithiocarboxylic acids gave the unsymmetrical thio- and dithiocarboxylic acid mercury salts (5) in good yield. - Keywords: Phenylmercury Thiocarboxylates
- Kato, Shinzi,Hattori, Eiji,Sato, Hiroyuki,Mizuta, Masateru,Ishida, Masaru
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p. 783 - 790
(2007/10/02)
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