- Synthesis of sec-butyl disulfide by phase transfer catalysis
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Sec-Butyl disulfide was synthesized from sulfur?sodium hydroxide and sec-butyl chloride using tetrabutyl ammonium bromide as the phase transfer catalyst. The optimal experiment condition obtained by orthogonal design and the average product yield was 84.95 %. The samples synthesized under optical conditions were characterized by infrared spectrometry?gas chromatography-mass spectrometer.
- Liu, Xinqi,Wang, Jia,Zhao, Songfang,Hu, Guoqin
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- The synthesis of symmetrical disulfides by reacting organic halides with Na2S2O3·5H2O in DMSO
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A one-pot, and scalable method to prepare symmetric disulfides from their corresponding primary, secondary, allylic, and benzylic halides has been developed. In this method, a disulfide is synthesized by reacting an alkyl halide with Na2S2O3·5H2O at 60-70 °C in DMSO.
- Abbasi, Mohammad,Mohammadizadeh, Mohammad Reza,Saeedi, Narges
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supporting information
p. 89 - 92
(2016/01/12)
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- 4,4'-Azopyridine as an easily prepared and recyclable oxidant for synthesis of symmetrical disulfides from thiols or alkyl halides(tosylates)/thiourea
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Heterocyclic azo compounds, prepared from corresponding amines in one step, are used as effective oxidants for the conversion of thiols into symmetrical disulfides in high yields. Among the studied azo compounds, 4,4'-azopyridine was found to be very efficient for the odorless conversion of alkyl halides into disulfides in the presence of thiourea. An attractive feature of this azo compound is that its obtained solid side product hydrazine is easily separated by filtration and can be recycled to its azo compound for further use.
- Khalili, Dariush,Iranpoor, Nasser,Firouzabadi, Habib
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p. 544 - 555
(2015/10/19)
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- Graphene Oxide-Assisted One-Pot and Odorless Synthesis of Symmetrical Disulfides Using Primary and Secondary Alkyl Halides (Tosylates) and Thiourea as Sulfur Source Reagent
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Graphene oxide is described as a heterogeneous oxidant for the synthesis of symmetrical disulfides through the in situ generation of thiols from primary and secondary alkyl halides (tosylates) and thiourea in wet acetonitrile. A variety of alkyl halides and alkyl tosylates can be converted to corresponding disulfides in good to excellent yields. This strategy is free of foul-smelling thiols.
- Khalili, Dariush
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p. 1727 - 1734
(2015/12/12)
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- One-pot efficient synthesis of disulfides from alkyl halides and alkyl tosylates using thiourea and elemental sulfur without contamination by higher polysulfides
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An efficient and odorless synthesis of disulfides from alkyl halides using thiourea and elemental sulfur in the presence of sodium carbonate in wet polyethylene glycol (PEG 200) at 40 C without contamination by higher polysulfides has been developed. This procedure was then extended to preparation of disulfides from alkyl tosylates at 70 C.
- Abbasi, Mohammad,Mohammadizadeh, Mohammad Reza,Taghavi, Zeinab Khatoon
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p. 201 - 205
(2013/07/26)
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- Efficient and convenient oxidation of thiols to symmetrical disulfide with silica-PCl5/NaNO2 in water
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A very simple, environmentally benign, cost-effective, and efficient synthesis of disulfides from thiols using silica-PCl5/NaNO2 in aqueous medium has been described. The reaction was found to occur rapidly under mild conditions, and disulfides were obtained easily through a simple workup.
- Pathak, Uma,Pandey, Lokesh Kumar,Mathur, Sweta
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experimental part
p. 2923 - 2927
(2009/12/03)
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- H14[NaP5W30O110] as a heterogeneous recyclable catalyst for the air oxidation of thiols under solvent free conditions
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The catalytic oxidation of thiols to the corresponding disulfides using Preyssler's catalyst H14[NaP5W30O 110] has been studied. These highly selective oxidations gave good yields of the target disulfides.
- Hekmatshoar, Rahim,Sajadi, Sodeh,Heravi, Majid M.,Bamoharram, Fatemeh F.
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p. 2223 - 2228
(2008/02/11)
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- Dinitrogen tetroxide impregnated charcoal (N2O 4/Charcoal): Selective oxidation of thiols to disulfides or thiosulfonates
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Selective oxidation of thiols to disulfides (RSSR) was performed by using catalytic amounts of dinitrogen tetroxide/charcoal in chloroform at r.t. while the reaction of thiols with four molar equivalents of the reagent in dichloromethane afforded thiosulfonates (RSO2SR) with excellent yields. Copyright Taylor & Francis Group, LLC.
- Iranpoor, Nasser,Firouzabadi, Habib,Pourali, Ali Reza
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p. 473 - 479
(2007/10/03)
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- Oxidation/reduction interconversion of thiols and disulfides using hydrogen and oxygen catalyzed by a rhodium complex
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RhH(PPh3)4 catalyzes reduction of disulfides to thiols by hydrogen and RhH(PPh3)4/1,4- bis(diphenylphosphino)butane (dppb) catalyzes oxidation of thiols to disulfides by oxygen.
- Arisawa, Mieko,Sugata, Chiyoshi,Yamaguchi, Masahiko
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p. 6097 - 6099
(2007/10/03)
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- Method for preparing aromatic diphenyl thioethers
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The invention concerns a method for preparing aromatic diphenyl thioethers. More particularly the invention concerns the preparation of 4-chloro-4′-thiomethyldiphenylether. The inventive method for preparing an aromatic diphenyl thioether is characterised in that it consists in reacting in an aqueous medium a diazonium salt of an aromatic diphenyl compound with a disulphide sulphur compound, in the presence of an efficient amount of a coupling catalyst.
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- Oxidation of thiols to disulfides with molecular bromine on hydrated silica gel support
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Results of oxidation of thiols to disulfides with molecular bromine on silica gel solid support are reported. The procedure utilizes organic media and does not require a base to neutralize HBr by-products to suppress acid promoted side reactions. Utilization of silica gel support simplifies work up and product isolation.
- Ali, Mohammed Hashmat,McDermott, Mario
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p. 6271 - 6273
(2007/10/03)
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- Dinitrogen tetroxide supported on polyvinylpyrrolidone (PVP-N2O4): A new nitrosating and coupling agent for thiols and a selective oxidant for sulfides and disulfides
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Gaseous N2O4 was immobilized on polyvinylpyrrolidone to give a stable polymeric reagent. Thiols were converted to S-nitrosothiols (thionitrites) using this new nitrosating agent in n-hexane or CHCl3 at 10°C. With this reagent, thiols were also converted into their corresponding disulfides. Selective oxidation of sulfides to sulfoxides and disulfides to thiosulfonates can also be achieved by this reagent at room temperature. By using an excess of the reagent, the selective one-pot synthesis of thiosulfonates from thiols at room temperature was also performed.
- Iranpoor, Nasser,Firouzabadi, Habib,Pourali, Ali-Reza
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p. 5179 - 5184
(2007/10/03)
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- Alkyl- and Arylthiodediazoniations of Dry Arenediazonium o-Benzenedisulfonimides. Efficient and Safe Modifications of the Stadler and Ziegler Reactions to Prepare Alkyl Aryl and Diaryl Sulfides
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The reaction between dry arenediazonium o-benzenedisulfonimides 1 and sodium thiolates in anhydrous methanol represents an efficient and safe procedure, of general validity, for the preparation of unfunctionalized or variously functionalized alkyl aryl and diaryl sulfides. As a rule, the reaction temperature was maintained at 0-5°C for the alkylthiodediazoniations and at room temperature (20-25°C) for the arylthiodediazoniations. The sulfide yields are generally high; of the 63 considered examples, 43 gave yields greater than 80% and 13 were between 70% and 80%. Lower yields were obtained only when sterically hindered diazonium salts or thiols were used. A good amount of the o-benzenedisulfonimide (8) was always recovered from the reactions and could be reused to prepare salts 1. The copious experimental data collected in homogeneous conditions have offered several starting points for the study of the mechanism of these reactions.
- Barbero, Margherita,Degani, Iacopo,Diulgheroff, Nicola,Dughera, Stefano,Fochi, Rita,Migliaccio, Mara
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p. 5600 - 5608
(2007/10/03)
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- Oxidation of thiols to bisulfides by elemental sulfur without contamination by higher polysulfides
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Dialkyl disulfides were prepared in near quantitative yield by oxidation of alkanethiols with elemental sulfur using NaOH and ethoxylated alcohols as catalysts. Tergitol 15-S-7 was one of several ethoxylated alcohols which was used. Contamination by trisulfides was essentially eliminated in the disulfide products. The ratios of disulfide to trisulfide ranged from 100/0 to 99.6/0.4 for reactions with primary and secondary alkanethiols (100% excess) such as 1-propanethiol, 1-octanethiol, 2-propanethiol, and 2-butanethiol. The process did not work for tertiary alkanethiols such as 2-methyl-2-propanethiol where the trisulfide was greatly favored.
- Shaw, James E.,McAfee, Marilyn G.
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p. 125 - 131
(2007/10/03)
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- Preparation of dithioselenides via a selenium transfer reagent
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The addition of two moles of thiol to a unique selenium-transfer reagent, bis azole selenide 4, results in very good isolated yields of dithioselenides (RS-Se-SR).
- Ryan, M. Dominic,Harpp, David N.
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p. 8829 - 8832
(2007/10/03)
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- Use of a sacriflcial-sulfur electrode in electroorganic chemistry. V. Formation of the sequence CSSSC from S and thiols or thiolates
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At a working potential of about +2.0 V (vs SCE) the carbon-sulfur electrode is a source of the electrogenerated cation S2+. In organic media, this electrophile reacts with thiols (or thiolates) to give a mixture of polysulfides of which the trisulfide is the main product. The reaction between electrogenerated Sy2- and alkyl halides is less selective. Elsevier,.
- Do, Quang Tho,Elothmani, Driss,Simonet, Jacques,Guillanton, Georges Le
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p. 273 - 281
(2007/10/03)
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- Formation and scission of the sulfur-sulfur bond: a new approach to reactions between sulfur/polysulfide ions and thiolate ions/disulfides in N,N-dimethylacetamide
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The reactivity of sulfur towaards a series of thiolate ions RS- has been studied by spectroelectrochemistry in N,N-dimethylacetamide.Apparently, sulfur reacts in two parallel ways: (i) oxidation of RS- leading to RS2R and S3 anion radical ions; (ii) preponderant S-nucleophilic process yielding stable RSx- ions (x = 2-5).RSx- species, whose spectrophotometric characteristics have been determined, are successively obtained in the course of sulfur addition with R = alkyl, whereas equilibria between arylpolysulfide ions were observed.At the junction of these two parallel pathways, the slow keyequilibrium 2RS4- RS2R + 2S3 radical anion has been investigated by addition of RS2RR = 1-8 to S3 radical anion solutions.In fact, our study is consistent with a first, a monoelectronic transfer between RS- (or RS2-) ions and the very reactive S2 molecules in equilibrium with S8.The fact and competing couplings of the radicals RS (or RS2 radical), S2 radical anion (or S3 radical anion) agree with the simultaneous formation of RS2R, RSx- and polysulfide ions.More generally, the S2/S2 radical anion redox system is believed to be involved in thiophilic reactions of a number of anions such as RS- towards sulfur rather than the initial opening of the cyclic S8 form.
- Bosser, Gerard,Anouti, Meriem,Paris, Jacky
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p. 1993 - 2000
(2007/10/03)
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- The Regioselective Reaction of Atomic Hydrogen with Unsymmetric Disulfides and Sulfides
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Unsymmetrical disulfides undergo solution phase reduction with atomic hydrogen regioselectively by displacement at the least hindered sulfur atom.The cleavage of the sulfur-sulfur bond forms mixtures of two thiol and two thiyl radicals.At the temperature at which the reactions are carried out, the thiyl radicals form symmetric disulfides by thiyl-thiyl radical coupling and not by thiyl radical displacement on the starting material.The reaction of atomic hydrogen with an unsymmetric sulfide is a cleavage that favors the formation of the most stable radical.The reaction of phenyl cyclohexyl sulfide produces benzene, cyclohexane, cyclohexyl thiol, and thiophenol.Benzene and cyclohexyl thiol produced from the cleavage of the phenyl-sulfur bond are proposed to arise from the α-scission of an intermediate formed by ipso-addition of atomic hydrogen to the benzene ring.
- Tanner, Dennis D.,Zhang, Liying,Vigneswaran, Markandu,Kandanarachchi, Pramod
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p. 4481 - 4487
(2007/10/02)
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- A New Group of Compounds Derived from Nereistoxin - Synthesis of Bis-dimethylamino-tris-disulfanes
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The reaction of organo-thiosulfates, BUNTE-salts, with mercaptans is a convenient synthesis of disulfanes.Similarly bis-BUNTE-salt 7 and tert. butyl mercaptan give bis-disulfane 5c.By treating 7 with several aliphatic mercaptans we found the formation of the tris-disulfanes 8a-d in preparative amounts in addition to the bis-disulfanes 5a-d expected.This reaction was investigated.The preparation of the compounds 8 is described and a proposal is given for a mechanism of the formation of 8 as a thiol-disulfide-interchange.
- Muehlstaedt, M.,Heinicke, J.,Schubert H.
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p. 841 - 847
(2007/10/02)
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- Electrocatalytic Oxidation of Thiols on a TEMPO Modified Electrode
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Monothiols were oxidized efficiently and quantitatively to disulfides on graphite felt electrode coated with 4-amino-2,2,6,6-tetramethylpiperidinyl-1-oxyl (4-amino-TEMPO).The 4-amino-TEMPO was immobilized through an amide linkage with poly(acrylic acid).The poly(acrylic acid) was crosslinked with 1,6-diaminohexane, and the residual carboxyl groups were methylated with diazomethane.The electrode was stable and could be used repeatedly.
- Kashiwagi, Yoshitomo,Ohsawa, Akio,Osa, Tetsuo,Ma, Zhenkun,Bobbitt, James M.
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p. 581 - 584
(2007/10/02)
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- Electrochemical Oxidation of Thiols to Disulfides
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Disulfides can be easily prepared by electrochemical oxidation of the corresponding thiols in methanol/sodium methoxide solution under constant current conditions.
- Leite, Sergio L.S.,Pardini, Vera L.,Viertler, Hans
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p. 393 - 397
(2007/10/02)
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- Efficient, high yield oxidation of thiols and selenols to disulphides and diselenides
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Thiols and selenols are smoothly oxidised in high yield to disulphides and diselenides by sodium perborate at room temperature.
- McKillop,Koyuncu,Krief,Dumont,Renier,Trabelsi
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p. 5007 - 5010
(2007/10/02)
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- KINETICS AND MECHANISM OF THE OXIDATION OF 1-BUTANETHIOL AND 2-BUTANETHIOL BY HEXACYANOFERRATE (III) ION IN METHANOL-WATER MEDIUM
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The kinetics of the oxidation of 1-butanethiol and 2-butanethiol by hexacyanoferrate (III) ion in methanol-water medium and in presence of hydroxyl ions have been studied.The reactions show a first order dependence on hexacyanoferrate (III) ion and a zero order in thiol when great excess is used (15-60 times).In the oxidation of 1-butanethiol (1-BT), the order in hydroxyl ions shows a transition from zero towards unity whereas in the case of 2-BT, the first order rate constant increases linearly with increasing hydroxyl ion concentration.The reaction follows second order kinetics at low concentrations of thiol (ca. -3 M), and the second order rate constant decreases with increasing thiol concentration.The kinetic data indicate that the accumulation of hexacyanoferrate (II) ions is responsible for the change of kinetics.This possibility has been further explored, and the results are presented in Part II of the present communication.The rate increases with increasing ionic strength, and dielectric constant of the medium.Activation parameters have been evaluated and discussed on the basis of kinetic and steric effects.
- Kalla, K. G.,Mishra, K. K.
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p. 183 - 194
(2007/10/02)
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- OXIDATION OF THIOLS TO THEIR DISULFIDES WITH BIS CHROMATE 2CrO4 AND PYRIDINIUM CHLOROCHROMATE
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Oxidation of thiophenols, benzyl thiol, and alkyl thiols with bis chromate and pyridinium chlorochromate are investigated.Pyridinium chlorochromate is quite ineffective for the oxidative dimerization of alkyl thiols.
- Firouzabadi, H.,Iranpoor, N.,Parham, H.,Sardarian, A.,Toofan, J.
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p. 717 - 724
(2007/10/02)
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- VOLATILE POLYSULPHIDES OF ASAFOETIDA
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By means of steam distillation, adsorption chromatography and GC/MS analysis, seven sulphur components (di-, tri- and tetrasulphides) have been characterized in addition to those previously reported from Ferula asafoetida of Afghan origin.The identity of some of the components has been confirmed by synthesis and comparison of GC retentions.The quantitative composition of the constituents in the volatile oil has also been determined.Key Word Index - Ferula asafoetida; Umbelliferae; volatiles; oleoresin; 2-butyl methyl disulphide; 2-butyl methyltrisulphide; and di-2-butyl tetrasulphide.
- Rajanikanth, B.,Ravindranath, B.,Shankaranarayana, M. L.
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p. 899 - 900
(2007/10/02)
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- Peculiar Aspects of the Anodic Oxidation of Vinylic Sulfides
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In the anodic oxidation of vinylic sulfides on platinum in acetonitrile, a non-classical sulfonium ion explains satisfactorily the transfer of the thioether group leading to an aldehyde in the presence of water, or its acetal in the presence of methanol.Some other reactions depend on the structure of the substrate, particularly the dimerization into anodically inactive forms likely to decompose during the work-up, to lead in some cases to masked ketenes having the structure of a gem-disulfide.
- Guillanton, Georges Le,Simonet, Jacques
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p. 437 - 444
(2007/10/02)
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- THE FACILE OXIDATION OF THIOLS TO DISULFIDES WITH BIS(2,2'-BIPYRIDYL)COPPER(II) PERMANGANATE
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The title compound is used in the oxidation of several thiols to produce their corresponding disulfides inexcellent yields in methylene chloride at room temperature.
- Firouzabadi, H.,Naderi, M.,Sardarian, A.,Vessal, B.
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p. 611 - 616
(2007/10/02)
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- KINETICS AND MECHANISM OF THE OXIDATION OF 2-BUTANETHIOL BY 2,6-DICHLOROPHENOLINDOPHENOL IN ACETONE-WATER MEDIUM
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The oxidation kinetics of 2-butanethiol by 2,6-dichlorophenolindophenol in acetone-water medium (40 percent v/v) and in presence of phosphate buffer are described.The reaction shows zero order in 2-butanethion and second order with respect to 2,6-dichlorophenolindophenol.The rate increases with increase in +>.The relationship between the two is not, however, simple.Variation in ionic strength and the addition of reaction products have no effect on rate.There is a linear relationship between 'log k2' and the inverse of the dielectric constant with a negative slope.Activation parameters have been determined and a plausible mechanism is proposed.
- Pandey, N. K.,Mishra, K. K.
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p. 179 - 182
(2007/10/02)
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- Chemical Conversions using Sheet Silicates: Novel Intermolecular Eliminations of Hydrogen Sulphide from Thiols
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Aliphatic primary and secondary thiols react in the interlamellar layers of ion-exchanged montmorillonite catalysts to produce dialkyl sulphides via intermolecular elimination of hydrogen sulphide; similar processes result in the production of diphenyl sulphide from benzenethiol and poly(phenylenemethylene) from α-toluenethiol.
- Ballantine, James A.,Galvin, Robert P.,O'Neil, Robert M.,Purnell, Howard,Rayanakorn, Mongkon,Thomas, John M.
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p. 695 - 696
(2007/10/02)
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- ACTION OF ELEMENTARY SULFUR ONTO CARBANIONS: A NEW ROUTE TO DIALKYLPOLYSULFIDES
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The reaction of sec-Butyllithium with elemental sulfur leads to the formation of dialkylpolysulfides.
- Boscato, J. F.,Catala, J. M.,Franta, E.,Brossas, J.
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p. 1519 - 1520
(2007/10/02)
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- Rate Constants and Equilibrium Constants for Thiol-Disulphide Interchange Reactions Involving Oxidized Glutathione
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The rate of reduction of oxidized glutathione (GSSG) to glutathione (GSH) by thiolate (RS-) follows a Broensted relation in pKas of the conjugate thiols (RSH): βnuc ca. 0.5.This value is similar to that for reduction of Ellman's reagent: βnuc ca. 0.4 - 0.5.Analysis of a number of rate and equilibrium data, taken both from this work and from the literature, indicates that rate constants, k, for a range of thiolate-disulphide interchange reactions are correlated well by equations of the form log k = C + βnucpKanuc + βcpKac + βlgpKalg ( nuc = nucleophile, c = central, and lg = leaving group sulfur): eq 36 - 38 give representative values of the Broensted coefficients.The values of these Bronsted coefficients are not sharply defined by the available experimental data, although eq 36 - 38 provide useful kinetic models for rates of thiolate-disulfide interchange reactions.The uncertainty in these parameters is such that their detailed mechanistic interpretation is not worthwhile, but their qualitative interpretation - that all three sulphur atoms experience a significant effective negative charge in the transition state, but that the charge is concentrated on the terminal sulfurs - is justified.Equilibrium constants for reduction of GSSG using α,ω-dithiols have been measured.The reducing potential of the dithiol is strongly influenced by the size of the cyclic disulfide formed on its oxidation: the most strongly reducing dithiols are those which can form six-membered cyclic disulfides.Separate equilibrium constants for thiolate anion-disulphide interchange (KS-) and for thiol-disufide interchange (KSH) have been estimated from literature data: KS- is roughly proportional to 2ΔpKa is the difference between the pKas of the two thiols involved in the interchange.The contributions of thiol pKa values to the observed equilibrium constants for reduction of GSSG with α,ω-dithiols appear to be much smaller than those ascribable to the influence of structure on intramolecular ring formation.These equilibrium and rate constants are helpful in choosing dithiols for use as antioxidants in solutions containing proteines: dithiothreitol (DTT), 1,3-dimercapto-2-propanol (DMP), and 2-mercaptoethanol have especially useful properties.
- Szajewski, Richard P.,Whitesides, George M.
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p. 2011 - 2026
(2007/10/02)
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