- Thermal rearrangement of terf-butylsulfinamide
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tert-Butylsulfinamides are unstable above room temperature, and in chlorinated solvents they undergo rearrangement to form the more stable N-(tert-butylthio)-tert-butylsulfonamide.
- Arava, Veera Reddy,Gorentla, Laxminarasimhulu,Dubey, Pramod Kumar
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- A rapid and efficient synthesis of symmetrical disulfides under microwave irradiation conditions
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A rapid and general method for the synthesis of symmetrical disulfides involves reaction of sulfur with sodium hydroxide under PTC-microwave irradiation condition to give sodium disulfide, which reacts with alkyl halides to afford the disulfides in good to excellent isolated yields.
- Wang, Jin-Xian,Gao, Lijuan,Huang, Danfeng
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- The Titanium Dioxide Sensitised Photo-Oxidation of Sulphides
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Titanium dioxide has been shown to photosensitise the oxidation of sulphides to give sulphoxides and sulphones.Evidence is presented against the involvement of singlet oxygen and in favour of the sulphide radical cations as being intermediates.
- Davidson, R. Stephen,Pratt, Julie E.
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- Reactivity of Nucleophiles toward and the Site of Nucleophilic Attack on Bis(alkylthio) Selenides
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Bis(alkylthio)selenides, RSSeSR (1), a class of compounds that occupy a key role as intermediates in the incorporation of inorganic selenium into biological systems, react quite readily with nucleophilic reagents.In principle, such reactions could take place at either sulfur (eq 3a) or at selenium (eq 3b).In the present work the reaction of a series of 1 having R groups of varying steric dimensions (n-Bu, i-Pr, t-Bu) with a group of common nucleophiles (thiolate, cyanide, and sulfite ions, phenyllithium, piperidine) has been examined.The results show that when R = t-Bu, reaction with the nucleophile at selenium occurs considerably faster than reaction at sulfur, but that when R is an n-alkyl group (n-Bu), reaction at sulfur is considerably faster than reaction at selenium.With R = i-Pr, the rates of reaction at the two sites are comparable.For reaction at sulfur, the retardation in rate accompanying a change in R from n-Bu to i-Pr to t-Bu parallels closely the decrease in rate with the same change in R that has been observed in other nucleophilic substitution at dicoordinate sulfur.As might be expected, an increase in steric dimensions of R has a considerably smaller effect on the rate of mechanism at selenium.Comparison of the rate of reaction of n-BuS- with n-BuSSeSBu-n and n-BuSSBu-n shows that bis(n-alkylthio) selenides can be expected generally to be more than several orders of magnitude more reactive toward nucleophiles than the corresponding disulfide.
- Kice, John L.,Slebocka-Tilk, Henryka
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- Synthesis and decomposition of some dialkyl oxide derivatives of organotrisulfides
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The isolation or detection of sulfenic sulfonic thioanhydrides 1 (e.g., 6), sulfenyl vic-disulfoxides 4 (e.g., 9, 14), and sulfinic thioanhydrides 5 (e.g., 20) has been carried out by oxidative procedures at various temperatures. The decomposition of these compounds has been investigated and is shown to be consistent with the mechanism proposed for the decomposition of trisulfide monoxides.
- Derbesy, Gerard,Harpp, David N.
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- Metal-free air oxidation of thiols in recyclable ionic liquid: A simple and efficient method for the synthesis of disulfides
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An efficient procedure for the oxidative coupling of alkyl, aryl and heteroaryl thiols with atmospheric oxygen is reported. The methodology utilizes BMIM-BF4 as a recyclable solvent and does not require support materials or metal salts. Symmetric disulfides are obtained in excellent yields.
- Singh, Devender,Galetto, Fabio Z.,Soares, Letiere C.,Rodrigues, Oscar E. Dorneles,Braga, Antonio Luiz
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- The rapid and efficient synthesis of disulfides from alkyl and acyl halides
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Various symmetrical dialkyl and diacyl disulfides are prepared easily in high yields from the corresponding alkyl and acyl halides under mild and nonaqueous conditions using N,N'-dibutyl-N,N,N',N'-tetramethyl- ethylenediammonium tetrahydroborate (BTMETB) or N,N'-dibenzyl-N,N,N',N'- tetramethylethylenediammonium tetrahydroborate (BZTMETB) and elemental sulfur. The quaternary diammonium borohydrides were easily prepared by treatment of the corresponding quaternary diammonium chloride or bromide with alkaline solution of sodium borohydride at room temperature.
- Tajbakhsh, Mahmood,Lakouraj, Moslem M.,Mahalli, Majid S.
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- Oxidation of thiols to disulfides with monochloro poly(styrenehydantoin) beads
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Various thiols were converted to symmetrical disulfides. This facile and reproducible method uses water as a solvent, and monochloro poly(styrenehydantoin) beads as an oxidizing agent.
- Akdag, Akin,Webb, Thomas,Worley
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- CATALYTIC OXIDATION OF THIOLS BY COENZYME PQQ
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Oxidation of thiols by coenzyme PQQ as a new enzymatic oxidation-reduction model was found to proceed catalytically under aerobic conditions to give corresponding disulfides.
- Itoh, Shinobu,Kato, Nobuyuki,Ohshiro, Yoshiki,Agawa, Toshio
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- REACTION OF SULFUR DIOXIDE WITH THIOLS CATALYZED BY BORON TRIFLUORIDE ETHERATE. EVIDENCE FOR A POSSIBLE INTERVENTION OF DITHIOSULFITE AS A REACTION INTERMEDIATE.
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The reaction of sulfur dioxide (SO//2) with 1-propanethiol (NPT), 2-propanethiol (IPT), or 2-methyl-2-propanethiol (TBT) catalyzed by boron trifluoride ethrate (BF//3OEt//2) was investigated. The ratios of dialkyl trisulfide to dialkyl disulfide obtained (RSSSR/RSSR) at an early stage of the reaction were larger than 1 for the reaction of TBT and less than 1 for the reaction of NPT or IPT. The reaction of dithiosulfites with BF//3OEt//2 in the presence or absence of thiol was investigated. From a consideration of the similarity of the composition of the sulfides formed in the reaction of dithiosulfites with BF//3OEt//2 to those in the reaction of SO//2 witn thiol in the presence of BF//3OEt//2, the possibility of the intervention of dithiosulfite as a reaction intermediate in the reaction of SO//2 with thiol is discussed.
- Akiyama
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- Reduction of sulfur with borohydride exchange resin in methanol: Application to rapid and selective synthesis of disulfides
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A convenient and rapid method for the synthesis of symmetrical disulfides from alkyl or aryl alkyl halides using sulfurated borohydride exchange resin (SBER) under anhydrous conditions is described. Selective transfer of sulfur to an alkyl group rather than an aryl group is achieved using this methodology.
- Bandgar,Uppalla,Sadavarte
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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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- Thiol Anions in Nucleiphilic Aromatic Substitution Reactions with Activated Aryl Halides. Attack on Carbon vs Attack on Halogen
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The reaction of o-iodonitrobenzene with thiol anions (RSNa, R = Me, 2-Pr, t-Bu) in 2-propanol solution produces the o-nitrophenyl thioether and nitrobenzene in relative proportions and with rates which depend on R.The results of kinetic analysis and of D-incorporation experiments are inconsistent with a radical chain mechanism as proposed earlier for the alkoxide-promoted hydro-de-halogenation of aryl halides.The data clearly indicate the involvement of a carbanionic intermediate (the o-nitrophenyl anion) and are consistent with a stepwise mechanism in which the first step is nucleophilic attack on iodine to form a sulphenyl halide and the o-nitrophenyl anion (a halogenophilic reaction).In contrast, the reaction of the other o-halonitrobenzenes (F, Cl, Br) produces exclusively the product of alkylthio-de-halogenation according to the addition/elimination (SNAr) mechanism.The fact that in these systems the reactivity of thiol anions results from their ability as bielectronic nucleophiles rather than as reducing agents is discussed.
- Montanari, Stefano,Paradisi, Cristina,Scorrano, Gianfranco
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- Photocatalytic Aerobic Thiol Oxidation with a Self-Sensitized Tellurorhodamine Chromophore
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Aerobic oxidation of thiols to disulfides was achieved photocatalytically using a tellurorhodamine chromophore (9-mesityl-3,6-bis(dimethylamino)telluroxanthylium hexafluorophosphate) as both the sensitizer and catalyst. The proposed mechanism, supported experimentally and computationally with DFT, involves the formation of a tellurorhodamine telluroxide from reaction with water and singlet oxygen generated by irradiation of the tellurorhodamine. The oxidation to the telluroxide is accompanied by the formation of hydrogen peroxide. The telluroxide oxidizes thiols to regenerate the tellurorhodamine and the disulfide plus water. Mechanistically, DFT suggests adding two thiols to the telluroxide with the loss of H2O to give a trigonal-bipyramidal Te(IV), which undergoes concerted loss of disulfide to regenerate 1. Oxidation of thiophenol and 2-naphthalenethiol was complete after 2 h of irradiation with visible light under atmospheric conditions. Oxidation of the electron-poor 2,6-dichlorothiophenol, the sterically bulky tert-butylmercaptan, and aliphatic dodecanethiol was slower. The two aliphatic thiols displayed competing catalyst degradation. The corresponding selenorhodamine chromophore (9-mesityl-3,6-bis(dimethylamino)selenoxanthylium hexafluorophosphate) does not form the corresponding selenoxide under similar conditions and photooxidizes thiophenol and 2-naphthalenethiol much more slowly (≤6% conversion after 2-3 h).
- Lutkus, Luke V.,Rettig, Irving D.,Davies, Kellie S.,Hill, Jacqueline E.,Lohman, James E.,Eskew, Mathew W.,Detty, Michael R.,McCormick, Theresa M.
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- Study on the basic centers and active oxygen species of solid-base catalysts for oxidation of iso-mercaptans
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It is a challenge to remove mercaptans as well as to keep octane value in clean gasoline production. In this work, gas-liquid-solid heterogeneous base-catalyzed oxidation of tert-butyl thiol by molecular oxygen was investigated. The reactivity and stability of modified MgO catalysts were studied. The catalysts were further characterized by XRD, FT-IR, CO 2-TPD, H2-TPD, O2-TPD and EPR. Compared with commercial cobalt phthalocyanine catalyst (CoPc catalyst), the modified MgO catalyst displayed an enhanced stability to the oxidation of tert-butyl thiol, and the catalytic lifetime is 10 h longer than that of CoPc catalyst at 3.0 h-1 of LHSV. It was found that the active sites of the catalysts are defects and basic centers. In addition, the basic sites responsible for the reactivity are mainly the medium and strong basic centers. It is interesting that the part of O3C2 - Mg3C2+ provides medium basic centers, however, the other part of it supplies as strong basic centers. It was demonstrated that superoxide anions O2- served as the active oxygen species.
- Zhang, Yufen,Liu, Zhenyi,Ren, Shenyong,Wang, Wennian,Shen, Baojian
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- Theoretical and electrochemical analysis of dissociative electron transfers proceeding through formation of loose radical anion species: Reduction of symmetrical and unsymmetrical disulfides
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The dissociative reduction of a series of symmetrical (RSSR, R = H, Me, t-Bu, Ph) and unsymmetrical disulfides (RSSR′, R = H, R′ = Me and R = Ph, R′ = Me, t-Bu) was studied theoretically, by MO ab initio calculations and, for five of them, also experimentally, by convolution voltammetry in N,N-dimethylformamide. The reduction is dissociative but proceeds by a stepwise mechanism entailing the formation of the radical anion species. The electrochemical data led to estimated large intrinsic barriers, in agreement with an unusually large structural modification undergone by the disulfide molecules upon electron transfer. The theoretical results refer to MP2/3-21G*//MP2/3-21G*, MP2/3-21*G*//MP2/3-21G*, CBS-4M, and G2(MP2), the latter approach being used only for the molecules of small molecular complexity. A loose radical-anion intermediate was localized and the dissociation pattern for the relevant bonds analyzed. For all compounds, the best fragmentation pathway in solution is cleavage of the S-S bond. In addition, S-S bond elongation is the major structural modification undergone by the disulfide molecule on its way to the radical anion and eventually to the fragmentation products. The calculated energy of activation for the initial electron transfer was estimated from the crossing of the energy profiles of the neutral molecule and its radical anion (in the form of Morse-like potentials) as a function of the S-S bond length coordinate. The inner intrinsic barrier obtained in this way is in good agreement with that determined by convolution voltammetry, once the solvent effect is taken into account.
- Antonello, Sabrina,Benassi, Rois,Gavioli, Giovanna,Taddei, Ferdinando,Maran, Flavio
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- THE CATALYTIC OXIDATION OF TIOLS TO DISULFIDES BY THE CLUSTER 2- AND ASSOCIATED LIGAND EFFECTS
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The cluster (nBu4N)2, the analogue of the active site of nonheme iron-sulfur proteins, catalyzed the oxidation of thiols to disulfides extremly and the ligand effects for the catalytic oxidation were investigated.
- Nagano, Tetsuo,Yoshikawa, Kazumasa,Hirobe, Masaaki
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- A Mild, High-Yield Conversion of Thiols into Disulfides Using Disulfide Dication Salt: A New Redox System
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A new redox reaction of thiols with disulfide dication salt, 1,5-dithioniabicyclooctane bis(trifluoromethanesulfonate), under mild conditions gave the corresponding disulfides in good yields together with 1,5-dithiacyclooctane.
- Fujihara, Hisashi,Akaishi, Ryouichi,Furukawa, Naomichi
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- Fast and efficient green synthesis of thiosulfonate S-esters by microwave-supported permanganate oxidation of symmetrical disulfides
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Potassium permanganate absorbed on copper(II) sulfate pentahydrate has been found to be an efficient, inexpensive, and green oxidation agent for the synthesis of "symmetrical" thiosulfonate S-esters by oxidation of the corresponding symmetrical disulfides. The oxidation reactions were carried out under solvent-free reaction conditions within 15 min under the influence of microwave irradiation, as well as (for comparison) supported by conventional heating, to afford yields of the thiosulfonate S-esters in the range of 60-83%. The oxidation reaction appears to proceed (at least partly) via an intermediate symmetrical vic-disulfoxide.
- Luu, Thi Xuan Thi,Nguyen, Thao-Tran Thi,Le, Thach Ngoc,Spanget-Larsen, Jens,Duus, Fritz
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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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- Glutathione peroxidase mimics based on conformationally-restricted,peri-like, 4,5-disubstituted fluorene dichalcogenides
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Glutathione peroxidase (GPx) regulates cellular peroxide levels through glutathione oxidation. GPx-mimics based on 4,5-disubstituted fluorene diselenides, their oxides, and ditellurides show catalytic activities consistent with conformational restriction
- Capperucci, Antonella,Figliola, Carlotta,Grainger, Richard S.,Jagdev, Kesar,Lownes, Jack W.,Male, Louise,Tanini, Damiano
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supporting information
p. 10565 - 10569
(2021/12/27)
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- Phototropin-Inspired Chemoselective Synthesis of Unsymmetrical Disulfides: Aerobic Oxidative Heterocoupling of Thiols Using Flavin Photocatalysis
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Inspired by the photochemical mechanism of a plant blue-light receptor, a unique flavin-based photocatalytic system was developed for the chemoselective heterocoupling of two different thiols, which enabled the facile synthesis of unsymmetrical disulfides. Owing to the redox- and photo-organocatalysis of flavin, the coupling reaction took place under mild metal-free conditions and visible light irradiation with the use of air, which is recognized as the ideal green oxidant.
- Iida, Hiroki,Katsube, Daichi,Oka, Marina,Tsuji, Takeshi
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supporting information
p. 9244 - 9248
(2020/12/21)
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- THIO(DI)SILANES
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Thio(di)silanes comprising a thiosilane of formula (A): (R1aR1bR1cCS)s(Si)XxHh (A) wherein subscript s is from 2 to 4 or a thiodisilane of formula (I): (R1aR1bR1cCS)s(R22N)(Si—Si)XxHh (I) wherein subscript s is from 1 to 6, and wherein R1a, R1b, R1c, R2, X and subscripts n, x and h are defined herein. Also compositions comprising same, methods of making and using same, intermediates useful in synthesis of same, films and materials prepared therefrom.
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Paragraph 0081; 0087
(2020/02/10)
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- Preparation method of tert-butyl disulfide
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The invention discloses a preparation method of tert-butyl disulfide, and the method comprises the following steps: reacting di-tert-butyl sulfite with a disodium disulfide solution, and purifying toobtain the product. According to the method, the di-tert-butyl sulfite is used as a raw material; according to an existing route, tert-butyl mercaptan or tert-butyl chloride is generally adopted as araw material; compared with the existing route, the method has innovative advantages, the raw materials for preparing the di-tert-butyl sulfite are low in price and easy to purchase; moreover, the smell is small and easy to control, the whole reaction condition is mild, the post-treating operation is simple, the production can be carried out only by using conventional equipment, and the problems of large production smell, difficult treating of the environment, high production cost and unsuitability for industrial production in the existing method are solved.
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Page/Page column 4; 5
(2020/08/02)
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- T BuOK-triggered bond formation reactions
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Recently, inexpensive and readily available tBuOK has seen widespread use in transition-metal-free reactions. Herein, we report the use of tBuOK for S-S, S-Se, NN and CN bond formations, which significantly extends the scope of tBuOK in chemical synthesis. Compared with traditional methods, we have realized mild and general methods for disulfide, azobenzenes imine etc. synthesis.
- Xu, Yulong,Shi, Xiaonan,Wu, Lipeng
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p. 24025 - 24029
(2019/08/13)
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- The solvent-controlled chemoselective construction of C-S/S-S bonds via the Michael reaction/thiol coupling of quinoline-2-thiones
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K2CO3-catalyzed thio-Michael addition using quinoline-2-thiones and α,β-unsaturated carbonyl compounds was used to assess the chemoselective construction of C-S and S-S bonds under mild reaction conditions in different solvents. The C-S bond showed a better chemoselective construction in EtOH whereas the S-S bond showed a better chemoselective construction in 1,4-dioxane. The corresponding products, generated from the reaction, presented a significant solvent-controlling effect.
- Zhang, Xi,Wang, Tong-Lin,Liu, Xiao-Jun,Wang, Xi-Cun,Quan, Zheng-Jun
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supporting information
p. 2379 - 2383
(2019/03/06)
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- A rapid, efficient and green procedure for transformation of alkyl halides/ tosylates to organochalcogens in water
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A one-pot and efficient synthesis of dialkyl dichalcogenides (S, Se) in aqueous media under catalyst-free conditions using benzylic, allylic and primary halides with elemental sulfur and selenium has been developed. Also, this procedure was extended to preparation of trisulfides and triselenides from secondary and tertiary halides in same condition. In all cases, products can be obtained in good to excellent yield in short reactions time.
- Soleiman-Beigi, Mohammad,Yavari, Issa,Sadeghizadeh, Fatemeh
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- Photo-induced thiol coupling and C-H activation using nanocrystalline lead-halide perovskite catalysts
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The use of photon energy to promote chemical transformations offers versatile control of reaction kinetics and progress. Over the past decade, many photoactive transition-metal complexes and organic chromophores were developed to catalyze chemical transformations, enabling a myriad of reactions and compounds that were previously inaccessible via traditional synthetic methods. Here, we demonstrate the photocatalytic oxidative coupling of organic thiols using cesium lead halide perovskite nanocrystals as photocatalysts. The photo-catalyzed thiol coupling reactions selectively produced symmetric and unsymmetrical disulfides in high yields (68-96% isolated yields). Additionally, we discovered a perovskite-catalyzed phosphonylation of tertiary amines via visible-light-mediated cross-dehydrogenative coupling reaction, and obtained good isolated yields (50-96%). The variety of visible-light-induced photocatalytic processes that perovskite nanocrystals are capable of, coupled with their facile preparation, easily tunable redox potentials, high catalytic efficiency and reusability, presents great opportunities for their future applications in green and sustainable organic synthesis.
- Wu, Wen-Bin,Wong, Ying-Chieh,Tan, Zhi-Kuang,Wu, Jie
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p. 4257 - 4263
(2018/08/24)
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- Europhtal (8020) efficiently catalyzes the aerobic oxidation of in situ generated thiols to symmetric disulfides (disulfanes)
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Efficient, odorless and scalable synthetic protocols have been introduced for the preparation of symmetric alkyl disulfides by treatment of the corresponding organic halides with thiourea and NaHCO3in the presence of commercially available Europhtal catalyst (8020) in both H2O and poly ethylene glycol (PEG-200) media at 80–90 °C. Structurally diverse primary, secondary, allylic and benzylic halides were examined successfully whereas, the result with tert-butyl bromide was not satisfactory. Also, another procedure has been introduced for achieving symmetric aryl disulfides in high yields by reacting aryl halides, thiourea and NaHCO3in PEG-200 at 115–120 °C using CuI along with Europhtal catalysts. The results showed that the aerobic oxidation of in situ generated thiols proceeded efficiently in the presence of Europhtal catalyst giving the symmetric disulfide without contamination by symmetric sulfide side-product.
- Abbasi, Mohammad,Sabet, Askar,Sabet, Askar
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- Conversion of organic halides to disulfanes using KCN and CS2
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A sulfur transfer reagent was produced in situ upon stirring a mixture of KCN and CS2 in DMF at r.t. for 15 min, which after heating with an alkyl halide or aryl halide and CuI gave the corresponding symmetric dialkyl or diaryl disulfide, respectively, in high to excellent yields.
- Abbasi, Mohammad,Nowrouzi, Najmeh,Borazjani, Saeedeh Ghassab
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p. 4251 - 4254
(2017/10/11)
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- Process for synthesizing chiral tert-butanesulfinyl amide
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The invention discloses a process for synthesizing chiral tert-butanesulfinyl amide. The process includes carrying out reaction on tert-butyl mercaptan and iodine/hydrogen peroxide acetone to generate di-tert-butyl disulfide; oxidizing hydrogen peroxide under the catalytic effect of vanadium to generate chiral tert-butyl sulfenyl tert-butyl mercaptide; carrying out one-pot reaction on the chiral tert-butyl sulfenyl tert-butyl mercaptide and lithium reagents/liquid ammonia in the presence of alkyl chloride to obtain the tert-butanesulfinyl amide. Compared with existing processes, the process has the advantages that the smoothness of the process can be enhanced, the usage of the liquid ammonia can be reduced to a great extent, and the operational efficiency can be improved.
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Paragraph 0016; 0018; 0020
(2017/08/28)
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- Method for preparing tert-butyl disulfide
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The invention provides a method for preparing tert-butyl disulfide by enabling tert-butyl mercaptan and sodium hydroxide to form salt, and enabling the salt to react with sulfur powder. According to the technical scheme adopted by the invention, the tert-butyl mercaptan, alkaline liquor and the sulfur powder react in a solvent of isopropanol at a temperature of 50-60 DEG C to generate a product tert-butyl disulfide by a one-pot method; water in reaction liquor is separated out by post-treatment; an oil layer is distilled and separated to obtain the target product tert-butyl disulfide; separated-out water is added with sodium hypochlorite to be subjected to neutralizing treatment, so that the sodium hypochlorite is reduced into sodium hydroxide and sulfur powder; and the tert-butyl mercaptan is directly added in a supplemented mode, so that wastewater is used indiscriminately. The method adopts easily available raw materials, is simple to operate, is safe and environmentally friendly, is relatively low in cost, and is relatively high in yield, and is a proper method for preparing the tert-butyl disulfide.
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Paragraph 0015-0030
(2017/08/31)
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- Thiol Reactivity toward Atomic Oxygen Generated during the Photodeoxygenation of Dibenzothiophene S-Oxide
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Aromatic heterocyclic oxides, such as dibenzothiophene S-oxide (DBTO), have been suggested to release ground state atomic oxygen [O(3P)] upon irradiation, and as such, they have been used to create a condensed phase reactivity profile for O(3P). However, thiols, which are highly reactive with O(3P) in the gas phase, were not previously investigated. An earlier study of O(3P) with proteins in solution indicated a preference for thiols. A further investigation of the apparent thiophilicity provided the subject for this study. DBTO was employed as a putative O(3P)-precursor. However, the effective rate of O(3P) formation was found to be dependent on reactant concentrations in certain cases. All reactants were found to increase the rate of deoxygenation to some extent, but in the presence of reactants containing an alcohol linked to a reactive functional group, deoxygenation occurred substantially more rapidly. The rate enhancement was quantified and attributed to the reaction of activated O atom within the solvent cage prior to escape into the bulk solution. Through competition experiments, the relative rate constants of O(3P) with thiols and other functional groups were found. A small preference for primary thiols was observed over other thiols, sulfides, and alkenes. A much larger preference was observed for thiols, sulfides, and alkenes over aromatic groups. In summary, DBTO was successfully used as an O(3P)-precursor, and the thiophilicity of O(3P) was confirmed and quantified.
- Omlid, Sara M.,Zhang, Miao,Isor, Ankita,McCulla, Ryan D.
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p. 13333 - 13341
(2017/12/15)
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- One-pot conversion of alkyl halides to organic disulfides (disulfanes) using thiourea and hexamethyldisilazane (HMDS) in DMSO
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A practical method to synthesize symmetric disulfides from alkyl halides has been developed. Using this procedure primary, secondary, benzylic and allylic disulfides were prepared by treating the corresponding alkyl halides with thiourea and HMDS in DMSO at 50 °C within 10-24 h in high yields.
- Abbasi, Mohammad,Jabbari, Arida
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- One-pot synthesis of organic disulfides (disulfanes) from alkyl halides using sodium sulfide trihydrate and hexachloroethane or carbon tetrachloride in the poly(ethylene glycol) (PEG-200)
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Abstract Symmetric disulfides are produced by treating their corresponding organic halides including benzylic, allylic, primary and secondary halides with Na2S·3H2O and C2Cl6 or CCl4 in PEG-200 at room temperature in high yields.
- Abbasi, Mohammad,Mohammadizadeh, Mohammad Reza,Moosavi, Hekmat,Saeedi, Narges
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p. 1185 - 1190
(2015/03/31)
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- Ultrasound-Accelerated Synthesis of Asymmetrical Thiosulfonate S-Esters by Base-Promoted Reaction of Sulfonyl Chlorides with Thiols
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Amberlyst A-26, Mg-Al hydrotalcite, potassium fluoride absorbed on alumina, triethylamine and pyridine have been tested as base catalysts and reagents for the reaction of sulfonyl chlorides with thiols to prepare thiosulfonate S-esters. The reactions were performed under solvent-free conditions or with a minimum amount of solvent assisted by magnetic stirring, ultrasound irradiation and microwave irradiation. Ultrasound irradiation has good effects on the synthesis of sterically hindered thiosulfonate S-esters in solvent-free media as well as in a minimum amount of anhydrous diethyl ether.
- Pham, Hien Thi,Nguyen, Ngoc-Lan Thi,Duus, Fritz,Luu, Thi Xuan Thi
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p. 1934 - 1941
(2015/12/12)
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- Efficient ruthenium-catalysed S-S, S-Si and S-B bond forming reactions
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[RuCl(PPh3)2(3-phenylindenyl)] (1) has been shown to be an efficient catalyst in thiol dehydrogenative coupling to give disulfides. Moreover, an efficient procedure for the preparation of silylthioethers and thioboranes is presented. Complex 1 demonstrated a great ability to catalyse the coupling of thiols with silanes and boranes under mild conditions with excellent results (turnover number up to 200).
- Fernandez-Salas, Jose A.,Manzini, Simone,Nolan, Steven P.
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supporting information
p. 5829 - 5831
(2013/07/19)
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- Copper(I) nitrosyls from reaction of copper(II) thiolates with S-nitrosothiols: Mechanism of NO release from RSNOs at Cu
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S-nitrosothiols (RSNOs) serve as ready sources of biological nitric oxide activity, especially in conjunction with copper centers. We report a novel pathway for the generation of NO within the coordination sphere of copper model complexes from reaction of copper(II) thiolates with S-nitrosothiols. Reaction of tris(pyrazolyl)borate copper(II) thiolates iPr2TpCu-SR (R = C 6F5 or CPh3) with tBuSNO leads to formation of iPr2TpCu(NO) and the unsymmetrical disulfide RS-S tBu. Quantum mechanical investigations with B3LYP-D3/6-311G(d) suggest formation of a κ1-N-RSNO adduct iPr2TpCu(SR) (R′SNO) that precedes release of RSSR′ to deliver iPr2TpCu(NO). This process is reversible; reaction of iPr2TpCu(NO) (but not iPr2TpCu(NCMe)) with C 6F5S-SC6F5 forms iPr2TpCu-SC6F5. Coupled with the facile, reversible reaction between iPr2TpCu(NO) and C6F 5SNO to give iPr2TpCu-SC6F5 and 2 equiv NO, we outline a new, detailed catalytic cycle for NO generation from RSNOs at Cu.
- Zhang, Shiyu,Celebi-Oelcuem, Nihan,Melzer, Marie M.,Houk,Warren, Timothy H.
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supporting information
p. 16746 - 16749
(2013/12/04)
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- Base-free oxidation of thiols to disulfides using selenium ionic liquid
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We present here the results on the use of 1-n-butyl-3-methylimidazolium methylselenite, [bmim][SeO2(OCH3)], in the synthesis of symmetrical disulfides starting from thiols. This efficient and improved method is general for aromatic, aliphatic, and functionalized thiols affording the disulfides in good to excellent yields after easy work up. The use of a microwave accelerates the reaction and the [bmim][SeO2(OCH 3)] was reused for further oxidation reactions.
- Thurow, Samuel,Pereira, Vanda A.,Martinez, Débora M.,Alves, Diego,Perin, Gelson,Jacob, Raquel G.,Lenard?o, Eder J.
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experimental part
p. 640 - 643
(2011/02/28)
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- Aerobic oxidation of thiols to disulfides catalyzed by diaryl tellurides under photosensitized conditions
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Aerobic oxidation of thiols is efficiently catalyzed by diaryl tellurides such as bis(4-methoxyphenyl) telluride under photosensitized conditions to give the corresponding disulfides in good to excellent yields. In this catalytic system, the tellurone oligomer, produced by the reaction of a telluride with singlet oxygen, is assumed to be the active species and is capable of oxidizing 4 equiv of a thiol.
- Oba, Makoto,Tanaka, Kazuhito,Nishiyama, Kozaburo,Ando, Wataru
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experimental part
p. 4173 - 4177
(2011/06/26)
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- A one-pot, efficient, and odorless synthesis of symmetrical disulfides using organic halides and thiourea in the presence of manganese dioxide and wet polyethylene glycol (PEG-200)
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Primary, secondary, tertiary, allylic, and benzylic halides are converted efficiently into symmetric disulfides in high yields using thiourea as the sulfur atom source. The reactions are odorless and are performed at 30-35 °C in wet PEG-200 using MnO2 as an oxidant.
- Firouzabadi, Habib,Iranpoor, Nasser,Abbasi, Mohammad
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experimental part
p. 508 - 509
(2010/10/02)
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- Easy and rapid method for disulfide syntheses using nanophase-manganese (VII) oxide coated clay
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Disulfide bond formation by the oxidation of several thiol compounds using nanophase manganese (VII) oxide coated clay (NM7O coated clay) in chlorinated, nonchlorinated (toluene), and polar solvents (water) is described. During the process, nitro and methoxy groups remain unaffected. The NM7O coated clay is easily prepared, stable, and inexpensive to manufacture. Furthermore, this and other studies prove that NM7O coated clay properties, i.e., mineralogy, chemical, and reactivity, are different from KMnO4. This rapid and facile synthesis coupled with the use of the recyclable NM7O coated clay catalyst will save energy due to low temperature and rapid reaction times, as well as minimal disposal problems, thus decreasing production costs.
- Gondi, Sudershan R.,Son, David Y.,Biehl, Edward R.,Vempati, Rajan K.
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scheme or table
p. 34 - 39
(2010/05/02)
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- An improved method for the synthesis of disulfides by periodic acid and sodium hydrogen sulfite in water
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An improved method for the synthesis of disulfide in water by using periodic acid and sodium hydrogen sulfite was developed.
- Khan, Khalid M.,Taha, Muhammad,Rahim, Fazal,Ali, Muhammad,Jamil, Waqas,Perveen, Shahnaz,Iqbal Choudhary
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experimental part
p. 415 - 419
(2011/03/22)
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- Reductive metalation of cyclic and acyclic pseudopeptidic bis-disulfides and back conversion of the resulting diamidato/dithiolato complexes to bis-disulfides
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Cyclic and acyclic pseudopeptidic bis-disulfides built on an o-phenylene diamine scaffold were prepared: (N2H2S2) 2, 1a, N2H2(S-SCH3)2, 1b, and N2H2(S-StBu)2, 1c. Reductive metalation of these disulfides with (PF6)[Cu(CH3CN)4] in the presence of Et4NOH as a base, or with (Et4N)[Fe(SEt) 4] and Et4NCl, yields the corresponding diamidato/dithiolato copper(III) or iron(III) complex, (Et4N) [Cu(N2S2)], 2, or (Et4N)2[Fe(N 2S2)Cl], 5. These complexes display characteristics similar to those previously described in the literature. The mechanism of the metalation with copper has been investigated by X-band electron paramagnetic resonance (EPR) spectroscopy at 10 K. After metalation of the bis-disulfide 1c and deprotonation of the amide nitrogens, the reductive cleavage of the S-S bonds occurs by two one-electron transfers leading to the intermediate formation of a copper(II) complex and a thyil radical. Complexes 2 and 5 can be converted back to the cyclic bis-disulfide 1a with iodine in an 80% yield. Reaction of 5 with iodine in the presence of CH3S-SCH3 affords a 1/1 mixture of the acyclic N2H2(S-SCH3)2 disulfide 1b and cyclic bis-disulfide 1a. From 2, the reaction was monitored by 1H NMR and gives 1b as major product. While there is no reaction of 2 or 5 with tBuS-StBu and iodine, reaction with an excess of tBuSI affords quantitatively the di-tert-butyl disulfide 1c. To assess the role of the Cu III oxidation state, control experiments were carried out under strictly anaerobic conditions with the copper(II) complex, (Et 4N)2[Cu(N2S2)], 6. Complex 6 is oxidized to 2 by iodine, and it reacts with an excess of tBuSI, yielding 1c as final product, through the intermediate formation of complex 2.
- Desbenoit, Nicolas,Galardon, Erwan,Frapart, Yves,Tomas, Alain,Artaud, Isabelle
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scheme or table
p. 8637 - 8644
(2010/12/24)
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- Enantioselective synthesis, configurational stability, and reactivity of lithium α-tert-butylsulfonyl carbanion salts
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The reactions of enantiopure S-tert-butyl sulfones of the type R 1CH(R2)SO2tBu (≥99% ee) with lithiumorganyl compounds gave the corresponding chiral α-sulfonyl carbanion salts [R 1C(R2)SO2tBu]Li with ≥94% ee. The enantioselectivity of the deprotonation of the phenyl- but not dialkyl-substituted sulfones is strongly dependent on the nature of the lithiumorganyl. Because of this observation and the strong decrease in enantioselectivity in the presence of TMEDA and HMPA, we propose an intramolecular proton transfer following complexation of the sulfone by RLi. Racemization of [R1C(R2)-SO2tBu]Li follows first-order kinetics and seems to be mainly an enthalpic process with a small negative activation entropy, as revealed by polarimetric measurements at low temperatures. This is in accordance with Cα-S bond rotation as the rate-determining step. The salts [R1C(R2)SO 2tBu]Li have half-lives of racemization in the order of several hours at -105°C. The deuteriation of the salts at -105°C with CF 3CO2D proceeded with enantioselectivities of 94% ee, the magnitude of which was not significantly affected by the presence of TMEDA and HMPA. The salts also reacted with carbon-based electrophiles at low temperatures with high enantioselectivity. The conversion of R1CH(R 2)SO2tBu via [R1C(R2)SO 2tBu]Li to R1C(R2,E)SO2tBu, which involves the loss of stereogenicity at the α-stereogenic center and its reestablishment upon reaction of the chiral carbanion with electrophiles, occurred with high overall enantioselectivity. Electrophiles attack the anionic C atom of [R1C(R2)SO2tBu]Li with high selectivity on the side syn to the O atoms and anti to the tert-butyl group. The reactivity of the dialkyl-substituted salts [R1C(R 2)SO2tBu]Li (R1, R2 = alkyl) is significantly higher than that of the benzylic salts [RC(Ph)SO2tBu]Li (R = alkyl) and the HMPA-coordinated SIPs of [MeC(Ph)SO2- tBu]Li are significantly more reactive towards EtI than the corresponding O-Li contact ion pairs.
- Scholz, Roland,Hellmann, Gunther,Rohs, Susanne,Oezdemir, Diana,Raabe, Gerhard,Vermeeren, Cornelia,Gais, Hans-Joachim
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supporting information; experimental part
p. 4588 - 4616
(2010/10/21)
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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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- A mild and alternative approach towards symmetrical disulfides using H 3IO5/NaHSO3 combination
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Treatment of thiols with a mixture of periodic acid/sodium hydrogen sulfite gave the corresponding disulfides in good yield.
- Khan, Khalid M.,Taha, Muhammad,Ali, Muhammad,Perveen, Shahnaz
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experimental part
p. 319 - 320
(2010/04/23)
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- Efficient oxidative coupling of thiols into disulfides using N-tert-butyl-N-chlorocyanamide
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Reaction of aliphatic/aromatic/heterocyclic thiols with N-tert-butyl-N-chlorocyanamide in presence of sodium bromide is described. The reaction was very rapid and resulted in the formation of disulfides in excellent yields under mild conditions.
- Kumar, Vinod,Kaushik, Mahabir Parshad
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experimental part
p. 160 - 162
(2009/04/06)
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- Process for the Removal By Oxidation, of Mercaptans Contained in Hydrocarbons
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The mercaptans R—SH contained in a hydrocarbon stream are oxidized to the corresponding (di)sulfides by means of a redox system which comprises trivalent iron and a heteropolyacid which allows the complete reoxidation of the reduced iron also with air.
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Page/Page column 3
(2009/05/29)
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- Unexpected reactivity of the Burgess reagent with thiols: Synthesis of symmetrical disulfides
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(Equation Presented) Reaction of the Burgess reagent with a series of aliphatic and aromatic thiols led to the corresponding symmetrical disulfides in high yields. No olefins were detected in the reactions of aliphatic thiols.
- Banfield, Scott C.,Omori, Alvaro Takeo,Leisch, Hannes,Hudlicky, Tomas
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p. 4989 - 4992
(2008/02/05)
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- Inexpensive, one-pot synthesis of unsymmetrical disulfides using 1-chlorobenzotriazole
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A new synthesis of unsymmetrical disulfides is described. The reaction of a thiol R1SH with 1-chlorobenzotriazole (BtCl) at -78 °C in DCM affords a high-yielding conversion to R1SBt without appreciable formation of the symmetrical disulfide R1SSR1. R1SBt is then reacted with R2SH to form the unsymmetrical disulfide in a one-pot sequence with green character that avoids the use of toxic and harsh oxidizing agents. The methodology has been developed for synthesis of various types of disulfides.
- Hunter, Roger,Caira, Mino,Stellenboom, Nashia
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p. 8268 - 8271
(2007/10/03)
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- A novel example of vinylic SRN1: Reactions of 3,3-difluoro-1-iodo-2-phenylcyclopropene with thiolate ions
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The reactions of 3,3-difluoro-1-iodo-2-phenylcyclopropene with thiolate ions (with a molar ratio of 1:1) were carried out in laboratory illumination to give the corresponding substituted product. The presence of p-dinitrobenzene (p-DNB) or hydroquinone (HQ) as well as darkness significantly suppressed the reaction. ESR trapping experiments also evidenced the existence of fluorinated radical. All these results demonstrate the reaction involved a vinylic saturated alkyl and aromatic halides (SRN1) mechanism.
- Zhou, Ding-Ying,Dou, Hong-Yan,Zhao, Cheng-Xue,Chen, Qing-Yun
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p. 740 - 745
(2008/03/28)
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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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- A new reagent for the efficient synthesis of disulfides from alkyl halides
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Benzyltriethylammonium tetracosathioheptamolybdate [(C6H5CH2N(Et)3)6Mo 7S24] has been found to be a superior sulfur transfer reagent for the conversion of alkyl halides to the corresponding disulfides in excellent yields under very mild reaction conditions.
- Polshettiwar, Vivek,Nivsarkar, Manisha,Acharya, Jyotiranjan,Kaushik
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p. 887 - 889
(2007/10/03)
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- A kinetic study of S-nitrosothiol decomposition
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Under anaerobic conditions S-nitrosothiols 1a-e undergo thermal decomposition by homolytic cleavage of the S-N bond; the reaction leads to nitric oxide and sulfanyl radicals formed in a reversible manner. The rate constants, k1, have been determined at different temperatures from kinetic measurements performed in refluxing alkane solvents. The tertiary nitrosothiols 1c (k1(69°C) = 13 × 10-3 min-1) and 1d (k1(69°C) 91 × 10-3 min-1) decomposed faster than the primary nitrosothiols 1a (k1(69°C) = 3.0 × 10-3 min-1) and 1b (k1(69°C) = 6.5 × 10-3 min-1). The activation energies (E#= 20.5 - 22.8 Kcal mol-1) have been calculated from the Arrhenius equation. Under aerobic conditions the decay of S-nitrosothiols 1a-e takes place by an autocatalytic chain-decomposition process catalyzed by N2O3. The latter is formed by reaction of dioxygen with endogenous and/or exogenous nitric oxide. The autocatalytic decomposition is strongly inhibited by removing the endogenous nitric oxide or by the presence of antioxidants, such as pcresol, β-styrene, and BHT The rate of the chain reaction is independent of the RSNO concentration and decreases with increasing bulkiness of the alkyl group; this shows that steric effects are crucial in the propagation step.
- Grossi, Loris,Montevecchi, Pier Carlo
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p. 380 - 387
(2007/10/03)
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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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- Tetrabutylammonium peroxydisulfate in organic synthesis. XII. A convenient and practical procedure for the selective oxidation of thiols to disulfides with tetrabutylammonium peroxydisulfate under solvent-free conditions
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An efficient method for the oxidative coupling of thiols to their corresponding disulfide by (n-Bu4N2)S2O8 in high yields under solvent-free conditions is described. The reaction was applicable to a variety of thiols with high chemoselectivity.
- Chen, Fen-Er,Lu, Yun-Wen,He, Yan-Ping,Luo, You-Fu,Yan, Ming-Guo
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p. 3487 - 3492
(2007/10/03)
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- Simple and selective oxidation of thiols to disulfides with dimethylsulfoxide catalyzed by dichlorodioxomolybdenum(VI)
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Selective and quantitative conversion of thiols to disulfides was effected by dimethyl sulfoxide under mild conditions catalyzed by dichlorodioxomolybdenum(VI).
- Sanz, Roberto,Aguado, Rafael,Pedrosa, María R.,Arnáiz, Francisco J.
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p. 856 - 858
(2007/10/03)
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- S-nitrosothiol and disulfide formation through peroxynitrite-promoted oxidation of thiols
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Peroxynitrite reacts with thiols 1 at acidic pH to give the corresponding S-nitrosothiols 2 and disulfides 3. The formation of nitrosothiols 2, the yield of which is strongly pH-dependent, can be rationalized in terms of acid-catalyzed decomposition of the undissociated HPN, probably through the intermediacy of the protonated form H2PN+, leading to a species, X-NO, capable of nitrosating the thiol function. In contrast, the formation of disulfides 3 occurs in a manner independent of the pH, without the intermediacy of sulfanyl radicals. Under basic conditions, the peroxynitrite anion (PN) oxidizes the thiolate ion to sulfanyl radicals, eventually leading to disulfide 3, or undergoes a thiol-catalyzed decomposition. The former is the exclusive reaction exhibited by peroxynitrite at pH > 13.
- Grossi, Loris,Montevecchi, Pier Carlo,Strazzari, Samantha
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p. 131 - 135
(2007/10/03)
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