- Reactions of sulfur containing phenolic antioxidants for elastomers
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Alkyl-hydroxybenzylthioethers are efficient storage and processing stabilizers for elastomers and adhesives. Especially alkyl-(2-hydroxybenzyl)thioethers represent an intramolecular combination of a primary and secondary antioxidant, i.e. a phenolic and a thioether moiety in an optimized spatial arrangement. The mechanism of their intramolecular synergism was investigated. The best overall stabilizers are 2,4-bis(alkylthiomethyl)-6-methylphenols, e.g. AOI, in contrast to 2,6-dialkyl-4-alkylthiomethylphenols(B), 4-alkyl-2,6-bis(alkylthiomethyl)phenols C.
- Meier, Hansrudolf,Kuenzi, Hanspeter,Knobloch, Gerrit,Rist, Guenther,Szelagiewicz, Martin
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Read Online
- Regioselective functionalization of gem-bis(trifluoromethylated) alkanols
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One-pot functionalization of sp3 C–H bond in 1,1,1-trifluoro-2-(trifluoromethyl)decan-2-ol with CO and nucleophiles under the action of superelectrophilic complex CBr4·2 AlBr3 affords products of neo-structure and remote functionalities.
- Akhrem, Irena S.,Avetisyan, Dzhul'etta V.,Afanas'eva, Lyudmila V.,Tyutyunov, Andrey A.,Artyushin, Oleg I.,Kagramanov, Nikolai D.
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Read Online
- Palladium-Catalyzed Carbonylative Synthesis of Aryl Selenoesters Using Formic Acid as an Ex Situ CO Source
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A new catalytic protocol for the synthesis of selenoesters from aryl iodides and diaryl diselenides has been developed, where formic acid was employed as an efficient, low-cost, and safe substitute for toxic and gaseous CO. This protocol presents a high functional group tolerance, providing access to a large family of selenoesters in high yields (up to 97%) while operating under mild reaction conditions, and avoids the use of selenol which is difficult to manipulate, easily oxidizes, and has a bad odor. Additionally, this method can be efficiently extended to the synthesis of thioesters with moderate-to-excellent yields, by employing for the first time diorganyl disulfides as precursors.
- Yano De Albuquerque, Danilo,Teixeira, Wystan K. O.,Sacramento, Manoela Do,Alves, Diego,Santi, Claudio,Schwab, Ricardo S.
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supporting information
p. 595 - 605
(2022/01/12)
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- Ashless and non-corrosive disulfide compounds as excellent extreme pressure additives in naphthenic oil
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Medium chain chlorinated paraffin (MCCP) and zinc dialkyl dithiophosphate (ZDDP) are widely used as extreme pressure (EP) additives in metalworking fluids (MWFs). Currently, sulfur-based EP additives are found to be more environmentally friendly and biodegradable. Although naphthenic base oil (NBO) is suitable to be used in MWFs due to its low pour point and better emulsified ability, there is a lack of study on the sulfur additives in this type of oil. In this study, two organo disulfides compounds namely dibenzyl disulfide (DBDS) and dioctyl disulfide (DODS) have been synthesized as EP additives. These DBDS and DODS demonstrate an excellent EP performance, non-corrosive, ashless, and good anti-wear (AW) properties in NBO. The DBDS shows 1961 N (EP value) and 6 mm2 (AW scar area) in NBO, which is superior to DODS, MCCP and ZDDP. This is due to the formation of sulfur-based tribofilm on the interface that acts as a protective sulfur layer thus, enhancing the property of EP.
- Ching Juan, Joon,Ghaffari Khaligh, Nader,Heidelberg, Thorsten,Jiang, Xuefeng,Ling Ong, Chiu
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- Practical and efficient recyclable oxidative system for the preparation of symmetrical disulfides under aerobic conditions
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An efficient and practical oxidative coupling of thiols to symmetrical disulfides is developed at room temperature under aerobic conditions. The commercially available sodium methoxide solution 30 wt. % in methanol together with the air was used as a retrievable promoter system and green oxidant, respectively, for the preparation of symmetrical disulfides. The desired products were obtained in good to high yields by an economical procedure. No overoxidation of the symmetrical disulfides was observed, and various functional groups were well tolerated in the current protocol. Moreover, the new reagent reduces the generation of hazardous waste due to its high reusability. The reaction proceeded in the absence of light, and it was not inhibited by TEMPO. Also, the low yield of TEMPO-benzyl thiol adduct was detected under these conditions. Based on our experiments, a possible mechanism was proposed in the absence and presence of TEMPO.
- Ling, Ong Chiu,Heidelberg, Thorsten,Ching, Juan Joon,Khaligh, Nader Ghaffari
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p. 281 - 294
(2020/12/13)
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- Green Aerobic Oxidation of Thiols to Disulfides by Flavin-Iodine Coupled Organocatalysis
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Coupled catalysis using a riboflavin-derived organocatalyst and molecular iodine successfully promoted the aerobic oxidation of thiols to disulfides under metal-free mild conditions. The activation of molecular oxygen occurred smoothly at room temperature through the transfer of electrons from the iodine catalyst to the biomimetic flavin catalyst, forming the basis for a green oxidative synthesis of disulfides from thiols.
- Iida, Hiroki,Kozako, Ryo,Oka, Marina
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supporting information
p. 1227 - 1230
(2021/06/21)
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- Preparation method of symmetric disulfide bond-containing compound
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The method comprises the following steps: adding a raw material and an oxidant to a reaction bottle containing a solvent; reacting 23W - 85W under the irradiation of 12 - 24h energy-saving lamps; and purifying the reaction product to obtain symmetrical disulfide bond-containing compounds. The raw material is mercaptan or thiophenol. The oxidizing agent is trichlorobromomethane, and the solvent is tetrahydrofuran. The method has the advantages of simple operation, high yield (70 - 90%), wide applicability, cheap and easily available raw materials, and provides a better way for the synthesis and production of symmetrical disulfide bond-containing compounds.
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Paragraph 0020; 0042-0044
(2021/11/21)
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- Visible-light-responsive lanthanide coordination polymers for highly efficient photocatalytic aerobic oxidation of amines and thiols
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Development of visible-light-induced photocatalytic reactions using molecular oxygen as the terminal oxidant is intriguing in view of the current environmental and energy issues. We report herein the synthesis and characterization of a series of novel pho
- An, Shuyi,Guo, Zhifen,Liu, Xin,Che, Yan,Xing, Hongzhu,Chen, Peng
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p. 15767 - 15775
(2021/09/22)
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- Silylating Disulfides and Thiols with Hydrosilicones Catalyzed by B(C6F5)3
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Hydrosilanes and silicones, catalyzed with B(C6F5)3, may be used to silylate thiols or cleave disulfides giving silyl thio ethers. Alcohols were found to react faster than thiols or disulfides, while alkoxysilanes (the Piers-Rubinsztajn reaction) were slower such that the overall order of reactivity was found to be HO>HS>SS>SiOEt. The resulting silane and silicone-protected thio ethers produced from the sulfur-based functional groups could be cleaved to thiols using alcohols or mild acid with rates that depend on the steric bulk of the siloxane.
- Brook, Michael A.,Liao, Mengchen,Zheng, Sijia
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supporting information
p. 2694 - 2700
(2021/06/25)
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- Nanolayered cobalt-molybdenum sulphides (Co-Mo-S) catalyse borrowing hydrogen C-S bond formation reactions of thiols or H2S with alcohols
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Nanolayered cobalt-molybdenum sulphide (Co-Mo-S) materials have been established as excellent catalysts for C-S bond construction. These catalysts allow for the preparation of a broad range of thioethers in good to excellent yields from structurally diverse thiols and readily available primary as well as secondary alcohols. Chemoselectivity in the presence of sensitive groups such as double bonds, nitriles, carboxylic esters and halogens has been demonstrated. It is also shown that the reaction takes place through a hydrogen-autotransfer (borrowing hydrogen) mechanism that involves Co-Mo-S-mediated dehydrogenation and hydrogenation reactions. A novel catalytic protocol based on the thioetherification of alcohols with hydrogen sulphide (H2S) to furnish symmetrical thioethers has also been developed using these earth-abundant metal-based sulphide catalysts.
- Corma, Avelino,Sorribes, Iván
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p. 3130 - 3142
(2019/03/13)
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- Concise and Additive-Free Click Reactions between Amines and CF3SO3CF3
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Trifluoromethyl trifluoromethanesulfonate has proved to be an excellent reservoir of difluorophosgene and a promising click ligation for amines in the preparation of urea derivatives, heterocycles, and carbamoyl fluorides under metal- and additive-free conditions. The reactions are rapid, efficient, selective, and versatile, and can be performed in benign solvents, giving products in excellent yields with minimal efforts for purification. The characteristics of the reactions meet the requirements of a click reaction. The use of trifluoromethyl trifluoromethanesulfonate as a click reagent is advantageous over other “CO” sources (e.g., TsOCF3, PhCO2CF3, CsOCF3, AgOCF3, and triphosgene) because this reagent is readily accessible; easy to scale up; and highly reactive, even under metal- and additive-free conditions. It is anticipated that CF3SO3CF3 will be increasingly as important as SO2F2 as a click agent in future drug design and development.
- Song, Hai-Xia,Han, Zhou-Zhou,Zhang, Cheng-Pan
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supporting information
p. 10907 - 10912
(2019/08/02)
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- Dual-Responsive Photocatalytic Polymer Nanogels
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Selective activation of photocatalysts under constant light conditions has recently been targeted to produce multi-responsive systems. However, controlled activation, with easy recovery of the photocatalysts, induced by external stimuli remains a major challenge. Mimicking the responsiveness of biological systems to multiple triggers can offer a promising solution. Herein, we report dual-responsive polymer photocatalysts in the form of nanogels consisting of a cross-linked poly-N-isopropylacrylamide nanogel, copolymerised with a photocatalytically active monomer. The dual-responsive polymer nanogels undergo a stark decrease in diameter with increasing temperature, which shields the photocatalytic sites, decreasing the activity. Temperature-dependent photocatalytic formation of NAD+ in water demonstrates the ability to switch photocatalysis on and off. Moreover, the photocatalysed syntheses of several fine chemicals were carried out to demonstrate the utility of the designed material.
- Ferguson, Calum T. J.,Huber, Niklas,Landfester, Katharina,Zhang, Kai A. I.
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supporting information
p. 10567 - 10571
(2019/07/09)
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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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- Laccase-catalyzed in situ generation and regeneration of N-phenyltriazolinedione for the aerobic oxidative homo-coupling of thiols to disulfides
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The first report on aerobic in situ generation and regeneration of N-phenyltriazolinedione, a valuable oxidizing agent, from a catalytic amount of N-phenyl urazole in the presence of a laccase enzyme is presented. The application of a 4-phenyl urazole/Laccase/O2 as a new cooperative catalytic oxidation system is reported for a transition-metal-free and halogen free oxidative homo-coupling reaction of structurally diverse thiols to their corresponding disulfides with good to excellent yields in a phosphate buffer solution under mild reaction conditions.
- Khaledian, Donya,Rostami, Amin,Zarei, Seyed Amir
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- Simple and green method for synthesis of symmetrical dialkyl disulfides and trisulfides from alkyl halides in water; PMOxT as a sulfur donor
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An environmentally new, mild and efficient method has been developed for the synthesis of dialkyl disulfides and dialkyl trisulfides in aqueous conditions by a reaction between alkyl halides (and tosylate) and potassium-5-methyl-1,3,4-oxadiazole-2-thiolate (PMOxT) as a sulfur transfer reagent. The advantages of this method are that it occurs under mild reaction conditions, it is base free, it uses water as the solvent and it occurs in high yields. A variety of dialkyl disulfides and dialkyl trisulfides can be obtained in good to excellent yields up to 98%.
- Soleiman-Beigi, Mohammad,Mohammadi, Fariba
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p. 134 - 141
(2017/03/07)
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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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- Cs2CO3-Catalyzed Aerobic Oxidative Cross-Dehydrogenative Coupling of Thiols with Phosphonates and Arenes
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An efficient Cs2CO3-catalyzed oxidative coupling of thiols with phosphonates and arenes that uses molecular oxygen as the oxidant is described. These reactions provide not only a novel alkali metal salt catalyzed aerobic oxidation, but also an efficient approach to thiophosphates and sulfenylarenes, which are ubiquitously found in pharmaceuticals and pesticides. The reaction proceeds under simple and mild reaction conditions, tolerates a wide range of functional groups, and is applicable to the late-stage synthesis and modification of bioactive molecules.
- Song, Song,Zhang, Yiqun,Yeerlan, Adeli,Zhu, Bencong,Liu, Jianzhong,Jiao, Ning
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p. 2487 - 2491
(2017/02/23)
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- Thieme Chemistry Journals Awardees - Where Are They Now?Molybdenum(V)-Mediated Synthesis of Nonsymmetric Diaryl and Aryl Alkyl Chalcogenides
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Oxidative chalcogenation reaction using molybdenum(V) reagents provides fast access to a wide range of nonsymmetric aryl sulfides and selenides. The established protocol is tolerated by a variety of labile functions, protecting groups, and aromatic heterocycles. In particular, when labile moieties are present, the use of molybdenum(V) reagents provides superior yields compared to other oxidants.
- Franzmann, Peter,Beil, Sebastian B.,Winterscheid, Peter M.,Schollmeyer, Dieter,Waldvogel, Siegfried R.
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supporting information
p. 957 - 961
(2017/05/05)
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- An environmentally benign and selective electrochemical oxidation of sulfides and thiols in a continuous-flow microreactor
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A practical and environmentally benign electrochemical oxidation of thioethers and thiols in a commercially-available continuous-flow microreactor is presented. Water is used as the source of oxygen to enable the oxidation process. The oxidation reaction utilizes the same reagents in all scenarios and the selectivity is solely governed by the applied potential. The procedure exhibits a broad scope and good functional group compatibility providing access to various sulfoxides (15 examples), sulfones (15 examples) and disulfides (6 examples). The use of continuous flow allows the optimal reaction parameters (e.g. residence time, applied voltage) to be rapidly assessed, to avoid mass- and heat-transfer limitations and to scale the electrochemistry.
- Laudadio, Gabriele,Straathof, Natan J. W.,Lanting, Menno D.,Knoops, Benny,Hessel, Volker,No?l, Timothy
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supporting information
p. 4061 - 4066
(2017/09/07)
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- Symmetrical disulfide synthesis via nickel-catalysis using potassium sulfide as sulfur source
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Abstract: An efficient one-pot method for the synthesis of organic disulfides from aryl and alkyl halides and potassium sulfide has been described. K2S acts as an inexpensive and readily available sulfur source. A variety of symmetric diaryl and dialkyl disulfides was prepared in good to excellent yields using NiCl2·6H2O and acetylacetone as the catalytic system. Graphical abstract: [Figure not available: see fulltext.]
- Soleiman-Beigi, Mohammad,Arzehgar, Zeinab
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p. 1759 - 1763
(2016/09/28)
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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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- Organocatalytic visible light induced S-S bond formation for oxidative coupling of thiols to disulfides
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In this work, we developed a visible light induced oxidative coupling of thiols into the corresponding disulfides in a process catalyzed by an inexpensive and non hazardous Rose Bengal dye. Our optimization study revealed that the use of Rose Bengal catal
- Tankam, Theeranon,Poochampa, Kamolrut,Vilaivan, Tirayut,Sukwattanasinitt, Mongkol,Wacharasindhu, Sumrit
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p. 788 - 793
(2016/01/20)
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- A two in one approach: Renewable support and enhanced catalysis for sweetening using chicken feather bound cobalt(II) phthalocyanine under alkali free environment
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Poultry waste chicken feathers, an inexpensive and abundantly available material has been used as a renewable support for immobilizing a cobalt phthalocyanine catalyst. The synthesized heterogeneous cobalt(ii) phthalocyanine catalyst was used for the aerobic oxidation of mercaptans to the corresponding disulfides using ultrasonic irradiation under alkali free conditions. The significantly higher catalytic activity of the heterogeneous catalyst as compared to a homogeneous one can be attributed to the synergistic effect of the support matrix. In addition, the catalyst could easily be recovered and recycled for several runs without loss of activity, which makes the process greener and more cost-effective.
- Chauhan, Deepak K.,Patnam, Padma L.,Ganguly, Sudip K.,Jain, Suman L.
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p. 51983 - 51988
(2016/06/13)
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- Method for preparing disulfide bond containing compound by using TEMPO catalyst through aerobic oxidation
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The invention discloses a method for preparing a disulfide bond containing compound by using a TEMPO catalyst through aerobic oxidation. The method comprises the following steps: adding R-SH, R'-SH and TEMPO into a solvent, and performing heating reflux in an aerobic environment, thereby preparing R-S-S-R'. The method achieves oxidative coupling reaction of thiophenol and mercaptan in the absence of transition metal and is high in yield, good in selectivity and free of over-oxidized product; for aliphatic mercaptan which is relatively poor in activity, the problem of oxidation can be solved by adding copper salt as a promoter, the yield is relatively high, and the reaction is greatly affected by a substitute group; the catalyst is easy to obtain, the reaction condition is gentle, and the method is applicable to large-scale production.
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Paragraph 0065; 0066; 0067; 0068; 0069; 0121-0124
(2016/10/07)
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- Selective synthesis of thioethers in the presence of a transition-metal-free solid Lewis acid
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The synthesis of thioethers starting from alcohols and thiols in the presence of amorphous solid acid catalysts is reported. A silica alumina catalyst with a very low content in alumina gave excellent results in terms of both activity and selectivity also under solvent-free conditions. The reaction rate follows the electron density of the carbinol atom in the substrate alcohol and yields up to 99% and can be obtained for a wide range of substrates under mild reaction conditions.
- Santoro, Federica,Mariani, Matteo,Zaccheria, Federica,Psaro, Rinaldo,Ravasio, Nicoletta
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supporting information
p. 2627 - 2635
(2017/01/09)
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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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- 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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- An efficient one-pot method for the direct synthesis of organic disulfides from aryl/alkyl halides in the presence of CuCl using morpholin-4-ium morpholine-4-carbo-dithioate
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A novel and expedient route is described for the one-pot synthesis of symmetric diaryl (dialkyl) disulfides derivatives via morpholin-4-ium morpholine-4-carbo-dithioate and aryl (alkyl) halides reactions in the presence of CuCl in an aqueous solvent system. Morpholin-4-ium morpholine-4-carbo-dithioate used as new solid, stable and easy handle sulfur Sourcage.
- Soleiman-Beigi, Mohammad,Arzehgar, Zeinab
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p. 395 - 402
(2015/06/22)
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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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p. 340 - 350
(2015/04/27)
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- Metal-Free Photocatalytic Aerobic Oxidation of Thiols to Disulfides in Batch and Continuous-Flow
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Disulfides represent significant molecular and structural features in various biologically active compounds and fine chemicals. Therefore, the development of mild, efficient and sustainable methods to access disulfides is of great importance. Here, we describe the development of a mild metal-free photocatalytic aerobic oxidation of thiols to disulfides using Eosin Y and visible-light irradiation. A continuous flow procedure was developed to accelerate the photocatalytic process, enabling the preparation of disulfides with high purity in a timeframe of minutes. The mildness and applicability of our method was exemplified by the flow synthesis of the cyclic peptide hormone, oxytocin, requiring only a 200s reaction time and an efficient one-pot batch protocol for the preparation of the therapeutic thiuram disulfide, disulfiram.
- Talla, Ali,Driessen, Brian,Straathof, Natan J. W.,Milroy, Lech-Gustav,Brunsveld, Luc,Hessel, Volker,No?l, Timothy
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supporting information
p. 2180 - 2186
(2015/07/27)
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- Haloacid/dimethyl sulfoxide-catalyzed synthesis of symmetrical disulfides by oxidation of thiols
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A novel method is developed for the oxidation of thiols to the corresponding disulfides using 20 mol % haloacid (HBr or HI) in combination with dimethyl sulfoxide. A tentative mechanism is proposed for the oxidation. In addition to the advantages of cost-effectiveness, simple processes, and broad functional group tolerance, the exclusive formation of disulfides is the principle reward of this methodology while compared to known methods that further oxidize disulfides to S-oxides and other byproducts.
- Natarajan, Palani,Sharma, Himani,Kaur, Mandeep,Sharma, Pooja
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supporting information
p. 5578 - 5582
(2015/09/21)
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- Magnetic Fe3O4@MgAl-LDH composite grafted with cobalt phthalocyanine as an efficient heterogeneous catalyst for the oxidation of mercaptans
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Magnetically separable layered double hydroxide MgAl-LDH@Fe3O4 composite supported cobalt phthalocyanine catalyst was synthesized and used for the aerobic oxidation of mercaptans to corresponding disulfides under alkali free conditions. The catalyst exhibited excellent activity for the oxidation of mercaptans using molecular oxygen as an oxidant which can be effectively recovered by using an external magnetic field. In addition, the covalent immobilization of cobalt phthalocyanine to MgAl-LDH@Fe3O4 support prevents the leaching of the catalyst and improves its activity and stability.
- Kumar, Pawan,Gill, Kareena,Kumar, Sunil,Ganguly, Sudip K.,Jain, Suman L.
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- A mild and efficient method for the conversion of aldehydes into nitriles and thiols into disulfides using an ionic liquid oxidant
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A simple, mild and high yielding method for the conversion of various aldehydes to nitriles has been developed using an ionic liquid reagent, hexamethylene bis(N-methylimidazolium) bis(dichloroiodate) (HMBMIBDCI), in combination with aqueous ammonia in CH3CN at room temperature. Moreover, the treatment of aromatic and aliphatic thiols with HMBMIBDCI resulted in the corresponding disulfides in solvent-free condition at room temperature.
- Hosseinzadeh, Rahman,Golchoubian, Hamid,Nouzarian, Mahboobe
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p. 4713 - 4725
(2015/06/30)
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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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- Equilibrium shift induced by chiral nanoparticle precipitation in rhodium-catalyzed disulfide exchange reaction
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Chiral silica (P)-nanoparticles grafted with (P)-helicene recognize the molecular structure of a chiral diol disulfide in the presence of monool disulfide and dibutyl disulfide. The (P)-nanoparticles selectively adsorb the diol disulfide, aggregate, and precipitate from solution. Under rhodium-catalyzed equilibrium among three disulfides, the diol disulfide is removed from solution by precipitation, which induces an equilibrium shift in the solution. By conducting the precipitation experiment twice, we obtained the diol disulfide in 37% yield from a statistical 1:2:1 equilibrium mixture of three disulfides. The method is applied to a racemic monool disulfide, and an optically active diol disulfide is obtained via kinetic resolution and equilibrium shift.
- Miyagawa, Masamichi,Arisawa, Mieko,Yamaguchi, Masahiko
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p. 4920 - 4926
(2015/06/23)
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- Deep eutectic mixture catalysed the synthesis of disulfides using Bunte salts as thiol surrogates
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Bunte salts, easily prepared from odourless sodium thiosulfates and various alkyl and aryl halides, acted as thiol surrogates for preparation of disulfides in the presence of hydrogen peroxide and a Bronsted-acidic deep eutectic mixture. The reaction proceeded smoothly to give the corresponding disulfide products in moderate to good yields, leaving odourless sodium bisulfite and water as the by-products. Moreover, this catalytic system could be readily recovered and reused several times without significant loss in activity.
- Zhou, Yongsheng
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p. 332 - 335
(2015/08/18)
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- Direct synthesis of disulfides from alkyl halides using thiourea and CCl4 in glycerol
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Abstract Dialkyl disulfides were obtained on the basis of the reaction of alkyl halides and thiourea in the presence of CCl4 and Et3N. This procedure enables the odorless and one-pot synthesis of disulfides by employing cheap, easy-to-handle and readily available reagents and substrates in wet glycerol.
- Abbasi, Mohammad,Khalili, Dariush
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p. 1425 - 1430
(2015/06/22)
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- Hypervalent iodine(III)-promoted metal-free S-H activation: An approach for the construction of S-S, S-N, and S-C bonds
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The activation of the sulfur atom of thiols with (diacetoxyiodo)benzene (DIB) has been explored in the preparation of symmetrical disulfides and sulfenamides. Disulfides can be produced in excellent yields (75-95%) upon treatment of thiols with DIB. The reaction was complete in less than five minutes at room temperature. Aliphatic, aromatic, and heteroaromatic thiols are compatible with this transformation. Moreover, heteroaromatic disulfides obtained from heteroaromatic thiols further reacted with a nucleophilic amine in the presence of a base to provide the corresponding sulfenamides in fair to good yields (43-90%) in a one-pot fashion. The methodology was successfully extended to indole as a representative electron-rich aromatic compound, which allowed successful construction of a S-C bond in one pot. The key benefits of this reaction include lower toxicity, low cost of DIB reagent, and mild reaction conditions (room temperature, undried solvents and open flask).
- Rattanangkool, Eakkaphon,Krailat, Watanya,Vilaivan, Tirayut,Phuwapraisirisan, Preecha,Sukwattanasinitt, Mongkol,Wacharasindhu, Sumrit
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p. 4795 - 4804
(2014/08/05)
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- Simple conversion of thiols to disulfides in EtOH under ambient aerobic conditions without using any catalyst or additive
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EtOH was found to be an excellent medium for the aerobic S-S coupling reactions of various alkyl and aryl thiols. A series of useful disulfides RSSR have been synthesised in good to excellent yields without using any additional catalyst, oxidant or additive. Moreover, most products could be obtained by simply removing the solvent after completion of the reaction. Satisfactory results were obtained for both mg- and g-scale reactions.
- Wang, Hang,Huang, Guojun,Sun, Yang,Liu, Yunyun
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- Design, synthesis, and biological evaluation of largazole derivatives: Alteration of the zinc-binding domain
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A new series of largazole analogues in which the side chain was replaced with disulfide groups were synthesized, and their biological activities were evaluated. Compound 8 bearing an octyl moiety showed much better selectivity for HDAC1 over HDAC7 than largazole (320-fold). Structure-activity relationships suggested that the length in the disulfide chain of largazole is important for the selectivity toward HDAC1 over HDAC7.
- Su, Jinyue,Qiu, Yatao,Ma, Kun,Yao, Yiwu,Wang, Zhen,Li, Xianling,Zhang, Dayong,Tu, Zhengchao,Jiang, Sheng
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p. 7763 - 7769
(2014/12/10)
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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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- Rapid and convenient method for the synthesis of symmetrical disulfides
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We present here the results on the use of 1,3,5-triazo-2,4,6- triphosphorine-2,2,4,4,6,6-hexachloride as an efficient promoter in the conversion of thiols to the corresponding symmetrical disulfides under solvent-free conditions. Aromatic thiols bearing electron donating and electron withdrawing groups, heteroaromatic, and alkyl thiols reacted efficiently to afford excellent yields of disulfides in short reaction times after easy work-up. Different functional groups including carboxyl, methoxy, methylthio, and halogen are tolerated. Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures and tables.
- Bahrami, Kiumars,Khodaei, Mohammad M.,Shakibaian, Vida,Targhan, Homa
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p. 981 - 988
(2013/09/02)
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- (NH 4) 6Mo 7O 34·4H 2O as an efficient, selective, and reusable catalyst for the oxidation of thiols to disulfides using potassium bromate
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Ammonium molybdate, (NH 4) 6Mo 7O 34·4H 2O, is found to be an efficient and selective catalyst for the oxidation of thiols to corresponding disulfides using potassium bromate in aqueous acetonitrile as the solvent. Among various solvents tested, CH3CN/H2O showed better results in terms of the reaction yield and rate. In the absence of (NH4)6Mo 7O24·4H2O, the oxidation reaction is not selective for the formation of disulfides. The catalyst can be easily recovered after completion of the reaction and reused without any significant loss of its activity. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]
- Bayraq, Samad Shoghpour,Nikseresht, Ahmad,Khosravi, Iman
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supporting information
p. 1236 - 1243
(2013/09/23)
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- Bio-based green solvent mediated disulfide synthesis via thiol couplings free of catalyst and additive
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The bio-based green solvent ethyl lactate has been found to be a particularly efficient medium for oxidative coupling reactions of thiols yielding a broad array of disulfides. As a green solvent, ethyl lactate has shown an interesting promotion effect on the transformation by mediating corresponding reactions with high efficiency without using any catalyst or additive. The Royal Society of Chemistry 2013.
- Liu, Yunyun,Wang, Hang,Wang, Chunping,Wan, Jie-Ping,Wen, Chengping
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p. 21369 - 21372
(2013/11/06)
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- An efficient metal-free synthesis of organic disulfides from thiocyanates using poly-ionic resin hydroxide in aqueous medium
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An efficient and metal-free method is described for the preparation of organic disulfides from alkyl and acyl methyl thiocyanates in the presence of poly-ionic resin hydroxide in aqueous medium. Further extension of this protocol has been tested using two different organyl thiocyanates to prepare unsymmetrical disulfides.
- Sengupta, Debasish,Basu, Basudeb
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supporting information
p. 2277 - 2281
(2013/05/08)
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- One-pot palladium-catalyzed borrowing hydrogen synthesis of thioethers
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Palladium on magnesium oxide is able to allow a one-pot reaction to synthesize thioethers from thiols and aldehydes formed in situ from the respective alcohol by means of a borrowing hydrogen method. The reaction is initiated by dehydrogenation of the alcohol to give a palladium hydride intermediate and an aldehyde. The latter reacts with a thiol involving most probably the intermediacy of a thionium ion RCHi£S+R, which can be reduced in situ by the metal hydride to afford thioethers. Lending support: Palladium nanoparticles on MgO catalyze the synthesis of thioethers from thiols and aldehydes formed in situ from alcohols by means of the borrowing hydrogen method (see scheme). Dehydrogenation of the alcohol gives a palladium hydride intermediate and an aldehyde. The latter reacts with a thiol through a thionium ion, which is reduced by the metal hydride to afford thioethers.
- Corma, Avelino,Navas, Javier,Rodenas, Tania,Sabater, Maria J.
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p. 17464 - 17471
(2014/01/06)
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- A simple and practical method for the oxidation of thiols to disulfides at mild conditions without solvents
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A green, straightforward, and novel method for the oxidation of thiols to the corresponding disulfides is reported using hydrogen peroxide catalyzed by tetrabutylammonium iodide (TBAI) without solvents at room temperature. The corresponding disulfides were obtained with excellent yields and short reaction times. Copyright
- He, Ying,Hang, Dongliang,Lu, Ming
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experimental part
p. 1118 - 1124
(2012/08/14)
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- Microwave assisted oxidative coupling of thiols to symmetrical disulfides with tripropylammonium fluorochromate(VI) (TPAFC)
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Tripropylammonium fluorochromate(VI) (TPAFC) is an efficient and novel reagent, which can be prepared easily and oxidizes thiols to the corresponding disulfides, quickly. The reactions are performed cleanly and are controlled to stop at the disulfide stage, without over-oxidation or side products. Coupling of thiols to their corresponding disulfides, was studied in solution at room temperature and under conditions using a minimal amount of solvent under microwave irradiation. The easy procedure, simple work-up, short reaction times, and excellent yields are other advantages of this reagent.
- Mohammadi, Mohammad Kazem,Ghammamy, Shahriare
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experimental part
p. 139 - 144
(2012/04/23)
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- Modified polyacrylamide-supported chlorochromate as a new polymeric oxidizing agent
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Modified polyacrylamide-supported chlorochromate was synthesized and used as a versatile and efficient oxidizing agent for the oxidation of various organic compounds, such as hydroxyl compounds, silylethers, oximes, thiols, and others. Over oxidation of the products (aldehydes to carboxylic acids) was not observed with this oxidizing agent. The oxidant was insoluble in the oxidation media and the chromium(VI) ions remained firmly bound to the insoluble polymeric support after the oxidation reaction. The mild reaction condition, easy work-up, short reaction times, regenerability of the reagent and its easy preparation and handling are among the advantages of this new polymeric chlorochromate reagent. 2012 Copyright (CC) SCS.
- Tamami, Bahman,Heiran, Roghayeh,Montazer, Elham Riazi
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p. 685 - 697
(2012/10/29)
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- Heteroaromatic azo compounds as efficient and recyclable reagents for direct conversion of aliphatic alcohols into symmetrical disulfides
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4,4′-Azopyridine 1a and 5,5′-dimethyl-3,3′-azoisooxazole 1e are used for the efficient, direct, and selective conversion of aliphatic alcohols into their corresponding disulfides in high yields under Mitsunobu conditions in combination with PPh3/sub
- Iranpoor, Nasser,Firouzabadi, Habib,Khalili, Dariush
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p. 6913 - 6915
(2013/01/15)
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