- H5[PMo10V2O40] as a green, reusable, and highly efficient catalyst for the oxidation of dithiols in intermolecular reactions using permanganate as an oxidizing reagent
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[H5PV2Mo10O40] catalyzed oxidation of dithiols to related cyclic disulfides. Potassium permanganate as an oxidizing reagent under mild conditions was carried out in this reaction. This system provides an efficient, convenient, and practical method for the syntheses of cyclic disulfides. In this work, the comparisons among the Keggin and Dawson ions are addressed in term of relative stability hardness and acidity. Copyright Taylor & Francis Group, LLC.
- Harutyunyan,Rezvani,Heravi, Majid M.
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Read Online
- Preparation method of rubber aid 1,6-bis(N,N-dibenzyl carbamyl disulfide) hexane
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The invention provides a preparation method of a rubber aid 1,6-bis(N,N-dibenzyl carbamyl disulfide) hexane. According to the method, 1,6-dimercaptohexane is used as a raw material and reacts with hydrogen peroxide to form 1,2-dithiocyclooctane, then the 1,2-dithiocyclooctane reacts with chlorine to form 1,6-secondary sulfonyl chloride octane, and the 1,6-secondary sulfonyl chloride octane reactswith dibenzyl dithiocarbamate to form a final product. The synthesis process is simple and easy to operate, the reaction time is shortened, and the production efficiency and the yield are improved. According to the method, no toxic and harmful substance formaldehyde is used, no 1,6-dithiosulfo hexane disodium salt hydrate is used, a large amount of organic wastewater containing inorganic salt is reduced, the used solvent can be reused after simple treatment, and the process is clean and environmentally friendly.
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Paragraph 0022; 0025; 0028; 0031; 0034
(2020/06/09)
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- [FeFe]-Hydrogenase H-Cluster Mimics with Various -S(CH2)nS- Linker Lengths (n = 2-8): A Systematic Study
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The effect of the nature of the dithiolato ligand on the physical and electrochemical properties of synthetic H-cluster mimics of the [FeFe]-hydrogenase is still of significant concern. In this report we describe the cyclization of various alkanedithiols to afford cyclic disulfide, tetrasulfide, and hexasulfide compounds. The latter compounds were used as proligands for the synthesis of a series of [FeFe]-hydrogenase H-cluster mimics having the general formulas [Fe2(CO)6{μ-S(CH2)nS}] (n = 4-8), [Fe2(CO)6{μ-S(CH2)nS}]2 (n = 6-8), and [Fe2(CO)6{(μ-S(CH2)nS)2}] (n = 6-8). The resulting complexes were characterized by 1H and 13C{1H} NMR and IR spectroscopic techniques, mass spectrometry, and elemental analysis as well as X-ray analysis. The purpose of this research was to study the influence of the systematic increase of n from 2 to 7 on the redox potentials of the models and the catalytic ability in the presence of acetic acid (AcOH) by applying cyclic voltammetry.
- Abul-Futouh, Hassan,Almazahreh, Laith R.,Harb, Mohammad Kamal,G?rls, Helmar,El-Khateeb, Mohammad,Weigand, Wolfgang
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p. 10437 - 10451
(2017/09/12)
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- Comparison of cyclic and polymeric disulfides as catalysts for the regioselective chlorination of phenols
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Two cyclic and two polymeric disulfides have been synthesized and established to be useful catalysts for the chlorination of m-xylenol, o-cresol, m-cresol and phenol using freshly distilled sulfuryl chloride in the presence of aluminum or ferric chloride as a co-catalyst at room temperature. The yields of p-isomers and para/ortho ratios were higher compared to cases where no catalyst was used with most catalysts for most phenols even when a very low concentration of disulfide was used.
- Smith, Keith,Al-Zuhairi, Ali J.,El-Hiti, Gamal A.,Alshammari, Mohammed B.
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- The synthesis of polymeric sulfides by reaction of dihaloalkanes with sodium sulfide
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Several poly(alkylene sulfide)s have been synthesized in excellent yields from reactions of α,ω-dibromo- and/or α,ω- dichloroalkanes with sodium sulfide nonahydrate under reflux conditions. The procedure is general, simple and convenient for the production of various poly(alkylene sulfide)s and the way reaction parameters influence the properties of the polymers formed has been examined.
- Smith, Keith,El-Hiti, Gamal A.,Al-Zuhairi, Ali J.
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experimental part
p. 521 - 531
(2012/04/23)
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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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- Chlorination of aromatic compounds and catalysts therefor
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A process for the chlorination of an aromatic compound of the following formula (A) : wherein RAis H or C1to C12alkyl, cycloalkyl, aryl, alkaryl, aralkyl or carboxyalkyl, the or each RBindependently is selected from H, C1-C4alkyl (especially methyl), C1-C4haloalkyl or polyhaloalkyl, e.g. C1-C4perfluoroalkyl, C1-C4alkoxy, C5-C12aryl (e.g. phenyl), alkaryl or aralkyl, or halogen, n is an integer which is 0, 1 or 2, and the or each RB, if present, may independently be attached at the ortho or the meta position (preferably at the meta-position), which process comprises reacting (preferably in homogeneous liquid phase below 35°C) the aromatic compound (which is preferably phenol) with a chlorinating agent (preferably sulphuryl chloride) in the presence of a sulphur-containing catalyst, optionally also in the presence of a Lewis acid co-catalyst, characterised in that the sulphur-containing catalyst is a compound according to the following formula (I) or formula (II) : in which: each of X1, X2, and X3is independently selected from the group consisting of: S, SO, SO2; R1is selected from the group consisting of: optionally substituted straight or branched chain alkyl or alkanediyl having from 2 to 20 carbon atoms, optionally substituted straight or branched chain alkaryl or aralkyl having from 5 to 20 carbon atoms, and optionally substituted aryl having from 5 to 20 carbon atoms; R2is an optionally substituted straight or branched chain alkyl or alkanediyl group having from 1 to 20 carbon atoms; R3and R4are each independently selected from the group consisting of: H, optionally substituted straight or branched chain alkyl or alkanediyl having from 1 to 20 carbon atoms, optionally substituted straight or branched chain alkaryl or aralkyl having from 5 to 20 carbon atoms, and optionally substituted aryl having from 5 to 20 carbon atoms; R5is an optionally substituted straight or branched chain alkylene, arylene, alkarylene or arylalkylene group having from 1 to 20 carbon atoms; wherein in the above definitions of R1, R2, R3, R4and R5the optional substituents may be independently selected from the following: halogen (e.g. F, Cl), hydroxy, amino, cyano, nitro, C1-C4alkyl, C1-C4haloalkyl e.g. C1-C4perfluoroalkyl, C1-C4alkoxy, C1-C4alkoxycarbonyl.
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- Highly Selective Sulfur Transfer Reaction in the Solid State
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Benzyltriethylammonium tetrathiomolybdate 1 reacts readily with benzyl halides, alkyl iodides and acyl halides in the solid state to give the corresponding disulfides in good yields and with remarkable selectivity.
- Ramesha, A. R.,Chandresekaran, Srinivasan
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p. 767 - 768
(2007/10/02)
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- The macrocyclization reaction of terminal dibromoalkanes with sulfide on alumina. The use of a solid support as an alternative to the high dilution technique
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The reaction of a series of terminal dibromoalkanes with S-2 on Al2O3 has been examined. The use of a solid support for the macrocyclization represents a viable alternate procedure to the more traditional high dilution technique in solution. The cyclization also occur with thioacetamide on unactivated alumina.
- Tan,Pagni,Kabalka,Hillmeyer,Woosley
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p. 7709 - 7712
(2007/10/02)
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- A Reagent for Reduction of Disulfide Bonds in Proteins That Reduces Disulfide Bonds Faster Than Does Dithiothreitol
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We have synthesized a new reagent - N,N'-dimethyl-N,N'-bis(mercaptoacetyl)hydrazine (DMH) - for the reduction of disulfide bonds in proteins.DMH reduces disulfide bonds 7 times faster than does dithiothreitol (DTT) in water at pH 7.DMH reduces mixed disulfides of cysteine proteases (papain and ficin) especially rapidly (30 times faster than DTT).DMH (ε0 = -0.300 V) reduces noncyclic disulfides completely, although it is less strongly reducing than DTT (ε0 = -0.356 V).
- Singh, Rajeeva,Whitesides, George M.
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p. 2332 - 2337
(2007/10/02)
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- ACTIVATION AND SYNTHETIC APPLICATION OF THIOSTANNANES. EFFICIENT CONVERSION OF THIOL ACETATES INTO DISULFIDES
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Thiostannanes are obtained by treating alkoxystannanes with thiol acetates.Coupled with this reaction, the thiostannane methodology enables one-pot synthesis of disulfides from thiol acetate.
- Sato, Tsuneo,Otera, Junzo,Nozaki, Hitosi
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p. 3595 - 3596
(2007/10/02)
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- ACTIVATION AND SYNTHETIC APPLICATIONS OF THIOSTANNANES. EFFICIENT CONVERSION OF THIOLS INTO DISULFIDES
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Various kinds of thiols are converted into the corresponding disulfides under mild conditions with the aid of alkoxystannane-ferric chloride.
- Sato, Tsuneo,Otera, Junzo,Nozaki, Hitosi
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p. 3591 - 3594
(2007/10/02)
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- CHARACTERIZATION AND STABILITY OF CYCLIC DISULFIDES AND CYCLIC DIMERIC BIS(DISULFIDES)
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This paper describes the preparation of cyclic bis(disulfide) dimers derived from trans-2-butene-1,4-dithiol and cis-1,2-cyclohexane dithiol and the cyclic tris(disulfide) dimer of 1,3,5-tris(mercaptomethyl)benzene by high dilution oxidation of the thiols with iodine.The stability toward ring-opening polymerization of these three new cyclic disulfides and of nine previously reported cyclic disulfides was tested by heating the disulfide with a catalytic amount of sodium methanethiolate.None of the cyclic bis(disulfides) were stable with respect to polymerization under these conditions.The results of these experiments, together with literature reports concerning the stability of similar disulfides, indicate that few simple alkyl disulfides are thermodynamically stable in cyclic form.
- Houk, Janette,Whitesides, George M.
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- HIGH YIELD PREPARATION OF CYCLIC DISULFIDES USING ALKYLTIN THIOLATES
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Cyclic disulfides with ring sizes ranging from 5 to 10 are formed by iodination or bromination of alkyltin thiolates without the need of high dilution.
- Harpp, David N.,Bodzay, Steve J.,Aida, T.,Chan, T. H.
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p. 441 - 444
(2007/10/02)
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- Conversion of Thiols into Disulfides with Diethyl Bromomalonate
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Reaction of aliphatic, aromatic and heterocyclic thiols (2 and 5a-h) with diethyl bromomalonate (1a) gave the corresponding symmetrical disulfides (3 and 6a-h) in high yields.In the case of L-cysteine (5i), glutathione (5j) or thiamine (5k), the reaction also gave L-cystine (6i), oxidized glutathione (6j) or thiamine disulfide (6k) in high yields regardless of the presence of other functional groups.Dithiols (11) were converted into cyclic disulfides (12) by this method.In particular, N-(2-mercapto-2-methylpropionyl)-L-cysteine (9) was converted into (4R)-tetrahydro-7,7-dimethyl-6-oxo-3H-1,2,5-dithiazepine-4-carboxylic acid (10) (obtained in poor yields by general oxidation methods) in good yields.The intermediate in the reaction was considered to be sulfenyl bromide (8).Keywords-diethyl bromomalonate; thiol; dithiol; disulfide; cyclic disulfide; thiol oxidation; disulfide formation; N-(2-mercapto-2-methylpropionyl)-L-cysteine; (4R)-tetrahydro-7,7-dimethyl-6-oxo-3H-1,2,5-dithiazepine-4-carboxylic acid
- Kato, Eishin,Oya, Masayuki,Iso, Tadashi,Iwao, Jun-ichi
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p. 486 - 495
(2007/10/02)
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