- Reaction of organic disulfides with cobalt-centered metal radicals. Use of the E- and C-based dual-parameter substituent model and quantitative solvent effect analyses to compare outer-sphere and inner-sphere electron- transfer processes
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Treatment of isolable, paramagnetic Cp2Ta(μ-CH2)2CoCp (1, Cp = η5- C5H5) with aromatic disulfides RSSR affords diamagnetic monothiolate complexes Cp2Ta(μ-CH2)2Co(SR)Cp in quantitative yield. The structure of Cp2Ta(μ-CH2)2Co(SC6H3(CH3)2)Cp (2a) has been characterized by X-ray crystallography. The mechanism of this disulfide S-S bond cleavage reaction has been probed using kinetic, substituent effect, and solvent effect techniques. A Hammett σ/ρ substituent constant analysis yields a nonlinear correlation. In contrast, application of the E- and C-based dual-parameter substituent model gives a good fit of the data and demonstrates that the reaction is sensitive to both the electrostatic and the covalent characteristics of the entering disulfide. All substituents examined (excluding p-(trifluoromethyl)phenyl) exhibited a solvent effect consistent with a modest amount of charge separation in the transition state. The reaction of 1 with the strongly electron withdrawing substituted bis[p- (trifluoromethyl)phenyl] disulfide is much more sensitive to solvent polarity changes. As a comparison system expected to proceed via a limiting outer- sphere electron-transfer mechanism, the reaction of aromatic disulfides with the 19-electron complex cobaltocene (CoCp2, 3), which leads to salts [CoCp2][SR] (4), was investigated using methods parallel to those employed in the study of Ta/Co complex 1. In the cobaltocene system, the kinetic, solvent effect, and substituent effect data showed that the reaction is especially sensitive to the electrostatic character of the disulfide and relatively insensitive to its Covalent character and steric bulk. The comparison of cobaltocene with Ta/CO complex 1 shows that the latter reacts with most diaryl disulfides (perhaps with the exception of p-CF3 compound 2f, which may be a borderline case) via a transition state with substantially more covalent character, and correspondingly less charge separation. than that involved in the outer-sphere reactions of Cp2Co.
- Aubart, Mark A.,Bergman, Robert G.
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- Indolylarylsulfones carrying a heterocyclic tail as very potent and broad spectrum HIV-1 non-nucleoside reverse transcriptase inhibitors
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We synthesized new indolylarylsulfone (IAS) derivatives carrying a heterocyclic tail at the indole-2-carboxamide nitrogen as potential anti-HIV/AIDS agents. Several new IASs yielded EC50 values 1.0 nM against HIV-1 WT and mutant strains in MT-4 cells. The (R)-11 enantiomer proved to be exceptionally potent against the whole viral panel; in the reverse transcriptase (RT) screening assay, it was remarkably superior to NVP and EFV and comparable to ETV. The binding poses were consistent with the one previously described for the IAS non-nucleoside reverse transcriptase inhibitors. Docking studies showed that the methyl group of (R)-11 points toward the cleft created by the K103N mutation, different from the corresponding group of (S)-11. By calculating the solvent-accessible surface, we observed that the exposed area of RT in complex with (S)-11 was larger than the area of the (R)-11 complex. Compounds 6 and 16 and enantiomer (R)-11 represent novel robust lead compounds of the IAS class.
- Famiglini, Valeria,La Regina, Giuseppe,Coluccia, Antonio,Pelliccia, Sveva,Brancale, Andrea,Maga, Giovanni,Crespan, Emmanuele,Badia, Roger,Riveira-Mu?oz, Eva,Esté, José A.,Ferretti, Rosella,Cirilli, Roberto,Zamperini, Claudio,Botta, Maurizio,Schols, Dominique,Limongelli, Vittorio,Agostino, Bruno,Novellino, Ettore,Silvestri, Romano
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- Transformation of arylboronic acids with sodium thiosulfate into organodisulfides catalyzed by a recyclable polyoxometalate-based Cr(iii) catalyst
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Organo disulfides represent an abundant class of compounds in chemical biology, pharmaceutical fields, and industry. They are traditionally synthesized by the oxidation of mercaptan in the presence of an organic ligand supported metal catalyst or toxic oxidants under harsh conditions. Here, we disclose a highly-efficient pathway in which disulfide is synthesized by organic boric acid and Na2S2O3 using the catalyst (NH4)3[CrMo6O18(OH)6], demonstrating a high activity and excellent selectivity. Various boric acid derivatives have been successfully transformed into the corresponding disulfides. Mechanistic insights have been furnished based on the observation of intermediate and control experiments.
- Chang, Yalin,Li, Huiyi,Tao, Chaofu,Wang, Aiping,Wei, Yongge,Xie, Ya,Yu, Han,Yu, Shunming
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supporting information
p. 6059 - 6064
(2021/08/23)
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- Metal-free chalcogenation of cycloketone oxime esters with dichalcogenides
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We report the metal-free chalcogenation of cycloketone oxime esters with dichalcogenides via a radical process. Because of the metal-free condition and use of readily accessible dichalcogenides, this method is an effective and green strategy for the synthesis of chalcogen-substituted butyronitrile.
- Ji, Liangshuo,Qiao, Jiamin,Liu, Junjie,Tian, Miaomiao,Lu, Kui,Zhao, Xia
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supporting information
(2021/06/15)
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- Sequential C-H activation enabled expedient delivery of polyfunctional arenes
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Modular construction of polyfunctional arenes from abundant feedstocks stands as an unremitting pursue in synthetic chemistry, accelerating the discovery of drugs and materials. Herein, using the multiple C-H activation strategy with versatile imidate esters, the expedient delivery of molecular libraries of densely functionalized sulfur-containing arenes was achieved, which enabled the concise construction of biologically active molecules, such as Bipenamol.
- Cai, Xiaoqing,Chen, Qian,Chen, Xiaojian,Gao, Yang,Huo, Yanping,Li, Xianwei,Ouyang, Wensen,Rao, Jianhang,Wang, Jie
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supporting information
p. 8075 - 8078
(2021/08/20)
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- Chemoselective synthesis of diaryl disulfides via a visible light-mediated coupling of arenediazonium tetrafluoroborates and CS2
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A highly efficient and chemoselective method for the synthesis of diaryl disulfides is developed via a visible light-promoted coupling of readily accessible arenediazonium tetrafluoroborates and CS2. This practical and convenient protocol provides a direct pathway for the assembly of a series of disulfides in an environmentally friendly manner with good to excellent yields.
- Leng, Jing,Wang, Shi-Meng,Qin, Hua-Li
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supporting information
p. 903 - 909
(2017/06/23)
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- Diacetoxyiodobenzene mediated oxidative transformation of thione to disulfides
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We have developed an efficient oxidative transformation of thione to disulfides using diacetoxyiodobenzene (DIB) in acetonitrile at room temperature. This strategy is suited for oxidation of thiols to disulfide also. The present oxidation protocol is mild reaction condition, column free, and a new route for disulfide formation.
- Singh, Sarangthem Joychandra,Devi, Nepram Sushuma
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supporting information
p. 5941 - 5943
(2016/12/07)
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- Silica: An efficient catalyst for one-pot regioselective synthesis of dithioethers
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The development of a silica-promoted highly selective synthesis of 1,2 or 1,3-dithioethers via solvent-free one-pot tandem reactions of an allyl bromide with excess thiol at room temperature is described. The choice of silica gel, either pre-calcined or moistened with water, exhibited notable regioselectivity in the formation of dithioethers. Plausible mechanistic routes were explored and postulated.
- Kundu, Samir,Roy, Babli,Basu, Basudeb
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- Aerobic oxidation of thiols to disulfides under ball-milling in the absence of any catalyst, solvent, or base
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An efficient aerobic chemoselective oxidation of thiols to disulfides has been achieved under ball-milling over neutral aluminium oxide (grinding auxiliary) in the absence of any catalyst, co-oxidant, solvent, or base. A wide variety of functionalized diaryl, diheteroaryl and dialkyl disulfides have been obtained in high yields. The Royal Society of Chemistry 2013.
- Chatterjee, Tanmay,Ranu, Brindaban C.
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p. 10680 - 10686
(2013/09/02)
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- CuI-nanoparticles-catalyzed selective synthesis of phenols, anilines, and thiophenols from aryl halides in aqueous solution
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CuI-nanoparticles-catalyzed selective synthesis of phenols, anilines, and thiophenols from aryl halides was developed in the absence of both ligands and organic solvents. Anilines were formed selectively with ammonia competing with hydroxylation and thiophenols were generated selectively with sulfur powder after subsequent reduction competing with hydroxylation and amination.
- Xu, Hua-Jian,Liang, Yu-Feng,Cai, Zhen-Ya,Qi, Hong-Xia,Yang, Chun-Yan,Feng, Yi-Si
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supporting information; experimental part
p. 2296 - 2300
(2011/06/17)
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- Synthesis of diaryl disulfides via the reductive coupling of arylsulfonyl chlorides
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A facile synthesis of diaryl disulfides from arylsulfonyl chlorides in the presence of triphenylphosphine has been developed.
- Kabalka, George W.,Reddy, Marepally Srinivasa,Yao, Min-Liang
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scheme or table
p. 7340 - 7342
(2010/03/01)
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- Electrochemical transformation of diazonium salts into diaryl disulfides
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Electrolyses of aryldiazonium tetrafluoroborates in CS2/EtOH and Bu4NClO4, as the solvent-supporting electrolyte system, led to the corresponding diaryl disulfides in good yields.
- Barba, Fructuoso,Ranz, Fernando,Batanero, Belen
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experimental part
p. 6798 - 6799
(2010/04/27)
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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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- CuCl-catalyzed cleavage of S-triphenylmethyl thioether: a new detritylation method for thio group
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A new method for the deprotection of trityl thioethers using CuCl as the catalyst under ultrasonic conditions is described.
- Ma, Ming,Zhang, Xiu,Peng, Lingling,Wang, Jianbo
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p. 1095 - 1097
(2008/01/27)
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- Oxidation of thiols to bisulfides using silica chloride as a heterogeneous catalyst
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Silica chloride is used as a selective and effective heterogeneous catalyst for the rapid conversion of thiols to disulfides with quantitative yields in a very short period of time. Copyright
- Sathe, Manisha,Ghorpade, Ramarao,Kaushik, Mahabir Parshad
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p. 1048 - 1049
(2007/10/03)
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- A New Type of Reductive Cleavage of Disulfide in Quadruply ortho-Substituted Diphenyl Disulfide by Neighboring Thiolate Anion
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The reaction of bisdisulfide with thiourea or sodium sulfide showed an unusual reductive cleavage of disulfide linkage with elimination of bromine by neighboring-group participation of the generated thiolate anion.Its reaction gave the structurally intriguing thiols which indicated the facile anodic oxidation.
- Fujihara, Hisashi,Chiu, Jer-Jye,Furukawa, Naomichi
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p. 699 - 701
(2007/10/02)
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- The co-oxidation reaction of isoprene and some aromatic thiols
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The co-oxidation reaction between isoprene, some aromatic thiols and molecular oxygen is described.The product distribution, in relation to the nature of the aromatic thiol used, is examined.Steric and electronic factors are discussed.
- Laan, R. van der,Moolenaar, M.J.,Koning, H. de,Huisman, H.O.
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p. 220 - 225
(2007/10/02)
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- A MILD REDUCTION OF ARENESULFONIC ACID AND ITS DERIVATIVES WITH DIPHOSPHOROUS TETRAIODIDE
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When treated with diphosphorous tetraiodide in boiling acetonitrile or under neat conditions, arenesulfonic acids, their salts, chlorides, esters, and amides are reduced to aryl disulfides in good to moderate yields.
- Suzuki, Hitomi,Tani, Hiroyuki,Osuka, Atsuhiro
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p. 139 - 142
(2007/10/02)
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- Chemistry of Sulfenic Acids. 3. Studies of Sterically Hindered Sulfenic Acids Using Flash Vacuum Pyrolysis
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Flash vacuum pyrolysis (FVP) of sulfoxides containing β-hydrogen atoms affords sulfenic acids (RSOH) in good concentration under conditions where they are stable.The application of this technique to the synthesis and study of sterically hindered sulfenic acids 12a-e is described.The principal or primary reaction of simple sulfenic acids prepared in this manner is dehydration to thiosulfinates 13 (eq 1).Steric inhibition to dehydration (eq 1) appears to only be of importance for 2-methyl-2-propanesulfenic acid (12a) which was trapped in good yield with methyl propiolate to afford 16a. 2,4,6-Tri-tert-butylbenzenesulfenic acid (12e) appears to be destabilized as a consequence of interaction between the SOH and adjacent tert-butyl groups.In the pyrolysis section of the apparatus, 12e decomposes to phenol 21 and aryl radical 22, which reacts further.Thermolysis of sulfoxides generates the sulfenic acids 12a-e in very low concentration at any one time.The products of sulfenic acids generated in this way result from secondary reactions of the corresponding thiosulfinates.
- Davis, Franklin A.,Jenkins, Robert H.,Rizvi, Syed Q. A.,Yocklovich, Steven G.
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p. 3467 - 3474
(2007/10/02)
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