- Forging C?S(Se) Bonds by Nickel-catalyzed Decarbonylation of Carboxylic Acid and Cleavage of Aryl Dichalcogenides
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A nickel-catalyzed decarbonylation of carboxylic acids cross-coupling protocol has been developed for the straightforward C?S(Se) bond formation. This reaction is promoted by a commercially-available, user-friendly, inexpensive, air and moisture-stable nickel precatalyst. Various carboxylic acids and a wide range of aryl dichalcogenide substrates were tolerated in this process which afforded products in good to excellent yields. In addition, the present reaction can be conducted on gram scale in good yield.
- Zhou, Jing-Ya,Zhu, Yong-Ming
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p. 2452 - 2461
(2021/06/28)
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- Perfluoroalkylation of Thiosulfonates: Synthesis of Perfluoroalkyl Sulfides
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A practical synthesis of perfluoroalkyl sulfides is described. The method employs stable and readily accessible thiosulfonates as new electrophiles with commercial nucleophilic perfluoroalkylating reagents. The mild reaction conditions allow access to a wide variety of both aryl- and alkyl-substituted perfluoroalkyl sulfides amenable to pharmaceutical development. Furthermore, the reaction operation is straightforward, odorless, does not produce toxic wastes, and, therefore should appeal to practitioners in industrial-scale productions.
- Luo, Ziwei,Yang, Xinkan,Tsui, Gavin Chit
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supporting information
p. 6155 - 6159
(2020/07/30)
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- Visible-light photocatalytic selective aerobic oxidation of thiols to disulfides on anatase TiO2
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This work presents the visible-light photocatalytic selective oxidation of thiols to disulfides with molecular oxygen (O2) on anatase TiO2. The high specific surface area of anatase TiO2 proved to be especially critical in
- Xu, Hui,Shi, Ji-Long,Lyu, Shaoshuai,Lang, Xianjun
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p. 1468 - 1473
(2020/04/29)
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- TEMPO visible light photocatalysis: The selective aerobic oxidation of thiols to disulfides
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TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) is well-established in orangocatalysis that usually work in synergy with transition-metal catalysis or semiconductor photocatalysis. Here, TEMPO was turned into a visible light photocatalyst to conduct the selective aerobic oxidation of thiols into disulfides. With O2 as an oxidant, a mild and efficient protocol for the selective oxidation of thiols into disulfides including symmetrical and unsymmetrical ones with 5 molpercent of TEPMO as a photocatalyst was developed at room temperature under the irradiation of 460 nm blue LEDs. It was found that a complex formed between TEMPO and thiols underpinned the visible light activity and disulfides were obtained in very high isolated yields. This work suggests that TEMPO takes diverse roles in for photocatalytic selective oxidative transformations with O2 as the oxidant.
- Xu, Hui,Zhang, Yu-Fei,Lang, Xianjun
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supporting information
p. 1520 - 1524
(2019/12/09)
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- SPIROPIPERIDINE ALLOSTERIC MODULATORS OF NICOTINIC ACETYLCHOLINE RECEPTORS
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The present disclosure relates to compounds of formula (I) that are useful as modulators of 7α nAChR, compositions comprising such compounds, and the use of such compounds for preventing, treating, or ameliorating disease, particularly disorders of the central nervous system such as cognitive impairments in Alzheimer's disease, Parkinson's disease, and schizophrenia, as well as for L-DOPA induced-dyskinesia and inflammation.
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-
Page/Page column 53-54
(2020/11/12)
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- Sulfonamide Synthesis through Electrochemical Oxidative Coupling of Amines and Thiols
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Sulfonamides are key motifs in pharmaceuticals and agrochemicals, spurring the continuous development of novel and efficient synthetic methods to access these functional groups. Herein, we report an environmentally benign electrochemical method which enables the oxidative coupling between thiols and amines, two readily available and inexpensive commodity chemicals. The transformation is completely driven by electricity, does not require any sacrificial reagent or additional catalysts and can be carried out in only 5 min. Hydrogen is formed as a benign byproduct at the counter electrode. Owing to the mild reaction conditions, the reaction displays a broad substrate scope and functional group compatibility.
- Laudadio, Gabriele,Barmpoutsis, Efstathios,Schotten, Christiane,Struik, Lisa,Govaerts, Sebastian,Browne, Duncan L.,No?l, Timothy
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supporting information
(2019/04/16)
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- Sulfonamide Synthesis through Electrochemical Oxidative Coupling of Amines and Thiols
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Sulfonamides are key motifs in pharmaceuticals and agrochemicals, spurring the continuous development of novel and efficient synthetic methods to access these functional groups. Herein, we report an environmentally benign electrochemical method which enables the oxidative coupling between thiols and amines, two readily available and inexpensive commodity chemicals. The transformation is completely driven by electricity, does not require any sacrificial reagent or additional catalysts and can be carried out in only 5 min. Hydrogen is formed as a benign byproduct at the counter electrode. Owing to the mild reaction conditions, the reaction displays a broad substrate scope and functional group compatibility.
- Laudadio, Gabriele,Barmpoutsis, Efstathios,Schotten, Christiane,Struik, Lisa,Govaerts, Sebastian,Browne, Duncan L.,No?l, Timothy
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supporting information
p. 5664 - 5668
(2019/04/17)
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- Fenton-Inspired C-H Functionalization: Peroxide-Directed C-H Thioetherification
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Substoichiometric iron mediates the thioetherification of unactivated aliphatic C-H bonds directed by resident silylperoxides. Upon exposure to a catalytic amount of iron(II) triflate, TIPS-protected peroxides bearing primary, secondary, and tertiary C-H sites undergo chemoselective thioetherification of remote C-H bonds with diaryl disulfides. The reaction demonstrates a broad substrate scope and functional group tolerance without the use of any noble metal additives. Mechanistic experiments suggest that the reaction proceeds through 1,5-H atom abstraction by a hydroxyl radical generated with iron.
- Groendyke, Brian J.,Modak, Atanu,Cook, Silas P.
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p. 13073 - 13091
(2019/10/10)
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- Sulfoxide ligand metal catalyzed oxidation of olefins
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The enantioselective synthesis of isochroman motifs has been accomplished via Pd(II)-catalyzed allylic C—H oxidation from terminal olefin precursors. Critical to the success of this goal was the development and utilization of a novel chiral aryl sulfoxide-oxazoline (ArSOX) ligand. The allylic C—H oxidation reaction proceeds with the broadest scope and highest levels asymmetric induction reported to date (avg. 92% ee, 13 examples ≥90% ee). Additionally, C(sp3)-N fragment coupling reaction between abundant terminal olefins and N-triflyl protected aliphatic and aromatic amines via Pd(II)/sulfoxide (SOX) catalyzed intermolecular allylic C—H amination is disclosed. A range of 52 allylic amines are furnished in good yields (avg. 76%) and excellent regio- and stereoselectivity (avg. >20:1 linear:branched, >20:1 E:Z). For the first time, a variety of singly activated aromatic and aliphatic nitrogen nucleophiles, including ones with stereochemical elements, can be used in fragment coupling stiochiometries for intermolecular C—H amination reactions.
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Page/Page column 56
(2019/05/09)
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- Ni/NHC-catalyzed cross-coupling of methyl sulfinates and amines for direct access to sulfinamides
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It was reported to develop a simple and convenient method for the Ni/NHC-catalyzed cross-coupling of methyl sulfinates and amines without an acid/base to afford secondary or tertiary sulfinamides in moderate to good yields. The method can provide the desired products with broad substrate scope, good chemoselectivity and good functional group compatibility. The presented approach may enrich the Ni/NHC catalyst system and promote the applications of methyl sulfinates in the organic sulfur chemistry.
- Li, Gang-Jian,Pan, You-Lu,Liu, Yan-Ling,Xu, Hai-Feng,Chen, Jian-Zhong
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supporting information
(2019/10/28)
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- Base-controlled Fe(Pc)-catalyzed aerobic oxidation of thiols for the synthesis of S-S and S-P(O) bonds
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Fe(Pc)-Catalyzed aerobic oxidation of thiols for the synthesis of disulfides has been developed under mild reaction conditions. In addition, an aerobic oxidative cross-dehydrogenative coupling (CDC) reaction of thiols with P(O)-H compounds (H-phosphonates and H-phosphine oxide) for the formation of S-P(O) bonds has been demonstrated under the Fe(Pc) catalysis system with a base additive. Control experiments revealed that the use of a base (DIPA) in this system controls the synthetic pathways in which thiophosphates are formed.
- Huang, Hai,Ash, Jeffrey,Kang, Jun Yong
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p. 4236 - 4242
(2018/06/21)
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- Preparation of Propargylic Sulfinates and their [2,3]-Sigmatropic Rearrangement to Allenic Sulfones
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The scope of the [2,3]-sigmatropic rearrangement of propargylic sulfinates to allenic sulfones by silver catalysis was expanded. A series of new propargylic sulfinate esters was generated from a variety of aromatic and heteroaromatic sulfonyl chlorides an
- Tata, Rama Rao,Hampton, Carissa S.,Harmata, Michael
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supporting information
p. 1232 - 1241
(2017/04/11)
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- Electron Transfer Mechanism in the Oxidation of Aryl 1-Methyl-1-phenylethyl Sulfides Promoted by Nonheme Iron(IV)-Oxo Complexes: The Rate of the Oxygen Rebound Process
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The oxidation of aryl 1-methyl-1-phenylethyl sulfides promoted by the nonheme iron(IV)-oxo complexes [(N4Py)FeIVO]2+ and [(Bn-TPEN)FeIVO]2+ occurs by an electron transfer-oxygen rebound (ET-OT) mechanism leadi
- Barbieri, Alessia,Del Giacco, Tiziana,Di Stefano, Stefano,Lanzalunga, Osvaldo,Lapi, Andrea,Mazzonna, Marco,Olivo, Giorgio
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p. 12382 - 12387
(2016/12/23)
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- Tunable and Practical Synthesis of Thiosulfonates and Disulfides from Sulfonyl Chlorides in the Presence of Tetrabutylammonium Iodide
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A tunable and practical synthesis of electrophilic sulfenylating reagents, thiosulfonates and disulfides, from inexpensive and easily available sulfonyl chlorides, has been developed. By appropriate choice of solvents, the reaction of sulfonyl chlorides and tetrabutylammonium iodide gave the target products in good to excellent yields, respectively. These transformations probably proceed through a reducing–coupling pathway. (Figure presented.).
- Zheng, Yong,Qing, Feng-Ling,Huang, Yangen,Xu, Xiu-Hua
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supporting information
p. 3477 - 3481
(2016/11/13)
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- Iodide-Catalyzed Synthesis of Secondary Thiocarbamates from Isocyanides and Thiosulfonates
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A new method for the synthesis of secondary thiocarbamates from readily available isocyanides and thiosulfonates with broad functional group tolerance is reported. The reaction proceeds under mild reaction conditions in isopropanol and is catalyzed by inexpensive sodium iodide.
- Mampuys, Pieter,Zhu, Yanping,Sergeyev, Sergey,Ruijter, Eelco,Orru, Romano V. A.,Van Doorslaer, Sabine,Maes, Bert U. W.
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supporting information
p. 2808 - 2811
(2016/07/06)
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- On the Origins of Nonradiative Excited State Relaxation in Aryl Sulfoxides Relevant to Fluorescent Chemosensing
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We provide herein a mechanistic analysis of aryl sulfoxide excited state processes, inspired by our recent report of aryl sulfoxide based fluorescent chemosensors. The use of aryl sulfoxides as reporting elements in chemosensor development is a significan
- Kathayat, Rahul S.,Yang, Lijun,Sattasathuchana, Tosaporn,Zoppi, Laura,Baldridge, Kim K.,Linden, Anthony,Finney, Nathaniel S.
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supporting information
p. 15889 - 15895
(2016/12/22)
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- Enantioselective Allylic C?H Oxidation of Terminal Olefins to Isochromans by Palladium(II)/Chiral Sulfoxide Catalysis
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The enantioselective synthesis of isochroman motifs has been accomplished by palladium(II)-catalyzed allylic C?H oxidation from terminal olefin precursors. Critical to the success of this goal was the development and utilization of a novel chiral aryl sul
- Ammann, Stephen E.,Liu, Wei,White, M. Christina
-
supporting information
p. 9571 - 9575
(2016/08/10)
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- Synthesis of β-Hydroxysulfides from Thiophenols and Disulfides with tert-Butyl Hydroperoxide as the Oxidant and Reactant
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In this Communication, we developed a new procedure for the synthesis of β-hydroxysulfides from thiophenols or diaryl disulfides with TBHP as the oxidant. In the presence of zinc iodide or potassium iodide, with TBHP as the oxidant and pre-reactant, thiophenols and diaryl disulfides reacted with the methyl group of tBuOH smoothly and selectivity to give the corresponding 2-methyl-1-(arylthio)propan-2-ols as the terminal products in moderate to good yields.
- Feng, Jian-Bo,Wu, Xiao-Feng
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p. 315 - 318
(2016/08/19)
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- Accessing Ni(III)-thiolate versus Ni(II)-thiyl bonding in a family of Ni-N2S2 synthetic models of NiSOD
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Superoxide dismutase (SOD) catalyzes the disproportionation of superoxide (O2?-) into H2O2 and O2(g) by toggling through different oxidation states of a first-row transition metal ion at its active site. Ni-containing SODs (NiSODs) are a distinct class of this family of metalloenzymes due to the unusual coordination sphere that is comprised of mixed N/S-ligands from peptide-N and cysteine-S donor atoms. A central goal of our research is to understand the factors that govern reactive oxygen species (ROS) stability of the Ni-S(Cys) bond in NiSOD utilizing a synthetic model approach. In light of the reactivity of metal-coordinated thiolates to ROS, several hypotheses have been proffered and include the coordination of His1-Nδ to the Ni(II) and Ni(III) forms of NiSOD, as well as hydrogen bonding or full protonation of a coordinated S(Cys). In this work, we present NiSOD analogues of the general formula [Ni(N2S)(SR′)]-, providing a variable location (SR′ = aryl thiolate) in the N2S2 basal plane coordination sphere where we have introduced o-amino and/or electron-withdrawing groups to intercept an oxidized Ni species. The synthesis, structure, and properties of the NiSOD model complexes (Et4N)[Ni(nmp)(SPh-o-NH2)] (2), (Et4N)[Ni(nmp)(SPh-o-NH2-p-CF3)] (3), (Et4N)[Ni(nmp)(SPh-p-NH2)] (4), and (Et4N)[Ni(nmp)(SPh-p-CF3)] (5) (nmp2- = dianion of N-(2-mercaptoethyl)picolinamide) are reported. NiSOD model complexes with amino groups positioned ortho to the aryl-S in SR′ (2 and 3) afford oxidized species (2ox and 3ox) that are best described as a resonance hybrid between Ni(III)-SR and Ni(II)-?SR based on ultraviolet-visible (UV-vis), magnetic circular dichroism (MCD), and electron paramagnetic resonance (EPR) spectroscopies, as well as density functional theory (DFT) calculations. The results presented here, demonstrating the high percentage of S(3p) character in the highest occupied molecular orbital (HOMO) of the four-coordinate reduced form of NiSOD (NiSODred), suggest that the transition from NiSODred to the five-coordinate oxidized form of NiSOD (NiSODox) may go through a four-coordinate Ni-?S(Cys) (NiSODox-Hisoff) that is stabilized by coordination to Ni(II).
- Broering, Ellen P.,Dillon, Stephanie,Gale, Eric M.,Steiner, Ramsey A.,Telser, Joshua,Brunold, Thomas C.,Harrop, Todd C.
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p. 3815 - 3828
(2015/05/04)
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- Vis/NIR light driven mild and clean synthesis of disulfides in the presence of Cu2(OH)PO4 under aerobic conditions
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A highly efficient one-pot strategy has been developed for the synthesis of disulfide in the presence of air under the irradiation of Vis/NIR light. Copper hydroxyphosphate (CHP) Cu2(OH)PO4, has been used as a Vis/NIR active photocatalyst. Disulfide forms on the surface of the catalyst by a radical mechanism. The protocol is useful for solvent free disulfide synthesis from a variety of thiols. This journal is
- Shah, Sk. Sheriff,Karthik,Singh, N. D. Pradeep
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p. 45416 - 45419
(2015/06/02)
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- HERBICIDE COMPOSITION
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There is provided a herbicidal composition containing a cyclohexanone compound represented by Formula (I) and at least one compound selected from Group A. Group A: consisting of benoxacor, cloquintocet-mexyl, cyometrinil, dichlormid, fenchlorazole-ethyl,
- -
-
Paragraph 0872-0875
(2015/11/03)
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- Hammett correlations as test of mechanism of CO-induced disulfide elimination from dinitrosyl iron complexes
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The displacement of RS from [(NHC)(SPh)Fe(NO)2] (NHC = N-heterocyclic carbene) by carbon monoxide follows associative kinetics, rate = k [CO]1 [(NHC)(SPh)Fe(NO)2]1, resulting in reduction of the oxidized form of
- Pulukkody, Randara,Kyran, Samuel J.,Drummond, Michael J.,Hsieh, Chung-Hung,Darensbourg, Donald J.,Darensbourg, Marcetta Y.
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p. 3795 - 3802
(2014/11/08)
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- The Chan-Lam reaction of chalcogen elements leading to aryl chalcogenides
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A copper-catalyzed chalcogenation of arylboronic acids with elemental sulfur or selenium is established, which provides diaryl disulfides or diaryl monoselenides in moderate to good yields with excellent selectivities, respectively. Moreover, after sequential reduction and coupling with aryl/alkyl iodides in one pot, unsymmetrical monosulfides were obtained in good yields.
- Yu, Jin-Tao,Guo, Huan,Yi, Yuanqiuqiang,Fei, Haiyang,Jiang, Yan
-
supporting information
p. 749 - 752
(2014/04/03)
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- Mechanistic insights into the interface-directed transformation of thiols into disulfides and molecular hydrogen by visible-light irradiation of quantum dots
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Quantum dots (QDs) offer new and versatile ways to harvest light energy. However, there are few examples involving the utilization of QDs in organic synthesis. Visible-light irradiation of CdSe QDs was found to result in virtually quantitative coupling of a variety of thiols to give disulfides and H2 without the need for sacrificial reagents or external oxidants. The addition of small amounts of nickel(II) salts dramatically improved the efficiency and conversion through facilitating the formation of hydrogen atoms, thereby leading to faster regeneration of the ground-state QDs. Mechanistic studies reveal that the coupling reaction occurs on the QD surfaces rather than in solution and offer a blueprint for how these QDs may be used in other photocatalytic applications. Because no sacrificial agent or oxidant is necessary and the catalyst is reusable, this method may be useful for the formation of disulfide bonds in proteins as well as in other systems sensitive to the presence of oxidants. Copyright
- Li, Xu-Bing,Li, Zhi-Jun,Gao, Yu-Ji,Meng, Qing-Yuan,Yu, Shan,Weiss, Richard G.,Tung, Chen-Ho,Wu, Li-Zhu
-
supporting information
p. 2085 - 2089
(2014/03/21)
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- CYCLOHEXANONE COMPOUNDS AND HERBICIDES COMPRISING THE SAME
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The present invention provides a compound having an excellent efficacy for controlling weeds. A cyclohexanone compound of the formula (I): wherein m is an integer of 1, 2 or 3; n is an integer of any one of 1 to 5; X represents CH2, O, S, S(O)
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Paragraph 0745-0748
(2014/08/19)
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- Use of base control to provide high selectivity between diaryl thioether and diaryl disulfide for C-S coupling reactions of aryl halides and sulfur and a mechanistic study
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Previous studies have reported that S-arylation produces diaryl disulfide when the precursors include sulfur powder and aryl halide using CuI as the catalyst. However, our research has revealed that the use of different bases in the above S-arylation process results in the coproduction of diarylsulfane and diaryldisulfane. In addition, we have demonstrated that the ratio of the two products can be controlled by selecting the alkalinity of the bases. 1H NMR spectra showed that diaryldisulfane was the first product, which became the reagent in a reaction with aryl halide to form diarylsulfane through CuI catalysis. Various aryl halides were tested to enhance the selectivity between diarylsulfane and diaryldisulfane using various different bases, leading to the following principles. A weak base, such as metal carbonate or acetate, results in the production of only diaryldisulfane; a strong base, such as metal hydroxide, results in the production of both diaryldisulfane and diarylsulfane. According to DFT calculations, hydroxide ions, which were exchanged for iodide and bonded with Cu, affected Cu electrons more strongly to reduce diaryl disulfide.
- Chen, Hsing-Ying,Peng, Wei-Te,Lee, Ying-Hsien,Chang, Yu-Lun,Chen, Yen-Jen,Lai, Yi-Chun,Jheng, Nai-Yuan,Chen, Hsuan-Ying
-
supporting information
p. 5514 - 5522
(2013/11/06)
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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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- Organosulfur compounds as pre-exposure therapy for threat agents.
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A series of symmetric (Ar-S-S-Ar) and unsymmetric (Ar-S-S-CH2CH2NH3+Cl-) disulfides have been prepared and evaluated as potential cyanoprotective agents. Target compounds have been prepared by known methods and/or methods developed by us specifically for this program, e.g. reaction of a thiol with 2,2'-dithiobis(benzothiazole) (BT-S-S-BT) followed by reaction with a second thiol. Both 4-methoxyphenyl disulfide and 2-aminoethyl-4-methoxyphenyl disulfide hydrochloride are cyanoprotective against 2-LD50 of injected cyanide. Evaluation of both symmetric and unsymmetric related disulfides indicates that structural requirements for cyanoprotective activity are stringent and strongly suggest that protection is enzyme mediated. In addition to cyanoprotective action, initial results suggest that unsymmetric disulfides may evolve into effective antimustard agents.
- Ternay Jr.,Brzezinska,Sorokin,Cook,Lyaschenko
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-