- A Route to Chiral Epoxypyrroloindoles via Oxiranyl Radical Cyclization
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An oxiranyl radical has been generated from a glycidic acid via the thiohydroxamic acid anhydride route.The radical has been shown to undergo cyclization, a process, which to our knowledge, has not been reported previously.The structure and the reactivity of the indole and dihydroindole products of the cyclization are discussed.
- Ziegler, Frederick E.,Harran, Patrick G.
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- Visible-light-induced synthesis of benzothiophenes and benzoselenophenes via the annulation of thiophenols or 1,2-diphenyldiselane with alkynes
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An effective metal-free photoredox-mediated tandem addition/cyclization reaction of thiophenols or 1,2-diphenyldiselane with alkynes leads to 2,3-disubstituted benzothiophenes and benzoselenophenes. Blue light irradiation of the organic dye, Mes-Acr-Mesu
- Xia, Xiao-Feng,Zhang, Guo-Wei,Zhu, Su-Li
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- Solid state oxidation of thiols to disulfides using ammonium persulfate
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A solid state method for the oxidation of thiols is described that uses benign oxidant, ammonium persulfate.
- Varma, Rajender S.,Meshram, Harshadas M.,Dahiya, Rajender
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- Urea- Hydrogen Peroxide (UHP) oxidation of thiols to the corresponding disulfides promoted by maleic anhydride as mediator
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Urea-hydrogen peroxide (UHP) was used in the presence of maleic anhydride as mediator in a simple and convenient method for the oxidation in high yield of some thiols to the corresponding disulfides. Peroxymaleic acid formed in situ from the reaction of U
- Karami, Bahador,Montazerozohori,Habibi
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- Synthesis of pyridothietone by flash vacuum pyrolysis of 2-mercaptonicotinic acid
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The temperature dependence of products formed from flash vacuum pyrolysis (FVP) of 2-mercaptonicotinic acid 4 has been studied. FVP of 4 at 550°C and ca. 1×10-2 torr gave pyridothietone 3b and a trimer 5 as the major products. At higher temperature (800°C), FVP of 4 gave 2-mercaptopyridine 6 as the major product and 2,2′-dipyridyl disulphide 7 as the minor one.
- Chou, Chin-Hsing,Chiu, Shao-Jung,Liu, Wei-Min
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- l-Arginine complex of copper on modified core–shell magnetic nanoparticles as reusable and organic–inorganic hybrid nanocatalyst for the chemoselective oxidation of organosulfur compounds
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In this paper, we report the fabrication and characterization of a stable heterogeneous nanostructure catalyst of copper immobilized on Fe3O4@SiO2@l-Arginine, for the oxidation of sulfides and oxidative coupling of thiols. The prepared nanocatalyst has been characterized by different techniques such as FTIR, XRD, SEM, TEM and TGA. These nanoparticles were the effective catalyst for selective oxidation of sulfides and oxidative coupling of thiols using 30% H2O2. The suggested method offers several prominent advantages such as mild condition, use of magnetically reusable catalyst, simple workup procedure, good to high yields of products and great selectivity.
- Nikoorazm, Mohsen,Moradi, Parisa,Noori, Nourolah,Azadi, Gouhar
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p. 467 - 478
(2020/09/01)
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- Copper based on diaminonaphthalene-coated magnetic nanoparticles as robust catalysts for catalytic oxidation reactions and C-S cross-coupling reactions
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In this work, the immobilization of copper(ii) on the surface of 1,8-diaminonaphthalene (DAN)-coated magnetic nanoparticles provides a highly active catalyst for the oxidation reaction of sulfides to sulfoxides and the oxidative coupling of thiols to disulfides using hydrogen peroxide (H2O2). This catalyst was also applied for the one-pot synthesis of symmetrical sulfidesviathe reaction of aryl halides with thiourea as the sulfur source in the presence of NaOH instead of former strongly basic and harsh reaction conditions. Under optimum conditions, the synthesis yields of sulfoxides, symmetrical sulfides, and disulfides were about 99%, 95%, and 96% respectively with highest selectivity. The heterogeneous copper-based catalyst has advantages such as the easy recyclability of the catalyst, the easy separation of the product and the less wastage of products during the separation of the catalyst. This heterogeneous nanocatalyst was characterized by FESEM, FT-IR, VSM, XRD, EDX, ICP and TGA. Furthermore, the recycled catalyst can be reused for several runs and is economically effective.
- Yarmohammadi, Nasrin,Ghadermazi, Mohammad,Mozafari, Roya
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p. 9366 - 9380
(2021/03/16)
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- Photo-induced thiolate catalytic activation of inert Caryl-hetero bonds for radical borylation
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Substantial effort is currently being devoted to obtaining photoredox catalysts with high redox power. Yet, it remains challenging to apply the currently established methods to the activation of bonds with high bond dissociation energy and to substrates with high reduction potentials. Herein, we introduce a novel photocatalytic strategy for the activation of inert substituted arenes for aryl borylation by using thiolate as a catalyst. This catalytic system exhibits strong reducing ability and engages non-activated Caryl–F, Caryl–X, Caryl–O, Caryl–N, and Caryl–S bonds in productive radical borylation reactions, thus expanding the available aryl radical precursor scope. Despite its high reducing power, the method has a broad substrate scope and good functional-group tolerance. Spectroscopic investigations and control experiments suggest the formation of a charge-transfer complex as the key step to activate the substrates.
- K?nig, Burkhard,Wang, Hua,Wang, Shun
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supporting information
p. 1653 - 1665
(2021/06/17)
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- Direct Synthesis of N-Difluoromethyl-2-pyridones from Pyridines
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A novel method for the synthesis of N-difluoromethyl-2-pyridones was described. This protocol enables the synthesis of N-difluoromethyl-2-pyridones from readily available pyridines using mild reaction conditions that are compatible with a wide range of functional groups. The preliminary mechanistic study revealed that N-difluoromethylpyridinium salts were the key intermediates to complete this conversion.
- Zhou, Sen,Hou, Xiaoya,Yang, Kai,Guo, Minjie,Zhao, Wentao,Tang, Xiangyang,Wang, Guangwei
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p. 6879 - 6887
(2021/05/29)
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- Synthesis and characterization of VO–vanillin complex immobilized on MCM-41 and its facile catalytic application in the sulfoxidation reaction, and synthesis of 2,3-dihydroquinazolin-4(1H)-ones and disulfides in green media
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In this work, a vanillin complex is immobilized onto MCM-41 and characterized by FT-IR, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, thermogravimetric analysis, and BET techniques. This supported Schiff base complex was found to be an efficient and recoverable catalyst for the chemoselective oxidation of sulfides into sulfoxides and thiols into their corresponding disulfides (using hydrogen peroxide as a green oxidant) and also a suitable catalyst for the preparation of 2,3-dihydroquinazolin-4(1H)-one derivatives in water at 90°C. Using this protocol, we show that a variety of disulfides, sulfoxides, and 2,3-dihydroquinazolin-4(1H)-one derivatives can be synthesized in green conditions. The catalyst can be recovered and recycled for further reactions without appreciable loss of catalytic performance.
- Nikoorazm, Mohsen,Khanmoradi, Maryam
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p. 1477 - 1489
(2020/03/11)
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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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- 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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- Method for synthesizing symmetric disulfide compound by taking aryl hydrazine and S8 as raw materials
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The invention relates to a method for synthesizing a symmetric disulfide compound by taking aryl hydrazine and S8 as raw materials, and belongs to the technical field of organic synthesis; the methodis characterized in that the aryl hydrazine compound and S8 are used as substrates to react in a reaction solvent under the promotion of alkali to generate the symmetric disulfide organic compound, the reaction gas atmosphere is air or oxygen, the reaction temperature is 40 DEG C-100 DEG C, and the reaction time is 4-24 hours. The synthesis steps are simple, the reaction conditions are mild, S8 which is widely distributed in nature, low in price and easy to obtain is used as a sulfur source, S-S bonds can be constructed only under the promotion of alkali without transition metal catalysis, theyield is as high as 95%, the applicable reaction substrate range is wide, the operation is simple and feasible, the synthesis cost is low, the environmental pollution is small, and a new thought is provided for the synthesis of the symmetric disulfide organic compound.
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Paragraph 0049-0052
(2020/11/23)
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- Natural gallic acid catalyzed aerobic oxidative coupling with the assistance of MnCO3 for synthesis of disulfanes in water
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The formation of S-S bonds has great significance and value in synthetic chemistry and bioscience. To pursue a sustainable approach for such a synthesis, an aerobic oxidative coupling method for the efficient preparation of organic disulfanes, using a low-toxic natural gallic acid as an organocatalyst, inexpensive MnCO3 as a cocatalyst, O2 as the terminal oxidant and water as the solvent, has been successfully developed. Such metal-organic cooperative catalytic protocol provided an access to various symmetrical and unsymmetrical disulfanes in up to 99% yield. Gram scale synthesis with practical convenience and low loading of catalysts further illustrates the practicability of our method.
- Song, Lijuan,Li, Wenhao,Duan, Wenxue,An, Jichao,Tang, Shanyu,Li, Longjia,Yang, Guanyu
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supporting information
p. 1432 - 1438
(2019/03/26)
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- Biocatalytic synthesis of diaryl disulphides and their bio-evaluation as potent inhibitors of drug-resistant Staphylococcus aureus
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Staphylococcus aureus is a WHO Priority II pathogen for its capability to cause acute to chronic infections and to resist antibiotics, thus severely impacting healthcare systems worldwide. In this context, it is urgently desired to discover novel molecules to thwart the continuing emergence of antimicrobial resistance. Disulphide containing small molecules has gained prominence as antibacterials. As their conventional synthesis requires tedious synthetic procedure and sometimes toxic reagents, a green and environmentally benign protocol for their synthesis has been developed through which a series of molecules were obtained and evaluated for antibacterial activity against ESKAPE pathogen panel. The hit compound was tested for cytotoxicity against Vero cells to determine its selectivity index and time-kill kinetics was determined. The activity of hit was determined against a panel of S. aureus multi-drug resistant clinical isolates. Also, its ability to synergize with FDA approved drugs was tested as was its ability to reduce biofilm. We identified bis(2-bromophenyl) disulphide (2t) as possessing equipotent antimicrobial activity against S. aureus including MRSA and VRSA strains. Further, 2t exhibited a selectivity index of 25 with concentration-dependent bactericidal activity, synergized with all drugs tested and significantly reduced preformed biofilm. Taken together, 2t exhibits all properties to be positioned as novel scaffold for anti-staphylococcal therapy.
- Saima,Soni, Isha,Lavekar, Aditya G.,Shukla, Manjulika,Equbal, Danish,Sinha, Arun K.,Chopra, Sidharth
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p. 171 - 178
(2019/01/04)
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- Fluorium-Initiated Dealkylative Cyanation of Thioethers to Thiocyanates
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Thioethers are converted to thiocyanates via fluorium-initiated dealkylative cyanation. Selectfluor is used as the oxidant, and trimethylsilyl cyanide is used as the cyanation reagent. The well-streamlined procedure is user-friendly, operationally simple, and step-economical. The current mechanistic studies show that the sulfur radical cation and cyano radical are both involved. They combine to deliver cyanosulfonium, an intermediate toward thiocyanate after dealkylation. Alternatively, a nucleophilic mechanism is also possible. Our dealkyaltive cyanation is also efficient in synthesizing thiocyanates with strongly electrophilic functionalities.
- Chen, Yang,Qi, Hongyi,Chen, Ning,Ren, Demin,Xu, Jiaxi,Yang, Zhanhui
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supporting information
p. 9044 - 9050
(2019/08/12)
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- Synthesis and antiproliferative activities of conjugates of paclitaxel and camptothecin with a cyclic cell-penetrating peptide
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Cell-penetrating peptide [WR]5 has been previously shown to be an efficient molecular transporter for various hydrophilic and hydrophobic molecules. The peptide was synthesized using Fmoc/tBu solid-phase chemistry, and one arginine was replaced with one lysine to enable the conjugation with the anticancer drugs. Paclitaxel (PTX) was functionalized with an esterification reaction at the C20 hydroxyl group of PTX with glutaric anhydride and conjugated with the cyclic peptide [W(WR)4K(βAla)] in DMF to obtain the peptide-drug conjugate PTX1. Furthermore, camptothecin (CPT) was modified at the C(20)-hydroxyl group through the reaction with triphosgene. Then, it was conjugated with two functionalized cyclic peptides through a formyl linker affording two different conjugates, namely CPT1 and CPT2. All the conjugates showed better water solubility as compared to the parent drug. The cytotoxicity assay of the drugs and their conjugates with the peptides were evaluated in the human breast cancer MCF-7 cell line. PTX inhibited cell proliferation by 39% while the PTX-peptide conjugate inhibited the proliferation by ~18% after 72 h incubation. On the other hand, CPT, CPT1, and CPT2 reduced the cell proliferation by 68%, 39%, and 62%, respectively, in the MCF-7 cell lines at 5 μM concentration after 72 h incubation.
- El-Sayed, Naglaa Salem,Shirazi, Amir Nasrolahi,Sajid, Muhammad Imran,Park, Shang Eun,Parang, Keykavous,Tiwari, Rakesh Kumar
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- Utilizing 2-phenylpropanal as coupling partner for C-S bond formation via sequential thioarylation and decarbonylation process: A novel strategy for the synthesis of aryl alkyl sulfides
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In this study, first direct access to aryl alkyl sulfides employing 2-phenylpropanal as coupling partner is reported. Diaryl disulfides react with this aldehyde in the presence of morpholine and produce the corresponding sulfide products in high yields. In another part, disulfides are in situ generated in the reaction mixture from aryl halides/CuI/Cyanodithioformate and coupled with 2-phenylpropanal to access aryl alkyl sulfides.
- Shaikhi Shahidzadeh, Elham,Nowrouzi, Najmeh,Abbasi, Mohammad
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- Synthesis and characterization of sulfamic acid supported on Fe3O4 nanoparticles: A green, versatile and magnetically separable acidic catalyst for oxidation reactions and Knoevenagel condensation
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Sulfamic acid immobilized on diethylenetriamine functionalized Fe3O4 nanoparticles (SA-DETA-Fe3O4) was successfully prepared and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), thermo gravimetric analysis (TGA), X-Ray diffraction (XRD) and scanning electron microscopy (SEM). The sulfamic acid was found as a magnetically separable and highly active catalyst for the oxidative coupling thiols, oxidation of sulfides. Furthermore, the SA-DETA-Fe3O4 showed the high catalytic activity in Knoevenagel condensation of aromatic aldehydes with active methylene compounds (malononitrile and ethyl cynoacetate). The nanosolid catalyst could be easily recovered by a simple magnetic separation and reused for many cycles without deterioration in catalytic activity.
- Shiri, Lotfi,Narimani, Hojatollah,Kazemi, Mosstafa
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- Synthesis and characterization of oxo-vanadium complex anchored onto SBA-15 as a green, novel and reusable nanocatalyst for the oxidation of sulfides and oxidative coupling of thiols
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Abstract: The present work describes the synthesis of a new oxo-vanadium complex immobilized on SBA-15 nanostructure as an efficient catalyst for oxidation of sulfides and oxidative coupling of thiols. Characterization of the resultant AMPD@SBA-15 nanostructure was performed by various physico-chemical techniques such as Fourier transform infrared spectroscopy, transmission and scanning electron microscopies, energy-dispersive X-ray spectroscopy, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, thermal gravimetric analysis, and N2 adsorption and desorption. The results of the developed procedure bring several benefits such as the use of commercially available, ecologically benign, operational simplicity, and cheap and chemically inert reagents. It shows good reaction times, practicability and high efficiency, and is easily recovered from the reaction mixture by simple filtration and reused for several consecutive cycles without noticeable change in its catalytic activity. More importantly, high efficiency, simple and an inexpensive procedure, commercially available materials, easy separation, and an eco-friendly procedure are the several advantages of the currently employed heterogeneous catalytic system.
- Tamoradi, Taiebeh,Ghadermazi, Mohammad,Ghorbani-Choghamarani, Arash,Molaei, Somayeh
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p. 4259 - 4276
(2018/03/21)
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- Ni(II)-Adenine complex coated Fe3O4 nanoparticles as high reusable nanocatalyst for the synthesis of polyhydroquinoline derivatives and oxidation reactions
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In the present study, Fe3O4 nanoparticles were prepared via simple and versatile procedure. Then, a novel and green catalyst was synthesized by the immobilization of Ni on Fe3O4 nanoparticles coated with adenine. The activity of this nanostructure compound was examined for the oxidation of sulfides, oxidative coupling of thiols and synthesis of polyhydroquinolines. The prepared catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray Diffraction (XRD), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM) measurements. This organometallic catalyst was recovered by the assistance of an external magnetic field from the reaction mixture and reused for seven continuous cycles without noticeable change in its catalytic activity.
- Tamoradi, Taiebeh,Ghadermazi, Mohammad,Ghorbani-Choghamarani, Arash
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- An Organodiselenide with Dual Mimic Function of Sulfhydryl Oxidases and Glutathione Peroxidases: Aerial Oxidation of Organothiols to Organodisulfides
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A novel organodiselenide, which mimics sulfhydryl oxidases and glutathione peroxidase (GPx) enzymes for oxidation of thiols by oxygen and hydrogen peroxide, respectively, into disulfides has been presented. The developed catalyst oxidizes an array of organothiols into respective disulfides in practical yields by using aerial O2 to avoid any reagents/additives, base, and light source. The synthesized diselenide also catalyzes the reduction of hydrogen peroxide into water by following the GPx enzymatic catalytic cycle with a reduction rate of 49.65 ± 3.7 μM·min-1.
- Rathore, Vandana,Upadhyay, Aditya,Kumar, Sangit
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supporting information
p. 6274 - 6278
(2018/10/05)
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- Unsymmetrical Disulfide Synthesis through Photoredox Catalysis
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A facile and eco-friendly visible light-mediated synthesis of symmetrical and unsymmetrical disulfides using tris[2-phenylpyridinato-C2,N]iridium(III) under additive and oxidant free conditions has been disclosed. The developed method is very mild, several functional group tolerant and highly atom economical requiring extremely low amount of catalyst loading (0.5 mol%). (Figure presented.).
- Dethe, Dattatraya H.,Srivastava, Aparna,Dherange, Balu D.,Kumar, B. Vijay
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supporting information
p. 3020 - 3025
(2018/08/23)
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- PTAB mediated open air synthesis of sulfonamides, thiosulfonates and symmetrical disulfanes
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A facile methodology has been described which has successfully simplified the generation of sulfonamides, thiosulfonates and symmetric disulfanes. This “trio” of reactions occur in an open air metal free atmosphere and has also been scaled up to grams making it suitable for commercialization. The reactions also have been successfully carried out with asymmetric variants, thus contributing to the chiral pool. The user friendly “trio” enables easy generation of these versatile sulfur analogues and the reaction condition employed depict an economic outline.
- Sarkar, Debayan,Ghosh, Manoj Kumar,Rout, Nilendri
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supporting information
p. 2360 - 2364
(2018/05/24)
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- Pyridinethiol-Assisted Dissolution of Elemental Gold in Organic Solutions
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Dissolution of elemental gold in organic solutions is a contemporary approach to lower the environmental burden associated with gold recycling. Herein, we describe fundamental studies on a highly efficient method for the dissolution of elemental Au that is based on DMF solutions containing pyridine-4-thiol (4-PSH) as a reactive ligand and hydrogen peroxide as an oxidant. Dissolution of Au proceeds through several elementary steps: isomerization of 4-PSH to pyridine-4-thione (4-PS), coordination with Au0, and then oxidation of the Au0 thione species to AuI simultaneously with oxidation of free pyridine thione to elemental sulfur and further to sulfuric acid. The final dissolution product is a AuI complex bearing two 4-PS ligands and SO42? as a counterion. The ligand is crucial as it assists the oxidation process and stabilizes and solubilizes the formed Au cations.
- R?is?nen, Minna,Heli?vaara, Eeva,Al-Qaisi, Feda'a,Muuronen, Mikko,Eronen, Aleksi,Liljeqvist, Henri,Nieger, Martin,Kemell, Marianna,Moslova, Karina,H?m?l?inen, Jani,Lagerblom, Kalle,Repo, Timo
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supporting information
p. 17104 - 17109
(2018/12/04)
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- A novel dual-nano assisted synthesis of symmetrical disulfides from aryl/alkyl halides
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Here, we have reported a novel approach towards dual-nano assisted synthesis of disulfides from coupling of alkyl/aryl halides and sulfur nanoparticles. The indium oxide nanoparticles as catalyst expedite the conversion and sulfur nanoparticle notably enhances the miscibility, providing a faster, high yielding and cost-effective process in ethanol-water system. The method has synthetic advantages in terms of mild reaction framework, catalyst regeneration, and absence of any sulfide or polysulfide linkage as by-product leading to a column free synthesis. A variety of alkyl, aryl and heteroaryl symmetrical disulfides are obtained in good to excellent yields up to exceeding 98%.
- Devi, Namita,Hazarika, Sukanya,Gogoi, Prasanta,Barman, Pranjit
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p. 1927 - 1938
(2018/07/21)
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- Method for catalyzing molecular oxygen to oxidize into disulfides with S-S bonds in aqueous phase
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The invention provides a method for catalyzing molecular oxygen to oxidize into disulfides with S-S bonds in an aqueous phase. The method includes taking water-soluble transition metal phthalocyanine compounds as catalysts, and enabling sulfhydryl compounds to react for 1-30 hours in the aqueous phase at a pressure of 0.01-1.00 Mpa, at 40-100 DEG C and in the presence of oxygen or air so as to obtain the disulfides with the S-S bonds. The method has the advantages that reaction is conducted in the aqueous phase, so that addition of other organic solvents is unneeded; the catalysts are high in catalytic activity, high in reaction efficiency and reusable; the method is simple in synthetic process, high in product selectivity, fewer in byproducts and wastes and environment friendly, thereby being promising in industrial application prospect.
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Paragraph 0022; 0023; 0029; 0030
(2017/08/29)
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- Reusable cobalt-phthalocyanine in water: Efficient catalytic aerobic oxidative coupling of thiols to construct S-N/S-S bonds
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A new aerobic oxidative coupling of thiols in water to construct sulfenamides or disulfides was developed, utilizing cobalt(ii)phthalocyanine-tetra-sodium sulfonate as the catalyst and O2 as the oxidant. The mother liquor could be recycled up to 20 times with negligible loss of activity and only a minor decrease of product yield.
- Dou, Yingchao,Huang, Xin,Wang, Hao,Yang, Liting,Li, Heng,Yuan, Bingxin,Yang, Guanyu
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supporting information
p. 2491 - 2495
(2017/07/17)
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- Cu(II) immobilized on Fe3O4–diethylenetriamine: A new magnetically recoverable catalyst for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones and oxidative coupling of thiols
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Cu(II) immobilized on Fe3O4–diethylenetriamine was designed as a new, inexpensive and efficient heterogeneous catalyst for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones and the oxidative coupling of thiols. The structure of the nanomagnetic catalyst was comprehensively characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, vibrating sample magnetometry, thermogravimetric analysis, X-ray diffraction and atomic absorption spectroscopy. Simple preparation of the catalyst from commercially available materials, high catalytic activity, simple operation, high yields, use of green solvents, easy magnetic separation and reusability of the catalyst with unaltered activity make our protocol a green and feasible synthetic strategy.
- Shiri, Lotfi,Ghorbani-Choghamarani, Arash,Kazemi, Mosstafa
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- Fe3O4 MNPs-DETA/Benzyl-Br3: A new magnetically reusable catalyst for the oxidative coupling of thiols
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We report a new strategy to immobilize a bromine source on the surface of magnetic Fe3O4 nanoparticles (Fe3O4 MNPs-DETA/Benzyl-Br3) leading to amagnetically recoverable catalyst, which exhibits high catalytic efficiency in oxidative coupling of thiols to the disulfides (89–98%). The Fe3O4 MNPs-DETA/Benzyl-Br3 catalyst was fabricated by anchoring 3-chloropropyltrimethoxysilane (CPTMS) onmagnetic Fe3O4 nanoparticles, followed with N-benzylation and reaction with bromine in tetrachloridecarbon. The resulting nanocomposite was analyzed by a series of characterization techniques such as FT-IR, SEM, TGA, VSM and XRD. The catalyst could be recovered viamagnetic attraction and could be recycled at least 5 times without appreciable decrease in activity.
- Shiri, Lotfi,Kazemi, Mosstafa
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p. 1171 - 1176
(2017/09/27)
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- Synthesis and characterization of tribenzyl ammonium-tribromide supported on magnetic Fe3O4 nanoparticles: a robust magnetically recoverable catalyst for the oxidative coupling of thiols and oxidation of sulfides
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Abstract: Taking into account the principles of green chemistry, magnetic nanoparticles, especially Fe3O4 nanoparticles, open up a new chapter in modern organic synthesis to inset a fascinating, stupendous and efficient catalytic strategy for facilitating catalyst recovery in various chemical reactions. Inspired by this topic, tribenzyl ammonium-tribromide immobilized on magnetic nanoparticles (Fe3O4–TBA-Br3) as a bromine source was successfully synthesized and its catalytic activity in the oxidative coupling of thiols and oxidation of sulfides was investigated. It is the first report on the use of the immobilized bromine source on Fe3O4 nanoparticles as a nanomagnetic recyclable catalyst for the oxidative coupling of thiols. The nanosolid catalyst could be easily recovered by a simple magnetic separation and reused for several cycles without significant degradation in catalytic activity. Graphical Abstract: [Figure not available: see fulltext.]
- Shiri, Lotfi,Ghorbani-Choghamarani, Arash,Kazemi, Mosstafa
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p. 2707 - 2724
(2017/04/18)
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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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- Efficient Generation of C–S Bonds via a By-Product-Promoted Selective Coupling of Alcohols, Organic Halides, and Thiourea
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A metal- and base-free three-component coupling of alcohols, heteroaryl halides, and thiourea has been developed for direct and selective synthesis of heteroaryl thioethers. This method can be easily scaled up to the gram scale and extended to dialkyl thioethers, heteroaryl selenides, benzothiazoles, and some antimycobacterially-active thioethers. Mechanistic studies revealed that a by-product-promoted in situ C–O activation of alcohols to more reactive alkyl halides and slow release of the thiol and alkyl halide intermediates are the key to the high selectivity and success of the reaction. (Figure presented.).
- Ma, Xiantao,Yu, Lei,Su, Chenliang,Yang, Yaqi,Li, Huan,Xu, Qing
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p. 1649 - 1655
(2017/05/29)
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- Efficient preparation of boehmite silica dopamine sulfamic acid as a novel nanostructured compound and its application as a catalyst in some organic reactions
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A novel type of recoverable boehmite nanocatalyst was prepared via immobilization of dopamine on the surface of boehmite followed by coating with silica and reacting with chlorosulfunic acid to obtain boehmite silica dopamine sulfamic acid (boehmite-Si-DSA). This compound was characterized by FT-IR spectroscopy, TGA, XRD, TEM and SEM techniques. Boehmite-Si-DSA was used as an efficient, recoverable and thermally stable heterogeneous nanocatalyst for the preparation of 2,3-dihydroquinazolin-4(1H)-one, sulfoxides and disulfides. The catalyst was recovered by simple filtration and reused several times without significant loss of catalytic efficiency.
- Hajjami, Maryam,Ghorbani-Choghamarani, Arash,Ghafouri-Nejad, Raziyeh,Tahmasbi, Bahman
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p. 3066 - 3074
(2016/05/09)
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- 3,6-Di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) mediated metal-free mild oxidation of thiols to disulfides in aqueous medium
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Thiols are efficiently oxidized to disulfides (RSSR) in the presence of 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) in aqueous medium, as well as in the absence of a solvent under mild and metal-free conditions. A broad range of alkyl, aryl and heterocyclic symmetrical disulfides can be easily obtained in almost quantitative yields. The X-ray single crystal structure of 2-aminocyclopent-1-ene-1-carbothioic dithioperoxyanhydride (disulfide obtained from 2-aminocyclopentene-1-dithiocarboxylic acid, ACDA) is reported. The reaction mechanism has been studied thoroughly. It is shown that the reaction proceeds through the formation of an organosulphur radical. Pytz interacts with thiol to accept one electron and produces an organosulphur radical. Pytz ultimately accepts two electrons to form H2pytz and is capable of oxidizing 2 equivalents of thiols.
- Samanta, Suvendu,Ray, Shounak,Ghosh, Abhisek Brata,Biswas, Papu
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p. 39356 - 39363
(2016/06/01)
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- Visible-light-mediated facile synthesis of disulfides using reusable TiO2/MoS2nanocomposite photocatalyst
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A nontoxic and inexpensive TiO2/MoS2nanocomposite was prepared and employed as an efficient photocatalyst for the synthesis of symmetrical disulfides under visible light irradiation at room temperature. Both aryl and alkyl thiols survived the reaction conditions, affording the corresponding disulfides in good to excellent yields. The photocatalyst could be easily recovered by simple centrifugation and filtration and reused several times without significant loss in its activity.
- Liu, Wenjie,Wang, Cancan,Huang, Yibo,Chen, Qun,Wang, Liang,He, Mingyang
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supporting information
p. 1268 - 1274
(2016/08/16)
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- Synthesis and characterization of Co (II) and Fe (III) Schiff base complexes grafted onto mesoporous MCM-41: A heterogeneous and recyclable nanocatalysts for the selective oxidation of sulfides and oxidative coupling of thiols
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Novel organic–inorganic hybrid heterogeneous catalysts containing cobalt(II) and iron(III) Schiff base complexes, grafted on the internal surface of MCM-41 pores were prepared by introducing a metal salt into a mesoporous silica functionalized with a Schiff base ligand. The chemical and physical properties of the catalysts were investigated by BET, TGA, XRD, FT-IR, and TEM techniques. These complexes were found to be efficient, selective catalysts for the oxidation of various sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides with urea hydrogen peroxide in excellent yield at room temperature. The designed catalytic system prevents effectively the overoxidation of sulfides and thiols to sulfoxides and sulfones, respectively. Also the heterogeneous catalysts can be recovered easily and reused many times without significant loss of activity and selectivity.
- Noori, Nourolah,Nikoorazm, Mohsen,Ghorbani-Choghamarani, Arash
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p. 1388 - 1395
(2016/09/28)
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- Synthesis, characterization, and catalytic application of Cr and Mn Schiff base complexes immobilized on modified nanoporous MCM-41
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Immobilization of chromium and manganese Schiff base complexes by postgrafting of ligand then metal salts on the walls of mesoporous MCM-41 functionalized with (3-aminopropyl)triethoxysilane is described. Characterization of the resulting heterogeneous catalysts by Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, and Brunauer–Emmett–Teller (BET) techniques indicated successful grafting of these two complexes inside the nanochannels of MCM-41. The complexes were found to be efficient, selective catalysts for oxidation of various sulfides to sulfoxides and oxidative coupling of thiols to corresponding disulfides using H2O2 as oxidant at room temperature. The recycling results of these heterogeneous catalysts showed good recyclability without significant loss of activity or selectivity in successive runs, indicating that the Cr and Mn Schiff base complexes supported on nanoporous MCM-41 remained intact and the coordination environments were not altered during the reaction.
- Nikoorazm, Mohsen,Ghorbani-Choghamarani, Arash,Noori, Nourolah
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p. 4621 - 4640
(2016/07/06)
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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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- 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 0044; 0045; 0046; 0048; 0105; 0106; 0107; 0108
(2016/10/07)
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- Nickel Schiff-base complexes immobilized on boehmite nanoparticles and their application in the oxidation of sulfides and oxidative coupling of thiols as novel and reusable nano organometal catalysts
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Boehmite nanoparticles were prepared by very simple and inexpensive procedure in water at room temperature using commercially available materials. Two Schiff-base complexes of nickel have been immobilized on the boehmite nanoparticles. These catalysts were characterized by FT-IR spectroscopy, TGA, XRD, BET, UV-DRS, TEM, SEM, EDS and ICP-OES techniques. These compounds were applied as catalysts for the oxidation of sulfides to sulfoxides and oxidative coupling of thiols to disulfides under mild reaction conditions at room temperature. These catalysts were recovered by simple filtration and reused several times without significant loss of their catalytic efficiency.
- Ghorbani-Choghamarani, Arash,Tahmasbi, Bahman,Arghand, Fatemeh,Faryadi, Sara
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p. 92174 - 92183
(2015/11/17)
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- Oxo-vanadium(IV) Schiff base complex supported on modified MCM-41: A reusable and efficient catalyst for the oxidation of sulfides and oxidative S-S coupling of thiols
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Oxo-vanadium(IV) Schiff base complex supported on MCM-41 as an organic-inorganic hybrid heterogeneous catalyst was synthesized with post-grafting of MCM-41 with 3-aminoropropyltrimethoxysilane and subsequent reaction with 3,4-dihydroxybenzaldehyde and then complexation with oxo-vanadium acetylacetonate salt. The catalyst was analysed using a series of characterization techniques such as Fourier transform infrared spectroscopy, small-angle X-ray diffraction, nitrogen absorption isotherm, transmission electron microscopy and thermogravimetric analysis. The data collected provided evidence that the vanadium complex was anchored onto MCM-41. High catalytic activity of this catalyst was observed in the oxidation of various sulfides and thiols (into sulfoxides and disulfides, respectively) with urea hydrogen peroxide as oxidant in high to excellent yields and selectivity under mild conditions. The heterogeneous catalyst could be recovered easily and reused several times without significant loss in catalytic activity and selectivity.
- Nikoorazm, Mohsen,Ghorbani-Choghamarani, Arash,Noori, Nourolah
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p. 328 - 333
(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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- Bovine serum albumin triggered waste-free aerobic oxidative coupling of thiols into disulphides on water: An extended synthesis of bioactive dithiobis(phenylene)bis(benzylideneimine) via sequential oxidative coupling-condensation reactions in one pot from aminothiophenol and benzaldehyde
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Bovine serum albumin (BSA) has been explored for aerobic oxidative coupling of thiols (aromatic, heterocyclic as well as aliphatic) "on water" towards formation of disulphides (SS) without using any metal/non-metal complexes, bases and additives, which renders the process environmentally benign and economically attractive with good recyclability (up to four cycles). The developed green protocol was further extended for synthesis of diallyldisulphide (DADS), an important constituent of natural occurring allicin. Among various synthesized disulphides, bis(2-aminophenyl)disulphide, obtained by oxidative coupling of 2-aminothiophenol in BSA, was further utilized for condensation with benzaldehyde in the same pot thus enabling easy access to bioactive dithiobis(phenylene)bis(benzyldeneimine). This is the first example of BSA catalysed sequential (oxidation/condensation) reaction where one SS and two CN bonds are formed solely "on water."
- Saima,Lavekar, Aditya G.,Kumar, Rajesh,Sinha, Arun K.
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p. 113 - 123
(2015/04/14)
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- Photoinduced heterodisulfide metathesis for reagent-free synthesis of polymer nanoparticles
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Reagent-free synthetic methods are of great interest because of their simplicity and implications in green chemistry. We have taken advantage of photoinduced heterodisulfide metathesis to generate crosslinked polymer nanoparticles. The method of development and the mechanistic basis for the synthetic approach are outlined in this communication.
- Li, Longyu,Song, Cunfeng,Jennings, Matthew,Thayumanavan
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p. 1425 - 1428
(2015/08/03)
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- Simple and efficient oxidative transformation of thiols to disulfides using Cu(NO3)2·3H2O in H2O/AcOEt
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A simple and efficient methodology is described for the preparation of symmetric disulfides from corresponding thiols in the presence of Cu(NO 3)2 and in H2O/AcOEt (1:2). This process is environmentally friendly and economical because it does not use toxic or expensive reagents.
- Soleiman-Beigi, Mohammad,Taherinia, Zahra
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p. 1151 - 1154
(2014/06/24)
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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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- Flavin-catalyzed aerobic oxidation of sulfides and thiols with formic acid/triethylamine
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An efficient and practical catalytic method for the aerobic oxidative transformation of sulfides into sulfoxides, and thiols into disulfides with formic acid/TEA in the presence of a new, readily available, and stable flavin catalyst 5d is described. This journal is the Partner Organisations 2014.
- Murahashi, Shun-Ichi,Zhang, Dazhi,Iida, Hiroki,Miyawaki, Toshio,Uenaka, Masaaki,Murano, Kenji,Meguro, Kanji
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supporting information
p. 10295 - 10298
(2014/08/18)
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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
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supporting information
p. 5514 - 5522
(2013/11/06)
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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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- 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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- Supported iron oxide nanoparticles: Recoverable and efficient catalyst for oxidative S-S coupling of thiols to disulfides
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Supported iron oxide nanoparticles are found to be efficient and recoverable catalyst in the selective oxidation of thiols to their corresponding disulfides using hydrogen peroxide as green oxidant at room temperature. The protocol features an easy work-up, simplicity and the utilizing mild reaction conditions, as well as high selectivity toward disulfides, are highly advantageous compared to alternative reported methodologies. The supported iron oxide nanoparticles could be easily recovered and reused several times without any loss of activity. ICP-MS results prove that there is no metal leaching observed, and demonstrating the stability of the catalyst under the reaction conditions.
- Rajabi, Fatemeh,Kakeshpour, Tayeb,Saidi, Mohammad Reza
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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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- Synthesis of disulfides by laccase-catalyzed oxidative coupling of heterocyclic thiols
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A new method employing a laccase-mediator system as the catalyst and aerial oxygen as the oxidant has been developed for the oxidative coupling of heterocyclic thiols to the corresponding disulfides with yields up to 95% under mild reaction conditions.
- Abdel-Mohsen, Heba T.,Sudheendran, Kavitha,Conrad, Juergen,Beifuss, Uwe
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supporting information
p. 1490 - 1495
(2013/09/24)
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