- Selenium-linked liquid crystal dimers for twist-bend nematogens
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The recently discovered twist-bend nematic (NTB) phase has become an intensively studied topic in supramolecular chemistry and condensed matter science. Herein, a new molecular design for twist-bend nematogens employing the selenoether (C–Se–C) linkage, instead of the conventional methylene or ether linkages, is introduced. We synthesized CBSenSeCB dimers, consisting of two cyanobiphenyl (CB) units connected by two selenoether linkers sandwiching an odd-numbered alkylene spacer (n = 3, 5, 7, and 9) and revealed their phase transitions and mesomorphism. CBSenSeCB (n = 5, 7, and 9) can potentially form mesophases; notably, CBSe7SeCB formed the NTB phase from the conventional uniaxial nematic phase, which was cooled to below room temperature. The structure of the all-trans model of CBSe7SeCB, optimized by the density functional theory, suggests that the molecular bend angle between the para axes of the cyanobiphenyl moieties is ~90°, which is more bent than those of previously reported twist-bend nematogens. Such a keen curvature is ascribed to the small C–Se–C angle of ~101°. In addition, the molecular bend angles of the twist-bend dimers, including the present and previously reported ones, correlate linearly with their phase-transition temperatures. The present study paves the way for the molecular design of new twist-bend nematic liquid crystals based on chalcogen linkages.
- Arakawa, Yuki,Tsuji, Hideto
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Read Online
- Enhancing the Potential of Miniature-Scale DNA-Compatible Radical Reactions via an Electron Donor-Acceptor Complex and a Reversible Adsorption to Solid Support Strategy
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DNA-encoded library (DEL) technology is a powerful tool in the discovery of bioactive probe molecules and drug leads. Mostly, the success in DEL technology stems from the molecular diversity of the chemical libraries. However, the construction of DELs has been restricted by the idiosyncratic needs and the required low concentration (~1 mM or less) of the library intermediate. Here, we report visible-light-promoted on-DNA radical coupling reactions via an electron donor-acceptor (EDA) complex and a reversible adsorption to solid support (RASS) strategy. This protocol provides a unique solution to the challenges of increasing the reactivity of highly diluted DNA substrates and reducing the residues of heavy metals from photocatalysts. A series of on-DNA indole sulfone and selenide derivatives were obtained with good to quantitative conversions. It is anticipated that these mild-condition on-DNA radical reactions will significantly improve the chemical diversity of DELs and find widespread utility to DEL construction.
- Lin, Bizhen,Lu, Weiwei,Chen, Zhen-Yu,Zhang, Yue,Duan, Yin-Zhe,Lu, Xiaojie,Yan, Ming,Zhang, Xue-Jing
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supporting information
p. 7381 - 7385
(2021/10/12)
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- Synthesis of Seleno Oxindoles via Electrochemical Cyclization of N-arylacrylamides with Diorganyl Diselenides
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The tandem cyclization of acrylamide with diselenides facilitated by electrochemical oxidation was successfully developed. This strategy provided an environmentally friendly method for the construction of C?Se bond. A series of seleno oxindoles with pharmacological activity were obtained by using this well-designed tandem cyclization strategy. The in vitro antitumor activity of the compounds was also screened through MTT assay. Results showed that the seleno oxindoles exhibited better antitumor activity than other oxindole derivatives. (Figure presented.).
- Wang, Xin-Yu,Zhong, Yuan-Fang,Mo, Zu-Yu,Wu, Shi-Hong,Xu, Yan-Li,Tang, Hai-Tao,Pan, Ying-Ming
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p. 208 - 214
(2020/12/04)
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- Blue light-promoted radical sulfoximido-chalcogenization of aliphatic and aromatic alkenes
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A transition metal-free synthesis ofN-(arylthio/seleno)ethyl sulfoxidminesviablue light-promoted radical sulfoximido-chalcogenization of aliphatic and aromatic alkenes was developed. The sulfoximidation process demonstrated high chemoselectivity and allowed a broad substrate scope, completing the sulfoximido-chalcogenization of alkenes in good yields.
- Chen, Hongyi,Chen, Li,He, Ze,Zeng, Qingle
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supporting information
p. 2624 - 2627
(2021/04/21)
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- Highly selective radical isothiocyano-chalcogenization of alkenes with NH4SCN in water
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In the presence of catalytic amounts of molecular iodine and stoichiometric potassium persulfate, a green, highly chemoselective, regioselective and cis-selective radical isothiocyano-chalcogenization of alkenes with NH4SCN in water is disclosed. This three component reaction features high selectivities, an environmentally benign process, mild conditions, high yields, excellent functional-group tolerance, and broad substrate scope. The resulting products can be further transformed into other molecules with structural similarities of these compounds to bioactive analogs.
- He, Ze,Kang, Xiaokang,Xu, Chao,Zeng, Qingle
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supporting information
p. 7544 - 7548
(2021/10/12)
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- FeCl3-catalyzed three-component aryl-selenylation of alkenes
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FeCl3-catalyzed three-component aryl-selenylation of alkenes with good to excellent yields has been disclosed. This method is characterized by synthesis of complicated products in a single-step reaction, simple operation and readily available commercially reagents. Finally, a reasonable mechanism of FeCl3-catalyzed aryl-selenylation is proposed.
- Xu, Chao,He, Ze,Yang, Hongqin,Chen, Hongyi,Zeng, Qingle
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- Visible-light-driven radical 1,3-addition of selenosulfonates to vinyldiazo compounds
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Herein, we report a visible-light-driven radical 1,3-selenosulfonylation of vinyldiazo compounds with selenosulfonates, providing various γ-seleno allylic sulfones in good yields. This photochemical reaction was carried out at room temperature in an open flask using ethyl acetate as the solvent without any photocatalysts or additives. The control experiments corroborated that the 1,3-addition proceeded via a radical-chain propagation process. The synthetic applications of the resulting products were demonstrated by deselenization, reduction, bromination and allylation.
- Li, Weiyu,Zhou, Lei
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supporting information
p. 6652 - 6658
(2021/09/10)
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- Iodine mediated synthesis of diaryl diselenides using SeO2 as a selenium source
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A simple, eco-friendly and convenient procedure has been developed for the synthesis of diphenyl diselinides from readily available aryl boronic acids by reaction with SeO2 in the presence of iodine under simple conditions. The methodology is reported about 19 examples and applicable to a broad scope of aryl boronic acids containing electron-rich and electron-poor substituents. Apart from being milder and environmentally benign conditions, this synthetic protocol comprises a novel, reliable methodology to give good to high yields of the desired diaryl diselenides.
- Kommula, Dileep,Li, Qing,Ning, Siyang,Liu, Wujun,Wang, Qian,Zhao, Zongbao K.
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supporting information
p. 1026 - 1034
(2020/03/04)
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- Rhodium-Catalyzed Enantioselective Hydroselenation of Heterobicyclic Alkenes
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A highly efficient Rh(I)/(S)-xyl-Binap catalytic system is developed for the asymmetric hydroselenation of various nonpolar olefins with diselenides. Under these mild reaction conditions, a wide range of heterobicyclic alkenes give selenol-incorporated adducts in excellent enantioselectivities (up to 97%) along with high yields (up to 96%) by overcoming self-promoted racemic hydroselenation. The strategy is also applied for kinetic resolution of unsymmetric oxabenzonorbornadiene.
- Li, Sifeng,Yang, Qingjing,Bian, Zhaoxiang,Wang, Jun
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supporting information
p. 2781 - 2785
(2020/03/30)
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- Continuous Electrochemical Synthesis of Iso-Coumarin Derivatives from o-(1-Alkynyl) Benzoates under Metal- and Oxidant-Free
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A non-oxidant and metal-free strategy for synthesizing iso-coumarin by using a continuous electrochemical microreactor to initiate an oxidative cyclization reaction of o-(1-alkynyl) benzoate and radicals. This efficient and clean continuous electrosynthesis method not only avoids the complicated gas protection operation and production of by-products in the batch processes, but also help to overcome the difficulty that batch metal catalysis and electrocatalysis are difficult to scale up, and has the potential for pilot-scale experiment.
- Lin, Xinxin,Fang, Zheng,Zeng, Cuilian,Zhu, Chenlong,Pang, Xinyan,Liu, Chengkou,He, Wei,Duan, Jindian,Qin, Ning,Guo, Kai
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supporting information
p. 13738 - 13742
(2020/10/02)
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- Transition metal-free coupling reactions of benzylic trimethylammonium salts with di(hetero)aryl disulfides and diselenides
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A new protocol was developed to synthesize (enantioenriched) thioethers and selenoethers from (chiral) benzylic trimethylammonium salts and di(hetero)aryl disulfides or diselenides. These syntheses were promoted by the presence of weak base and did not require the use of any transition metal, and resulted in the target products with good to excellent yields (72-94%). Using quaternary ammonium salts synthesized from enantiomerically enriched amines led to highly enantiopure benzylic thioethers and selenoethers (94-99% ee) with configurations reversed from those of their enantioenriched quaternary ammonium salts. This journal is
- Li, Fuhai,Wang, Dan,Chen, Hongyi,He, Ze,Zhou, Lihong,Zeng, Qingle
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supporting information
p. 13029 - 13032
(2020/11/07)
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- Metal-Free ipso -Selenocyanation of Arylboronic Acids Using Malononitrile and Selenium Dioxide
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The first ipso -selenocyanation of arylboronic acids is achieved using selenium dioxide and malononitrile under mild conditions. The reaction is successful even without metal or base in DMSO. The major advantages of this new method are an easy set-up, excellent yields, and the use of odorless and inexpensive selenium reagents. Basic conditions subsequently afford new access to diaryldiselenides in good yields without isolating the organoselenocyanate intermediates.
- Broggi, Julie,Kosso, Anne Roly Obah,Redon, Sébastien,Vanelle, Patrice
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supporting information
p. 3758 - 3764
(2019/09/30)
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- In situ synthesis of CuO nanoparticles over functionalized mesoporous silica and their application in catalytic syntheses of symmetrical diselenides
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A versatile and novel catalyst, CuO nanoparticles immobilized over functionalized mesoporous silica (nCuO-FMS), has been synthesized over an organically modified mesoporous silica framework following a facile synthetic route. The surface of the silica support (SBA-15) is first grafted with the 3-aminopropyl silane group and then further functionalized with tris(4-formylphenyl)amine. The reaction is performed in such a way that a few -CHO groups remain free for further functionalization. Finally, the CuO nanoparticles immobilized on mesoporous silica are obtained by a one pot reaction between the functionalized silica, 2-aminophenol and CuCl2. The product obtained has been used as a catalyst for the syntheses of symmetrical diselenides in the presence of KOH as the base and dimethyl sulphoxide (DMSO) as the solvent. The materials have been characterized thoroughly by X-ray powder diffraction, nitrogen adsorption-desorption studies, transmission electron microscopy, thermal analysis and different spectroscopic techniques. The Cu content of the sample has been determined by atomic absorption spectrophotometry (AAS). The products of the catalytic studies have been identified and estimated by NMR spectroscopy. Almost 78% isolated yield could be achieved at 363 K within 3 hours of the reaction and the catalyst, nCuO-FMS, can be recycled at least up to five catalytic cycles.
- Das, Trisha,Chatterjee, Rana,Majee, Adinath,Uyama, Hiroshi,Morgan, David,Nandi, Mahasweta
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p. 17874 - 17886
(2019/12/24)
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- Synthesis of 3-Organoselenyl-2H-Coumarins from Propargylic Aryl Ethers via Oxidative Radical Cyclization
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A metal-free oxidative radical cyclization/selenylation of propargylic aryl ethers with diaryl diselenides was developed. This protocol provided an alternative method to synthesize 3-organoselenyl-2H-coumarins via the formation of C?Se bond, C?C bond, and C=O bond in one step. Moreover, a broad range of functional groups (such as halogen, aldehyde, ketone, cyano, and nitro group) were tolerated. (Figure presented.).
- Fang, Jun-Dan,Yan, Xiao-Biao,Zhou, Li,Wang, Yu-Zhao,Liu, Xue-Yuan
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supporting information
p. 1985 - 1990
(2019/03/13)
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- Catalyst-free gem-difunctionalization of fluoroalkyl-substituted diazo compound with diselenide or disulfide and NFSI
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The gem-difunctionalization of fluoroalkyl-substituted diazo compounds by utilizing diselenides or disulfides and NFSI under catalyst-free and mild conditions is reported. A series of gem-aminoselenolation and gem-aminosulfonylation products bearing fluoroalkyl substituents were obtained in high to excellent yields. Different types of conjugated diazo compounds are also applicable to this transformation. Preliminary mechanistic studies indicate that a selenoimidate intermediate generated from diselenide and NFSI is involved for this transformation.
- Li, Jiuling,Ma, Chaoqun,Xing, Dong,Hu, Wenhao
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supporting information
p. 2101 - 2105
(2019/03/29)
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- Atom Transfer Oxidative Radical Cascade of Aryl Alkynoates towards 1,1-Dichalcogenide Olefins
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An oxidative trifunctionalization of aryl alkynoates has been devised via the chalcogenide radical triggered intramolecular 1,4-aryl migration/decarboxylation cascade to prepare 1,1-dichalcogenide tetrasubstituted alkenes in high yields (up to 98 %). This operationally simple reaction proceeds under metal-free conditions, can be executed on gram scale, and highlights formal 1,1-difunctionalization of alkynes. Synthetic potential of this protocol was demonstrated through a twofold cascade rearrangement to access highly conjugated tetra-selenylated alkenes along with a cross-dehydrogenative annulation to prepare fluorene derivative.
- Sahoo, Harekrishna,Ramakrishna, Isai,Mandal, Anup,Baidya, Mahiuddin
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supporting information
p. 4549 - 4552
(2019/07/31)
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- Iron(III)-catalyzed synthesis of selenoesters from α-amino carbonyl derivatives at room temperature
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An Fe(III)-catalyzed efficient method has been developed for the synthesis of selenoester derivatives in high yields through the coupling of α-amino carbonyl/glycine derivatives and diselenides under ambient air. A library of benzoselenoate derivatives having a variety of substituents has been synthesized. A plausible reaction pathway has been predicted. Experimental results suggest that the reaction proceeds through a radical pathway. Operational simplicity, compatibility with various α-amino carbonyls and diselenides, high yields, fast reaction and mild reaction conditions are the notable advantages of this procedure. We have also shown the practical application of the synthesized selenoesters which is useful to generate peptide bonds in biological sciences.
- Chatterjee, Rana,Mukherjee, Anindita,Santra, Sougata,Zyryanov, Grigory V.,Majee, Adinath
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- Three-Component Aminoselenation of Arynes
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The three-component coupling of tertiary amines, arynes, and aryl selenium bromide or diaryl diselenide as an electrophilic selenium source allowing the synthesis of 2-selanyl aniline derivatives is reported. This aminoselenation reaction of arynes installs a C-N and C-Se bond under mild conditions, and the products are formed in moderate to good yields. This reaction is compatible with various functional groups, and the preliminary studies on the mechanism of the reaction is also provided.
- Gaykar, Rahul N.,Guin, Avishek,Bhattacharjee, Subrata,Biju, Akkattu T.
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supporting information
p. 9613 - 9617
(2019/11/28)
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- CuO nanoparticles-catalyzed a novel method to the synthesis of symmetrical diselenides from aryl halides: selenoamide as an organic Se-donor reagent
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A new method is reported for the synthesis of symmetrical diaryldiselenides from aryl halides using selenoamide as an organic Se-donor reagent in the presence of copper (II) oxide nanoparticles. CuO nanoparticles were found to be an efficient and inexpensive catalyst for ligand-free C-Se bond formation with a series of symmetrical diaryldiselenides obtained in good to excellent yield.
- Soleiman-Beigi, Mohammad,Yavari, Issa,Sadeghizadeh, Fatemeh
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p. 2239 - 2246
(2018/08/04)
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- Asymmetric Heteroleptic Ir(III) Phosphorescent Complexes with Aromatic Selenide and Selenophene Groups: Synthesis and Photophysical, Electrochemical, and Electrophosphorescent Behaviors
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With the aim of evaluating the potential of selenium-containing groups in developing electroluminescent (EL) materials, a series of asymmetric heteroleptic Ir(III) phosphorescent complexes (Ir-Se0F, Ir-Se1F, Ir-Se2F, and Ir-Se3F) have been synthesized by using 2-selenophenylpyridine and one ppy-type (ppy = 2-phenylpyridine) ligand with a fluorinated selenide group. To the best of our knowledge, these complexes represent unprecedented examples of asymmetric heteroleptic Ir(III) phosphorescent emitters bearing selenium-containing groups. Natural transition orbital (NTO) analysis based on optimized geometries of the first triplet state (T1) have shown that the phosphorescent emissions of these Ir(III) complexes dominantly show 3π- π? features of the 2-selenophenylpyridine ligand with slight metal to ligand charge transfer (MLCT) contribution. In comparison with their symmetric parent complex Ir-Se with two 2-selenophenylpyridine ligands, these asymmetric heteroleptic Ir(III) phosphorescent complexes can show much higher phosphorescent quantum yields (φP) of ca. 0.90. Both the hole- and electron-trapping ability of these Ir(III) phosphorescent complexes can be enhanced by selenophene and fluorinated selenide groups to improve their EL efficiencies. The EL abilities of these asymmetric heteroleptic Ir(III) phosphorescent emitters fall in the order Ir-Se3F > Ir-Se2F > Ir-Se1F > Ir-Se0F. The highest EL efficiencies have been achieved by Ir-Se3F in the solution-processed OLEDs with external quantum efficiency (next), current efficiency (n L), and power efficiency (n P) of 19.9%, 65.6 cd A-1, and 57.3 lm W-1, respectively. These encouraging EL results clearly indicate the great potential of selenium-containing groups in developing high-performance Ir(III) phosphorescent emitters.
- Feng, Zhao,Wang, Dezhi,Yang, Xiaolong,Jin, Deyuan,Zhong, Daokun,Liu, Boao,Zhou, Guijiang,Ma, Miaofeng,Wu, Zhaoxin
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p. 11027 - 11043
(2018/09/14)
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- Design, Synthesis, and Biological Evaluation of Novel Selenium-Containing Isocombretastatins and Phenstatins as Antitumor Agents
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Two series of structurally related organoselenium compounds designed by fusing the anticancer agent methyl(phenyl)selane into the tubulin polymerization inhibitors isocombretastatins or phenstatins were synthesized and evaluated for antiproliferative acti
- Pang, Yanqing,An, Baijiao,Lou, Lanlan,Zhang, Junsheng,Yan, Jun,Huang, Ling,Li, Xingshu,Yin, Sheng
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p. 7300 - 7314
(2017/09/22)
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- Regioselective Synthesis of Selenide Ethers through a Decarboxylative Coupling Reaction
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An efficient and selective approach to the synthesis of selenide ethers containing one or two geminal C–Se bonds from readily available diselenides and phenylacetic acids was developed. Compounds containing one C–Se bond were prepared by employing air as the oxidant under metal-free conditions, whereas compounds having two geminal C–Se bonds were formed via the iron(III) chloride/oxygen/cesium carbonate (FeCl3/O2/Cs2CO3) system. Moreover, 1,2-diphenyldisulfane also could be smoothly converted into the corresponding sulfur ether product under the standard reaction conditions. (Figure presented.).
- Cui, Fei-Hu,Chen, Jing,Su, Shi-Xia,Xu, Yan-Li,Wang, Heng-Shan,Pan, Ying-Ming
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p. 3950 - 3961
(2017/11/20)
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- The direct synthesis of symmetrical disulfides and diselenides by metal-organic framework MOF-199 as an efficient heterogenous catalyst
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A highly crystalline porous copper-based metal-organic framework MOF-199 was synthesized, and characterized by several techniques, including XRD, EDX, SEM, and FT-IR. MOF-199 was used as an efficient catalyst for the one-pot and efficient synthesis of organic dichalcogenides from aryl halides (-OTs) and elemental sulfur and selenium in polyethylene glycols (PEGs). A variety of disulfides and diselenides can be obtained in good to excellent yields of up to 98% in a relatively short reaction time.
- Soleiman-Beigi, Mohammad,Yavari, Issa,Sadeghizadeh, Fatemeh
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p. 87564 - 87570
(2015/11/09)
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- Iron-catalyzed formation of C-Se and C-Te bonds through cross coupling of aryl halides with Se(0) and Te(0)/nano-Fe3O4@GO
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The formation of C-Se and C-Te bonds is of synthetic and biological importance. Graphene oxide based nano-Fe3O4 (nano-Fe 3O4@GO) is used as a reusable catalyst for the efficient synthesis of diselenides and ditellurides, through cross coupling of Se(0) or Te(0) with aryl iodides. The magnetic heterogeneous catalyst could be easily recovered and reused many times without significant loss of catalytic activity. In addition the superiority of nano-Fe3O4@GO over pristine nano-Fe3O4 is established. Georg Thieme Verlag Stuttgart. New York.
- Kassaee, Mohammadzaman,Motamedi, Elaheh,Movassagh, Barahman,Poursadeghi, Samira
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p. 2337 - 2342
(2013/09/02)
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- Copper-catalyzed chalcogenation of aryl iodides via reduction of chalcogen elements by aluminum or magnesium
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Aluminum-induced copper-catalyzed coupling of aryl iodides with selenium or sulfur element could afford the corresponding diaryl selenides or sulfides in good yields. When magnesium chloride as an additive was employed, diaryl monoselenides and monosulfides were selectively obtained. On the contrary, the use of sodium carbonate produced diaryl diselenides and disulfides. The preparation of diaryl diselenides was necessary for magnesium as a reductant. Regrettably, tellurium was very low reactivity.
- Taniguchi, Nobukazu
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p. 10510 - 10515,6
(2012/12/12)
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- Microwave-assisted one-pot synthesis of symmetrical diselenides, ditellurides and disulfides from organoyl iodides and elemental chalcogen catalyzed by CuO nanoparticles
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In this study CuO nanoparticles were applied as a catalyst for CSe, CTe, and CS bond formation. The reaction was performed with organoyl iodides and elemental selenium, tellurium or sulfur under microwave irradiation in the presence of a base and solvent at 80 °C. This novel protocol allowed the synthesis of a variety of diselenides, ditellurides and disulfides in good to excellent yields in a very short reaction time.
- Botteselle, Giancarlo V.,Godoi, Marcelo,Galetto, Fabio Z.,Bettanin, Luana,Singh, Devender,Rodrigues, Oscar E.D.,Braga, Antonio L.
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p. 186 - 193
(2013/01/14)
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- Electrophilic organic selenium reagents - Protonated seleninic acids as precursors for unsymmetrical aromatic selenides
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Arylselenylations of methylbenzenes, methoxybenzenes and thiophene were smoothly achieved with selenenium ions generated by comproportionation of 1:1 mixtures of p-toluenesulfonic acid salts of seleninic acids and the corresponding diselenides. A series of p-toluenesulfonic salts of seleninic acids were prepared by hydrogen peroxide oxidation of the corresponding diselenides in the presence of p-toluenesulfonic acid. Novel 2-(organylseleno)thiophenes were obtained by heating the protonated seleninic acids with a 50-fold excess of thiophene in glacial acetic acid.
- Stuhr-Hansen, Nicolai,S?lling, Theis Ivan,Henriksen, Lars
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scheme or table
p. 2633 - 2643
(2011/04/25)
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- An efficient one-pot synthesis of symmetrical diselenides or ditellurides from halides with CuO nanopowder/Se0 or Te0/base
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(Equation Presented). A CuO nanopowder-catalyzed coupling reaction of aryl, alkyl, and heteroaryl iodides with elemental selenium and tellurium takes place in the presence of KOH at 90 °C in DMSO. A wide range of substituted symmetrical diselenides and ditellurides were afforded with good to excellent yields.
- Singh, Devender,Deobald, Anna M.,Camargo, Leandro R.S.,Tabarelli, Greice,Rodrigues, Oscar E.D.,Braga, Antonio L.
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supporting information; experimental part
p. 3288 - 3291
(2010/09/30)
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- A facile route to phenyl, phenylsulfanyl and phenylselanyl substituted pyrano[3,2-c]chromenes
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The synthesis of phenyl, phenylsulfanyl and phenylselanyl substituted pyrano[3,2-c]chromenes 4 is accomplished via cyclocondensation of 4-oxo-4H-chromen-3-carbaldehydes 1 with appropriately substituted acetic acids 2 under mild conditions. Further treatment of 4 with alcohol or water led to 5-alkoxy- and 5-hydroxy-2H,5H-pyrano[3,2-c]chromen-2-ones 5 and 6, respectively. Acid and thermal catalysed rearrangement of 4-6 gave 5-hydroxypyrano[2,3-b]chromen-2(10aH)-ones 7 and their subsequent substitution led to 5-alkoxyderivatives 8. Reaction of 4 with amides led to 5-acylamino or 5-phenylsulfonamino substituted 2H,5H-pyrano[3,2-c]chromen-2-ones 9. Reactions were performed under heating or microwave irradiation.
- Lácová, Margita,Ga?parová, Renata,Koi?, Pavol,Bohá?, Andrej,El-Shaaer, Hafez M.
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experimental part
p. 1410 - 1419
(2010/04/04)
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- Preparation of diselenides by the oxidation of selenols using trichloroisocyanuric acid
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Selenols are readily oxidized to diselenides by a solution of pyridine, water, benzoic acid, and trichloroisocyanuric acid in acetonitrile and methylene chloride.
- Zhong,Guo
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p. 1507 - 1510
(2007/10/03)
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- Samarium diiodide-induced reduction of amorphous selenium: A facile synthesis of diaryl diselenides
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Samarium diiodide reduces amorphous selenium to Se2/2- in THF. Subsequent addition of aryldiazonium fluoborates affords diaryl diselenides in moderate to good yields.
- Zhang,Jia,Zhou
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p. 1247 - 1252
(2007/10/02)
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- A convenient new method for the preparation of diaryl diselenide
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Diaryliodonium salts react with sodium O, O-diethyl phosphoroselenoate in ethano-DMF at 70-80°C then hydrolyzed in basic medium and oxidized at room temperature to afford symmetric diaryl diselenides in better yields.
- Liu,Chen
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p. 2673 - 2676
(2007/10/02)
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- Improved Synthesis of Aromatic Diselenides
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The reaction of aromatic and heterocyclic lithio derivatives with elemental selenium, followed by dimethylthiocarbamyl chloride, gives highly crystalline and readily purified Se-aryl N,N-dimethylselenothiocarbamates.Alkaline hydrolysis of the latter, followed by ferricyanide oxidation, affords diselenides.Overall yields and purity of the diselenides are superior to those obtained by the standard direct selenation-oxidation method.
- Jen, Kwan-Yue,Cava, Michael P.
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p. 1449 - 1451
(2007/10/02)
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- Reaction of Areneselenyl Chlorides and alkenes. An example of Nucleophilic Displacement at Bivalent Selenium
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The effect of substituents in the phenyl ring of both the electrophile and the alkene has been studied in the reaction of areneselenyl chlorides and (E)- and (Z)-1-phenylpropenes.Electron-donating groups in both phenyl rings enhance the rate of reaction.Viewing this reaction as a nucleophilic displacement at bivalent selenium leads to a model that allows the possibility of reaction by a continuum of mechanisms.These mechanisms differ only in the relative amounts of C-Se bond making and Se-Cl bond breaking in the rate-determining transition state.From our data, it is concluded that C-Se bond making lags behind Se-Cl bond breaking in the rate determining transition state.
- Schmid, George H.,Garratt, Dennis G.
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p. 4169 - 4172
(2007/10/02)
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