- Aromatic Substitution and Dealkylation by Alkanetellurolate Anions
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Under the action of alkanetellurolate anion phenyl halides undergo aromatic substitution followed by dealkylation of the alkyl phenyl telluride thus formed.The generated benzenetellurolate anion can be either alkylated or oxidized to diphenyl ditelluride, or added to acetylene.Butyl methyl telluride and selenide are demethylated by methanechalcogenolate anions.
- Potapov, V. A.,Amosova, S. V.,Petrov, P. A.
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- Oxidative addition of diphenyldichalcogenides PhEEPh (E = S, Se, Te) to low-valent CN-and NCN-chelated organoantimony and organobismuth compounds
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The reactions of the organoantimony(I) compound L1 4Sb4 (1) (where L1 = [o-C6H 4(CH=NC6H3(i-Pr)2-2,6)]) with diphenyldichalcogenides PhEEPh (E = S, Se, or Te) gave compounds L 1Sb(EPh)2 (E = S (2), Se (3), Te (4)) as the result of the oxidative addition of the antimony(I) atom across the chalcogen-chalcogen bond. The reaction of diphenyldichalcogenides PhEEPh with an in situ prepared organobismuth(I) compound (via reaction of the parent chloride L 1BiCl2 (5) with two equivalents of K[B(s-Bu) 3H]) gave surprisingly diorganobismuth compounds L1 2Bi(EPh) (E = S (6), Se (7), Te (8)) as the major products along with only a trace amount of the intended compounds L1Bi(EPh)2 (E = S (9), Se (10), Te (11)). It turned out that this is the result of instability of 9-11 in solution, and their decomposition provided compounds 6-8. The bismuth compounds containing the pincer-type ligand L2 (L 2 = [o,o-C6H3(CH2NMe 2)2]) containing an extra donor pendant arm were studied with the aim to support their stability by an additional N→Bi interaction. Thus, in situ preparation of the organobismuth(I) compound from L 2BiCl2 (12) and two equivalents of K[B(s-Bu)3H] followed by the addition of PhEEPh gave compounds L2Bi(EPh) 2 (E = S (13), Se (14), Te (15)). Compounds 13-15 showed no tendency for redistribution reaction, contrary to 9-11, due to the rigid coordination of both nitrogen donor atoms of the ligand L2 to the bismuth atom. All studied compounds were characterized by the help of 1H and 13C NMR spectroscopy, by elemental analysis, and except compounds 4, 14, and 15 by single-crystal X-ray diffraction analyses.
- Simon, Petr,Jambor, Roman,Ruiszicka, Ales,Dostal, Libor
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- The oxidation of diphenyl ditelluride by substituted orthobenzoquinones, and the molecular structure of 2O
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The reaction between tetrahalogeno-ortho-benzoquinones (X4C6O2-o; X=Cl, Br) and diphenyl ditelluride gives the unusual tellurium(IV) derivatives 2O.Crystallographic studies show that tellurium is coordinated by a substituted catecholate, a phenyl group, and a bridging oxygen.The mechanism of the reaction probably involves initial formation of a semiquinone-tellurium-phenyl species, since ESR spectroscopy identifies the presence of o-semiquinone radicals.A similar reaction was observed with (C6H5)2Te2 and 3,5-di-tert-butyl-ortho-benzoquinone.
- Tian, Zhigang,Tuck, Dennis G.
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- Metal-free chalcogenation of cycloketone oxime esters with dichalcogenides
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We report the metal-free chalcogenation of cycloketone oxime esters with dichalcogenides via a radical process. Because of the metal-free condition and use of readily accessible dichalcogenides, this method is an effective and green strategy for the synthesis of chalcogen-substituted butyronitrile.
- Ji, Liangshuo,Qiao, Jiamin,Liu, Junjie,Tian, Miaomiao,Lu, Kui,Zhao, Xia
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supporting information
(2021/06/15)
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- Synthesis, Mechanism Elucidation and Biological Insights of Tellurium(IV)-Containing Heterocycles
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Inspired by the synthetic and biological potential of organotellurium substances, a series of five- and six-membered ring organotelluranes containing a Te?O bond were synthesized and characterized. Theoretical calculations elucidated the mechanism for the oxidation-cyclization processes involved in the formation of the heterocycles, consistent with chlorine transfer to hydroxy telluride, followed by a cyclization step with simultaneous formation of the new Te?O bond and deprotonation of the OH group. Moreover, theoretical calculations also indicated anti-diastereoisomers to be major products for two chirality center–containing compounds. Antileishmanial assays against Leishmania amazonensis promastigotes disclosed 1,2λ4-oxatellurane LQ50 (IC50=4.1±1.0; SI=12), 1,2λ4-oxatellurolane LQ04 (IC50=7.0±1.3; SI=7) and 1,2λ4-benzoxatellurole LQ56 (IC50=5.7±0.3; SI=6) as more powerful and more selective compounds than the reference, being up to four times more active. A stability study supported by 125Te NMR analyses showed that these heterocycles do not suffer structural modifications in aqueous-organic media or at temperatures up to 65 °C.
- Souza, Jo?o Pedro A.,Menezes, Leociley R. A.,Garcia, Francielle P.,Scariot, Débora B.,Bandeira, Pamela T.,Bespalhok, Mateus B.,Giese, Siddhartha O. K.,Hughes, David L.,Nakamura, Celso V.,Barison, Andersson,Oliveira, Alfredo R. M.,Campos, Renan B.,Piovan, Leandro
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supporting information
p. 14427 - 14437
(2021/09/25)
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- A greener protocol for the synthesis of phosphorochalcogenoates: Antioxidant and free radical scavenging activities
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In this contribution, a metal- and base-free protocol has been developed for the synthesis of phosphorochalcogenoates (Se and Te) by using DMSO as solvent at 50 °C. A variety of phosphorochalcogenoates were prepared from diorganyl dichalcogenides and H-phosphonates, leading to the formation of a Chal-P(O) bond, in a rapid procedure with good to excellent yields. A full structural elucidation of products was accessed by 1D and 2D NMR, IR, CGMS, and HRMS analyses, and a stability evaluation of the phosphorochalcogenoates was performed for an effective operational description of this simple and feasible method. Typical 77Se{1H} (δSe = 866.0 ppm), 125Te{1H} (δTe = 422.0 ppm) and 31P{1H} (δP = ?1.0, ?13.0 and ?15.0 ppm) NMR chemical shifts were imperative to confirm the byproducts, in which this stability study was also important to select some products for pharmacological screening. The phosphorochalcogenoates were screened in vitro and ex vivo tests for the antioxidant potential and free radical scavenging activity, as well as to investigation toxicity in mice through of the plasma levels of markers of renal and hepatic damage. The pharmacological screening of phosphorochalcogenoates indicated that compounds have antioxidant propriety in different assays and not changes plasma levels of markers of renal and hepatic damage, with excision of 3g compound that increased plasma creatinine levels and decreased plasma urea levels when compared to control group in the blood mice. Thus, these compounds can be promising synthetic antioxidants that provide protection against oxidative diseases.
- Mailahn, Daniela H.,Iarocz, Lucas E.B.,Nobre, Patrick C.,Perin, Gelson,Sinott, Airton,Pesarico, Ana Paula,Birmann, Paloma T.,Savegnago, Lucielli,Silva, Márcio S.
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- Synthetic method of diaryl ditellurium ether compound
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The invention relates to a synthetic method of a diaryl ditellurium ether compound. The method comprises the following steps: putting phenylboronic acid or derivatives thereof, elemental tellurium, trimethylcyano silane and an organic solvent into a reaction container to obtain a mixed solution, heating the mixed solution to 110-140 DEG C, performing stirring to react for 18-30 hours at the temperature to obtain a reaction solution, and carrying out aftertreatment to obtain the diaryl ditellurium ether compound, the ratio of the phenylboronic acid or the derivative thereof to the elemental tellurium to the trimethylnitrile silane is (7-9): (8-10): 1. The synthetic method of the diaryl ditellurium ether compound has the following beneficial effects: 1, the reaction can be performed withoutmetal participation, so that the synthetic method is more environment-friendly and lower in cost; 2, the compatibility of a substrate is good; and 3, the preparation process is simple and easy to operate.
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Paragraph 0027-0041
(2021/03/31)
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- Metal-Free Synthesis of Unsymmetrical Aryl Selenides and Tellurides via Visible Light-Driven Activation of Arylazo Sulfones
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A protocol for the visible light driven preparation of unsymmetrical (hetero)aryl selenides and tellurides is described herein. The method exploits the peculiar photoreactivity of arylazo sulfones that act as thermally stable, precursors of aryl radicals under both photocatalyst- and additive-free conditions. The method developed shows an impressive versatility (more than fifty compounds isolated).
- Fagnoni, Maurizio,Li, Ankun,Li, Yuxuan,Liu, Junjie,Lu, Kui,Protti, Stefano,Shan, Xiwen,Tian, Miaomiao,Zhao, Xia
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p. 7358 - 7367
(2020/12/01)
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- Tellurides Bearing Sulfonamides as Novel Inhibitors of Leishmanial Carbonic Anhydrase with Potent Antileishmanial Activity
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We report for the first time a novel series of tellurides bearing sulfonamide as selective and potent inhibitors of the β-class carbonic anhydrase (CA; EC 4.2.1.1) enzyme expressed in Leishmania donovani protozoa. Such derivatives showed high activity against axenic amastigotes, and among them, compound 5g (4-(((3,4,5-trimethoxyphenyl)tellanyl)methyl)benzenesulfonamide) showed an IC50 of 0.02 μM being highly selective for the parasites over THP-1 cells with a selectivity index of 300. The in vitro and in vivo toxicity experiments showed compound 5g to possess a safe profile and thus paving the way for tellurium-containing compounds as novel drug entities.
- Angeli, Andrea,Etxebeste-Mitxeltorena, Mikel,Sanmartín, Carmen,Espuelas, Socorro,Moreno, Esther,Azqueta, Amaya,Parkkila, Seppo,Carta, Fabrizio,Supuran, Claudiu T.
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p. 4306 - 4314
(2020/05/25)
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- Diacetal Ditellurides as Highly Active and Selective Antiparasitic Agents toward Leishmania amazonensis
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Leishmaniasis is a neglected tropical disease and a public health concern in at least 98 countries, affecting mainly the poorest populations. Pharmaceuticals and chemotherapies available for leishmaniasis treatment have several limitations, which clearly justify the efforts to find new potential antileishmanial drugs. In this context, antiprotozoal activities toward different Leishmania species have been reported for hypervalent tellurium compounds, which motivated us to investigate, for the first time, the leishmanicidal properties of some nonhypervalent diaryl ditellurides. Thus, this work describes in vitro activity against Leishmania amazonensis and the cytotoxicities of diaryl ditellurides. Ditelluride LQ7 revealed a strong leishmanicidal activity on promastigotes and amastigotes at submicromolar levels (IC50 = 0.9 ± 0.1 and 0.5 ± 0.1 μmol L-1, respectively) and presented selectivity indexes greater than those of reference drug miltefosine. This preliminary study suggests that diaryl ditellurides may be promising scaffolds for the development of new agents for leishmaniasis treatment.
- Bandeira, Pamela T.,Souza, Jo?o Pedro A.,Scariot, Débora B.,Garcia, Francielle P.,Nakamura, Celso V.,De Oliveira, Alfredo R. M.,Piovan, Leandro
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supporting information
p. 806 - 810
(2019/05/06)
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- Synthesis of 2,3-bis-organochalcogenyl-benzo[b]chalcogenophenes promoted by Oxone
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We report here an alternative and tunable metal-free synthesis of benzo[b]chalcogenophenes via the electrophilic cyclization of 2-functionalized chalcogenoalkynes promoted by Oxone. The use of mild reaction conditions, efficiency and generality are characteristics of this new approach, which was suitable to convert different diselenides and 2-functionalized chalcogenoalkynes into a total of twenty-two 2,3-bis-organochalcogenyl-benzo[b]chalcogenophenes, eighteen of which were synthesized for the first time. The new compound 2-(butylselanyl)-3-(phenylselanyl)benzofuran was used as a substrate in the Pd-catalyzed reaction with phenylacetylene to access the Sonogashira's coupling derivative in good yield.
- Perin, Gelson,Soares, Liane K.,Hellwig, Paola S.,Silva, Marcio S.,Neto, José S. S.,Roehrs, Juliano A.,Barcellos, Thiago,Lenard?o, Eder J.
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supporting information
p. 6323 - 6331
(2019/04/25)
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- Reactivity of Selenocystine and Tellurocystine: Structure and Antioxidant Activity of the Derivatives
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l-Selenocystine (5) and l-tellurocystine (6) have been prepared and the reactivity of these amino acids, i.e., oxidation of 5 and 6, has been performed at various pH values. Hydrogen peroxide was used as an oxidant and it was treated with 5 and 6 in excess in acidic and basic media. Compound 5, upon oxidation, afforded SeIV and SeVI products. Selenocysteic acid [HO3SeCH2CH(NH2)COOH] 9, a novel SeVI compound, was isolated and characterised by single-crystal X-ray diffraction studies. In contrast, l-tellurocystine, upon oxidation with H2O2, afforded TeII and TeIV products. Zwitterionic organotellurolate(IV), [TeCl3CH2CH(NH3)COOH] 13, was isolated and characterised by NMR and IR spectroscopy, mass spectrometry and elemental analysis. Compound 13 crystallizes in an orthorhombic space group. l-Tellurocystine, when reduced with NaBH4, produced the desired tellurolate intermediate, which was trapped with bromoacetic acid. Furthermore, l- and d-tellurocysteine derivatives, [(RTeCH2CH(NH2)COOH) R=phenyl, substituted phenyl and naphthyl (24–39)] were synthesised and evaluated for their glutathione peroxidase (GPx)-like activities. The results show that l-tellurocysteine derivatives have higher activity than their D-tellurocysteine analogues. DFT calculations for l-tellurocysteine derivatives provided information about the bond lengths and bond angles. This study reveals that the introduction of naphthyl substituents (35–38) leads to twisted conformation of the amino acid derivatives.
- Satheeshkumar, Kandhan,Raju, Saravanan,Singh, Harkesh B.,Butcher, Ray J.
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supporting information
p. 17513 - 17522
(2018/11/23)
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- Syntheses and Structures of Zinc(tmeda)bis(aryltellurolato) and its Facile Chalcogenospecific Ligand Exchange Reactivity
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Anaerobic treatment of Zn(tmeda)Br2, where tmeda denotes N,N,N′,N′-tetramethylethylenediamine, with a solution of Na(TeAr), sodium aryltellurolate, in ethanol in a 1:2 stoichiometry led to the formation of highly air sensitive Zn(tmeda)(TeAr)2 (1–3), while a 1:1 stoichiometry afforded Zn(tmeda)Br(TeAr) (4). Crystallography revealed all complexes to be monomeric with four coordinate central zinc atoms bound to tmeda and two TeAr, or a TeAr and a Br ligand. Upon mixing two symmetrically substituted Zn(tmeda)(TeAr)2 complexes in solution, 125Te NMR revealed a facile ligand exchange providing Zn(tmeda)(TeAr)(TeAr′). In addition, Zn(tmeda)(TeAr)(TeAr′) complexes form on mixing symmetric Zn(tmeda)(TeAr)2 complexes and (TeAr′)2. The lability of the zinc complexes was put to advantage in ligand-substitution reactions wherein treatment of SnCl4 with Zn(tmeda)(TeAr)2 affords Sn(TeAr)4 in excellent yields without the concurrent formation of the redox product (TeAr)2. The apparent lability of the Zn–Te bond prevented the volatilization of 1–3 for their use as chemical vapor deposition precursors for the fabrication of ZnTe thin films. On heating, to volatize the complexes, the complexes decompose to cubic ZnTe and TeAr2 sublimes from the samples. Thermal gravimetric analysis indicates the loss of tmeda followed by the loss of TeAr2.
- Behr, Sandra,Bestvater, Thorsten,Feldmann, Arnold,Kirschbaum, Kristin,Conrad, Olaf,Giolando, Dean M.
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p. 1431 - 1438
(2018/09/25)
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- Synthesis of Terminal Ethynyl Aryl Selenides and Sulfides Based on the Retro-Favorskii Reaction of Hydroxypropargyl Precursors
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The retro-Favorskii reaction is an excellent way to achieve terminal alkynes. Methodologies that connect the synthesis of terminal alkynes and organochalcogen motifs are important for the construction of novel compounds. Fourteen new terminal alkynes containing either Csp?S or Csp?Se bonds were selectively prepared through the retro-Favorskii reaction from the respective carbinol precursors. It was discovered that terminal chalcogen alkynes were stable for weeks if stored as a solution in hexanes.
- Lopes, Eric F.,Dalberto, Bianca T.,Perin, Gelson,Alves, Diego,Barcellos, Thiago,Lenard?o, Eder J.
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p. 13760 - 13765
(2017/09/08)
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- An alternative approach to differentially substituted 2-oxazoline chalcogen derivatives
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In this study we present an alternative method to obtain several substituted mono or bis-2-oxazolines containing a chalcogen atom as a tether element. Alkylation of 2-tosyloximethylene-2-oxazoline with an appropriate sodium, lithium or potassium alkoxide yielded the corresponding ether. Introduction of sulfur or selenium was easily accomplished using the corresponding sodium salts. The 77Se NMR for alkyl or aryl 2-methylene-2-oxazoline selenides shows good correlation with the electronegativity pattern of substituents. Most products containing oxazolinyl-chalcogen were stable under the usual experimental conditions. However, the tellurium derivatives showed unusual sensitivity to light and oxygen, decomposing through a very complex mechanistic pathway. As a result of this oxidative process, 4,4-dimethyl-2-oxazoline-2-carbaldehyde could be isolated and fully characterized for the first time, in 17% yield.
- De Mello, Murilo B.M.,Clososki, Giuliano C.,Piovan, Leandro,De Oliveira, Alfredo R.M.
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- Platinum-Mediated Activation of Coordinated Organonitriles by Telluroethers in Tetrahydrofuran: Isolation, Structural Characterization, and Density Functional Theory Analysis of Intermediate Complexes
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The reactions of [PtCl2(NCR)2] with telluroethers (ArAr′Te) in organic solvents have been investigated. The reactions in dichloromethane yield [PtCl2(TeArAr′)2], while those in tetrahydrofuran (THF) give different products depending on the steric demands of the aryl groups on tellurium, the molarity of the reactants, and the reaction conditions. The reactions between [PtCl2(PhCN)2] and TeArAr′ in 1:1 molar ratio at room temperature in THF yield several products, like [PtCl2(TeArAr′)2] (Ar/Ar′ = Ph/Ph, o-tol/Mes, Mes/Mes), [PtCl2(PhCN){NC(O)Ph[TeMes(o-tol)]}], and [PtCl2{NC(O)Ph(TeMes2)}2]. The reaction with TeMes2 in refluxing THF gave [PtCl2{NC(Ph)C4H7O}{NC(O)Ph(TeMes2)}] and [PtCl(TeMes2){Te(Mes)CH2C6H2Me2}], depending on the duration of heating. Reaction of [PtCl2(PhCN)2] with TeArMes afforded [PtCl2(TeArMes)2] (Ar = Ph, o-tol, and Mes), the formation of which decreased with increasing steric demand of the Ar group, together with [PtCl2{NC(O)Ph(TeArMes)}2]. The telluroether in the latter binds to nitrogen, and tellurium exists in the formal oxidation state of +4 (from XPS). The tellurium in these complexes exhibits secondary interactions with platinum (J(195Pt-125Te) = 309-347 Hz) and with the carbonyl oxygen. These complexes slowly dissociate in solution to give [PtCl2(TeMesAr){NC(O)Ph(TeMesAr)}], finally leading to the formation of [PtCl2(TeMesAr)2]. Molecular structures of trans-[PtCl2(PhCN){NC(O)Ph[TeMes(o-tol)]}], trans-[PtCl2{NC(O)Ph(TeMes2)}2], trans-[PtCl2{NC(Ph)C4H7O}{NC(O)Ph(TeMes2)}], trans-[PtCl2{NC(O)Ph[TeMes(o-tol)]}2], trans-[PtCl2(TeMes2){NC(O)Ph(TeMes2)}], trans-[PtCl2{NC(O)Me(TeMes2)}2], and [PtCl(Te-o-tol){NC(O)Ph}2] have been unambiguously established by single-crystal X-ray diffraction analyses. Density functional theory calculations for some of the complexes were performed, and geometrical parameters are in good agreement with the values obtained from X-ray analyses.
- Kolay, Siddhartha,Wadawale, Amey,Nigam, Sandeep,Kumar, Mukesh,Majumder, Chiranjib,Das, Dasarathi,Jain, Vimal K.
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supporting information
p. 11741 - 11750
(2015/12/31)
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- Cyclopalladation of telluro ether ligands: Synthesis, reactivity and structural characterization
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Treatment of [PdCl2(PhCN)2] with diaryl telluride in 1:2 molar ratio gave mononuclear palladium complexes, trans-[PdCl2(TeR2)2] (1) (R = Mes (1a) (Mes = 2,4,6-trimethylphenyl), Ph (1b), o-tol (1c) (o-tol = ortho-tolyl)). Reaction of [PdCl2(TeMes2)2] with one equivalent of [PdCl2(PhCN)2] or Na2PdCl4 with TeRR′ afforded chloro-bridged binuclear complexes, [Pd2(μ-Cl)2Cl2(TeRR′)2] (2) (R/R′ = Mes/Mes (2a); Mes/Ph (2b); Ph/Ph (2c)). A toluene-methanol solution of trans-[PdCl2(TeMes2)2] on refluxing for 30 minutes yielded a binuclear cyclopalladated complex, [Pd2(μ-Cl)2{CH2C6H2(4,6-Me2)TeMes)}2] (3). When the refluxing was prolonged, a mononuclear complex cis-[PdCl2{MesTeCH2C6H2(4,6-Me2)TeMes}] (4) was isolated. Treatment of palladium acetate with TeMes2 afforded an acetato-bridged analogue of 3, [Pd2(μ-OAc)2{CH2C6H2(4,6-Me2)TeMes}2] (5a) together with a very minor component, a tetranuclear complex, [Pd(μ-OAc)(μ-TeMes)]4 (6). This reaction with unsymmetrical tellurides, MesTeR, also gave cyclopalladated complexes [Pd2(μ-OAc)2{CH2C6H2(4,6-Me2)TeR}2] (R = o-tol (5b) and Ph (5c)) in which 2-methyl of the mesityl group of the telluride was exclusively metallated. The complex trans-[PdCl2(TeMes2)2] on refluxing in xylene gave palladium telluride, Pd7Te3. These complexes were characterized by elemental analyses, IR and NMR (1H, 13C and 125Te) spectroscopy. The molecular structures of trans-[PdCl2(TeMes2)2] (1a), [Pd2(μ-Cl)2Cl2(TeMes2)2]·2acetone (2a·2acetone), cis-[PdCl2{MesTeCH2C6H2(4,6-Me2)TeMes}] (4), [Pd2(μ-OAc)2{CH2C6H2(4,6-Me2)TeMes)}2]·toluene (5a·toluene), [Pd2(μ-OAc)2{CH2C6H2(4,6-Me2)Tetol-o}2] (5b) and [Pd(μ-OAc)(μ-TeMes)]4 (6) were established by single crystal X-ray diffraction analyses. The mononuclear complex 1a was isolated in two polymorphic forms each with the trans configuration. This journal is
- Kolay, Siddhartha,Kumar, Mukesh,Wadawale, Amey,Das, Dasarathi,Jain, Vimal K.
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supporting information
p. 16056 - 16065
(2015/01/09)
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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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- Reversible near-infrared fluorescent probe introducing tellurium to mimetic glutathione peroxidase for monitoring the redox cycles between peroxynitrite and glutathione in vivo
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The redox homeostasis between peroxynitrite and glutathione is closely associated with the physiological and pathological processes, e.g. vascular tissue prolonged relaxation and smooth muscle preparations, attenuation hepatic necrosis, and activation matrix metalloproteinase-2. We report a near-infrared fluorescent probe based on heptamethine cyanine, which integrates with telluroenzyme mimics for monitoring the changes of ONOO-/GSH levels in cells and in vivo. The probe can reversibly respond to ONOO- and GSH and exhibits high selectivity, sensitivity, and mitochondrial target. It is successfully applied to visualize the changes of redox cycles during the outbreak of ONOO- and the antioxidant GSH repair in cells and animal. The probe would provide a significant advance on the redox events involved in the cellular redox regulation.
- Yu, Fabiao,Li, Peng,Wang, Bingshuai,Han, Keli
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p. 7674 - 7680
(2013/07/05)
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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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- 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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- Ultrasound-assisted synthesis of symmetrical biaryls by palladium-catalyzed detelluration of 1,2-diarylditellanes
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An ultrasound-assisted synthesis of functionalized symmetrical biaryls with electron-withdrawing or electron-donating substituents is described and illustrated by the palladium-catalyzed detelluration of 1,2-diarylditellanes. This procedure offers easy access to symmetrical biaryls in short reaction time and the products are achieved in good to excellent yields.
- Singh, Fateh V.,Stefani, Hélio A.
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experimental part
p. 863 - 867
(2010/03/24)
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- Aerobic photooxidation of phosphite esters using diorganotelluride catalysts
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Diorganotellurides containing bulky aromatic substituents are found to catalyze the photooxidation of phosphite esters using aerobic oxygen as a terminal oxidant. A Hammett plot with substituted triaryl phosphites yielding p = 2.88 agrees with a nucleophilic oxygen transfer from telluroxide to phosphite.2009 American Chemical Society.
- Oba, Makoto,Okada, Yasunori,Nishiyama, Kozaburo,Ando, Wataru
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supporting information; experimental part
p. 1879 - 1881
(2009/10/10)
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- The soft nucleophilicity of organotellurolates driving the S N2-type lactone ring-opening reaction
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Lithium and magnesium organotellurolates were reacted with lactones producing the corresponding tell-urocarboxylic acids. Treatment of the reaction mixture with lithium aluminum hydride allowed the isolation of the corresponding hydroxytellurides in a one-pot operation.
- Silva, Márcio S.,Dos Santos, Alcindo A.,Comasseto, Jo?o V.
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experimental part
p. 6498 - 6501
(2011/02/23)
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- Synthesis and properties of calix[4]arene telluropodant ethers as Ag + selective sensors and Ag+, Hg2+ extractants
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Three novel phenyltelluroalkoxyl functionalized tweezer-like calix[4]arenes 6-8 and two monophenyltelluropropoxyl functionalized calix[4]arenes 10 (cone conformer) and 12 (partial cone conformer) were synthesized and characterized. They are good Ag+
- Lu, Yan,Lu, Yang,Li, Yuanyuan,He, Song,Zeng, Xianshun,Liu, Changying,Chen, Langxing
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experimental part
(2010/04/22)
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- Reaction of β-ethoxyvinyl lithiums generated from phenyltellanyl- and ethyltellanylacetaldehyde diethyl acetals with aldehydes and ketones and successive hydrations
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Reactions of α-tellanyl-β-ethoxyvinyl lithiums of aldehydes and ketones proceeded in good to high yields and the successive treatment with acids gave the α-tellanyl α,β-unsaturated aldehydes. α-Tellanyl α,β-unsaturated aldehydes easily transformed to more useful compounds.
- Yoshimatsu, Mitsuhiro,Hatanaka, Fumihiro
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p. 248 - 253
(2007/10/03)
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- Facile access to aryltellurium compounds from arylboronic acids
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Arylboronic acids were treated with tellurium tetrachloride to generate substituted aryltellurium trichlorides, which were reduced to the corresponding diaryl ditellurides in good to excellent overall yields. Representative products include diphenyl ditel
- Clark, Aaron R.,Nair, Rashmi,Fronczek, Frank R.,Junk, Thomas
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p. 1387 - 1389
(2007/10/03)
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- Photoactive indicator compounds
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Photoactive indicator compounds of the formula STR1
- -
-
-
- A New Approach to the Synthesis of Symmetrical Bis(organylchalcogeno)acetylenes: Scope and Limitations
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A new general method to prepare bis(organylchalcogeno)acetylenes R-Y-CC-Y-R (Y = S, Se, Te) by dehydrochlorination of the corresponding 1,2-bis(organylchalcogeno)chloroethylenes R-Y-CH=CCl-Y-R with tert-BuOK/tert-BuOH and/or KOH/DMSO is developed.Dechlorination of 1,2-bis(organylchalcogeno)-1,2-dichloroethylenes R-Y-CCl=CCl-Y-R (Y = S, Se, Te) with BuLi in ether or THF is effective only for sulfur derivatives.With Y = Se and alkyl substituents, substitution of the chlorine atom by a butyl group takes place giving rise to 5,6-bis(alkylseleno)dec-5-ene .With aryl substituents, an attack of the ArSe-group by the Bu-radical is observed leading to an aryl butyl selenide.In the case of the tellurium compound Ph-Te-CCl=CCl-Te-Ph, there is a competition between dechlorination to give Ph-Te-CC-Te-Ph, and substitution to produce the phenyl butyl telluride. - Keywords: bis(organylchalcogeno)acetylene; 1,2-bis(organylchalcogeno)chloroethylene; 1,2-bis(organochalcogeno)-1,2-dichloroethylene.
- Martynov, Alexander V.,Guillanton, Georges Le
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p. 823 - 831
(2007/10/03)
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- Fluoroselenylation of acetylenes with xenon difluoride-diorganyl diselenides and xenon difluoride-phenylseleno(trialkyl)silanes
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A new, efficient method of fluoroselenenylation of terminal, and open-chain symmetric and unsymmetric disubstituted acetylenes and cycloalkynes, gives vicinal (E)-fluoroalkenyl selenides in moderate to high yields by addition of selenenyl fluoride equivalents. These are formed in situ from xenon difluoride and diaryl, dibenzyl or primary and secondary dialkyl diselenides. Alternatively, the benzeneselenenyl fluoride equivalent is formed by treatment of more reactive phenylselenotrialkylsilanes with xenon difluoride. The regiochemistry of the addition is strongly dependent on the steric effects of substituents bonded to the acetylene.
- Poleschner,Heydenreich,Spindler,Haufe
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p. 1043 - 1049
(2007/10/02)
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- Highly Regio- and Stereoselective Alkylation of vic-Bis(phenyltelluro)alkenes with Organocuprates
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Alkylation of vic-bis(phenyltelluro)alkenes 1 with lithium dialkylcuprates takes place regioselectively at the terminal carbon of 1 to provide the corresponding 1-alkyl-2-phenyltelluroalkenes (2) stereoselectively in good yields.
- Ogawa, Akiya,Tsuboi, Yasunori,Obayashi, Ryoichi,Yokoyama, Kazuyuki,Ryu, Ilhyong,Sonoda, Noboru
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p. 1600 - 1601
(2007/10/02)
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- Photo-induced ditelluration of acetylenes with diphenyl ditelluride
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Diphenyl ditelluride (PhTeTePh) adds to a variety of acetylenes upon irradiation with visible light in the absence of solvent to provide vic-bis(phenyltelluro)alkenes in good yields. The reaction may proceed by a radical-chain mechanism that includes the addition to acetylenes of phenyltelluro radical (phTe·) generated in situ by photolysis of diphenyl ditelluride, followed by the S(H)2 reaction between thus formed β-(phenyltelluro)alkenyl radicals and diphenyl ditelluride. In the cases of unactivated acetylenes such as 1-octyne, the addition proceeds stereoselectively to provide only (E)-vic-bis(phenyltelluro)alkenes. Contrary to this, activated acetylenes like phenylacetylene give rise to a mixture of E- and Z-isomers of vic-bis(phenyltelluro)alkenes. Since the obtained vic-bis(phenyltelluro)alkenes indicate absorption in the near-UV, irradiation with near-UV light in solvent causes a novel reverse reaction of the adducts to the starting acetylenes and diphenyl ditelluride. Accordingly, irradiation with visible light (> 400 nm) under high concentrations of the substrates induces the addition of (PhTe)2 to acetylenes, whereas irradiation with near-ultraviolet (> 300 nm) under dilution condition causes the reverse reaction.
- Ogawa,Yokoyama,Obayashi,Han,Kambe,Sonoda
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p. 1177 - 1188
(2007/10/02)
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- Sodium telluride in N-methyl-2-pyrrolidone: An efficient telluration system for the synthesis of aromatic tellurides and ditellurides
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Sodium telluride prepared in situ from tellurium and sodium hydride in N-methyl-2-pyrrolidone was found to act as an efficient tellurating agent for nonactivated aromatic iodides, providing a simple route to a variety of diaryl tellurides, alkyl aryl tellurides and diaryl ditellurides.
- Suzuki,Nakamura
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p. 549 - 551
(2007/10/02)
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- TELLURIUM AMIDES AS A NEW TELLURATING AGENT
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Two types of tellurium amides have been prepared by the treatment ot ArTeI or TeCl4 with LiNR2 in THF, and their reaction with acetylenes gave vinyl tellurides and dialkynyl tellurides
- Murai, Toshiaki,Imaeda, Kaori,Kajita, Satoshi,Kimura, Koji,Ishihara, Hideharu,Kato, Shinzi
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p. 239 - 242
(2007/10/02)
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- Direct Synthesis of Some Diaryl Ditellurides from Aryl Halides
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The reaction of aryl halides with sodium hydrogen telluride in dimethylformamide is studied.Some diaryl ditellurides are synthesized under mild conditions by the reaction.
- Liu, Jianfei,Qiu, Mei,Zhou, Xunjun
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p. 2759 - 2767
(2007/10/02)
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- Improved preparation of diaryl ditellurides
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Diaryl ditellurides have been synthesized from aryl bromides via lithiation, tellurium insertion, and ferricyanide oxidation of the resulting lithium arenetellurolates.
- Engman, Lars,Persson, Joachim
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- LITHIUM ORGANYL-POLYCHALCOGENOLATES
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Lithium organyl-selenolates, RSeLi or tellurolates, RTeLi insert further equivalents of chalcogens with formation of selenyl-selenolates, RSeSeLi or tellurenyl-tellurolates, RTeTeLi (R=Me, n-Bu, s-Bu, t-Bu, Ph).Mixed anions are only formed if the chalcogen insertion order corresponds with an increase of electronegativity, i.e.: RTeSeLi, RTeSLi, RSeSLi and n-BuTeSeSLi.All species have been characterized by 77-Se and 125-Te NMR-spectroscopy.Tellurenyl-tellurolates and tellurenyl-selenolates are stable at room temperature, selenyl-selenolates and chalcogenyl-thiolatesdisproportionate.The chemical integrity of the chalcogenyl-chalcogenolates was checked by methylation with methyl triflate.The formed organyl-methyl-dichalcogenides exhibit symmetrization equilibria that are also obtained by mixing the symmetric conpounds.Oxidation of tellurenyl-selenolates affords di(organyl-tellurenyl) selenides, (RTe)2Se (R=Me, n-Bu, t-Bu, Ph, p-MeC6H4, 2-thienyl) and (RTe)2Se2 for R=(Me3Si)3C.In solution (RTe)2Se are in equilibrium with R2Te2 and (RTe)2Se2.
- Koellemann, Christoph,Obendorf, Dagmar,Sladky, Fritz
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- REACTIONS OF ACETYLACETONE WITH ORGANOTELLURIUM (IV) CHLORIDES-C1 BONDED ACETYLACETONATES OF TELLURIUM(IV)
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The reactions of acetylacetone (AcAc) with ArTeCl3 (I), Ar2TeCl2 (II) and Ar3TeCl (III) (where Ar = phenyl, 4-hydroxyphenyl, 4-methoxyphenyl, 4-ethoxyphenyl, 3-methyl-4-hydroxyphenyl and 3,4-dihydroxyphenyl) have been investigated.The I gives ArTe(C5H7O2)Cl2 (IV) type derivatives but II and III do not react even on prolonged refluxing in the presence of anhydrous AlCl3.The structural features of the new acetonylacetone derivatives (IV) have been explored by IR, PMR, and CMR spectroscopy.The effect of phenyl ring substituents on the keto-enol tautomerism of IVhas been found to be minor.The bond formation between Te and C1 of AcAc and intramolecular secondary interaction between the oxygen of AcAc and Te have been inferred from spectral data.
- Khandelwal, Bishan L.,Singh, Ajai K.,Bhandari, Narendra S.
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p. 157 - 166
(2007/10/02)
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- Application of phosphine tellurides to the preparation of group II-VI (2-16) semiconductor materials
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In order to find low-temperature routes to metal tellurides, we have investigated some of the reactions of phosphine tellurides. Via the phosphine telluride, tellurium is chemically transported by PMe3 under very mild conditions (T ≈ 150°C). Triethylphosphine telluride reacts with Hg at room temperature and with HgR2 (R = Et, Ph) at 115°C, in each case giving HgTe as the sole solid-state product. We studied the reaction with HgPh2 in greater detail, showing that Ph2Te and Ph2Te2 are the major organic products.
- Steigerwald,Sprinkle
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p. 245 - 246
(2008/10/08)
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- Oxidation of Olefins with Benzenetelluric Anhydride
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Olefins were found to be oxidized by use of benzenetellurinic anhydride in acetic acid leading to vic-diacetates.Benzenetellurenic acid derivatives formed in situ are suggested as the active species.This diacetoxylation proceeds in net syn fashion probably via anti acetoxytellurenylation of the olefin followed by displacement of the phenyltelluro group by an acetoxy group with inversion.
- Kambe, Nobuaki,Tsukamoto, Takashi,Miyoshi, Noritaka,Murai, Shinji,Sonoda, Noboru
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p. 269 - 272
(2007/10/02)
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- Synthesis of chelating ditelluroether ligands, RTeCH2CH2CH2TeR (R = Me, Ph)
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RTeLi (R = Me, Ph), prepared in situ in tetrahydrofuran from RLi and Te, react at low temperatures with 1,3-dihalopropanes, X(CH2)3X (X = Cl, Br), to give high yields of RTe(CH2)3TeR. At ambient or higher temperatures these reactions yield mainly R2Te2. The RTeCH2TeR are made analogously, but 1,2-dichloroethane gave only R2Te2.
- Hope, Eric G.,Kemmitt, Tim,Levason, William
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p. 206 - 207
(2008/10/08)
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- REACTIONS OF SULFOHYDRAZIDES WITH BENZENESELENIC ACID, SELENIUM HALIDES, AND SULFUR HALIDES. A CONVENIENT PREPARATION OF SELENOSULFONATES AND THIOSULFONATES
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The oxidation of sulfohydrazides with benzeneselenic acid provides an efficient and convenient preparation of selenosulfonates.Se-Phenyl p-tolueneselenosulfonates was also produced in good to excellent yield from the reaction of p-toluenesulfohydrazide with PhSeCl, PhSeBr, or PhSeCl3.Sulfohydrazide react with sulfenyl halides or with PhSBr3 to produce thiosulfonates generally high yield.The treatment of p-toluenesulfohydrazide with benzenetellurinic acid, PhTeCl3, or PhTeBr3, afforded only diphenyl ditelluride and not the corresponding tellerosulfonate.
- Back, Thomas G.,Collins, Scott,Krishna, M. Vijaya
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- Preparation and Some Reactions of Thioacyl Diphenylthiophosphinoyl and Thioacyl Diphenylphosphino Sulfides
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The reaction of sodium or caesium dithiocarboxylates with diphenylthiophosphinic and diphenylselenophosphinic chlorides gives purple thioacyl diphenylthiophosphinoyl 5 and dark green thioacyl diphenylselenophosphinoyl sulfides 6, which are useful thioacylating reagents under mild reaction conditions.Thioacyl diphenylphosphino sulfides 22, which can be obtained by the similar method using diphenylphosphinous chlorides, react with methanol to yield the corresponding methyl dithiocarboxylates 15, while the reactions of 22 with N-chlorosuccinimide lead to hitherto unknown N-(thioacetylthio)succinimides 28.
- Kato, Shinzi,Goto, Masahisa,Hattori, Rikizoh,Nishiwaki, Koh-ichi,Mizuta, Masateru,Ishida, Masaru
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p. 1668 - 1683
(2007/10/02)
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- REACTIONS OF TELLURIUM(IV) CHLORIDES WITH SOME ORGANOSILICON HYDRIDES
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The reactions of several organosilicon hydrides PhnSiH(4-n), n = 1, 2; R3SiH, R3 = Ph3, Ph2Me, PhMe2, (n-C6H13)3; (p-Me2HSi)2C6H4, with TeCl4 in benzene resulted in the formation of tellurium metal and chlorosilanes in 75-90percent yields.Similar reactions with aryltellurium trichlorides (RTeCl3, R = Ph, p-MeOC6H4, p-EtOC6H4) proceeded in two different ways.On stirring at room temperature for 6-8 h, diaryl ditellurides and chlorosilanes were obtained in 70-95percent yields whereas on refluxing for 6-10 h, tellurium powder and diaryltellurium dichlorides were obtained along withthe chlorosilanes in 80-95percent yields.Diaryltellurium dichlorides (R2TeCl2, R = Ph, p-MeOC6H4) did not react readily with PhSiH3 nor with Ph3SiH.
- Chadha, Raj K.,Drake, John E.,Neo, Mary K. H.
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- ALKALINE HYDROLYSIS OF DIARYL DITELLURIDES UNDER PHASE TRANSFER CONDITIONS; SYNTHESIS OF ALKYL ARYL TELLURIDES
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The disproportionation reaction of diaryl ditellurides with sodium hydroxide under phase transfer conditions at room temperature is described for the first time.The phase transfer catalyst used is 2HT-75, a trade name for a mixture of dialkyldimethylammonium chlorides.The intermediates aryl tellurolates react "in situ" with alkyl halides to give the corresponding alkyl aryl tellurides (ArTeR) in 52-72percent yield.The following compounds were prepared: Ar = C6H5, R = CH3(CH2)3CH2,(CH3)2CHCH2CH2, (CH3)2CHCH2, CH3CHBrCH2CH2, CH3(CH2)8CH2, C6H5CH2, ClCH2, C6H5CH2CH2, CH2=CHCH2, C6H5CH=CHCH2, C6H5SeCH2, ; Ar = p-CH3C6H4, R = CH3(CH2)2CH2; Ar = p-CH3OC6H4, R = CH3(CH2)2CH2; Ar = p-C2H5OC6H4, R = CH3(CH2)2CH2; Ar = 2-naphthyl, R = CH3(CH2)2CH2.
- Comasseto, J. V.,Ferreira, J. T. B.,Val, Fontanillas
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p. 261 - 266
(2007/10/02)
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- ORGANOTELLURIUM COMPOUNDS 8. ARYLTELLUROLS AS REDUCING AGENTS
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Phenyltellurol and 2-thienyltellurol, generated in situ, have been found to act as selective reductants towards a number of representative organic substrates.
- Akiba, Mitsuo,Cava, Michael P.
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p. 1119 - 1128
(2007/10/02)
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- New Aspects of the Telluroxide Elimination. A Facile Elimination of sec-Alkyl Phenyl Telluroxide Leading to Olefins, Allylic Alcohols, and Allylic Ethers
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The utility of the telluroxide for olefin synthesis, a reaction which previously appeared to be of little value, is described.Treatment of sec-alkylphenyltellurium dibromides, except for the cyclohexyl system, with aqueous NaOH at room temperature affords olefins, allylic alcohols, and/or allylic ethers in high yields presumably via the formation of sec-alkyl phenyl telluroxides and their facile telluroxide elimination.As to the formation of linear olefins, more preference for elimination toward the less substituted carbon was observed than the selenoxide and sulfoxide eliminations.In the cyclododecyl case only trans-cyclododecene was formed as an olefin component in a sharp contrast to the selenoxide elimination that affords a 1:1 mixture of cis and trans isomers.On the contrary, in the n-alkyl and cyclohexyl cases the corresponding telluroxides are stable compounds that afford similar elimination products including vinylic ethers only by neat pyrolysis at temperatures above 200 deg C.
- Uemura, Sakae,Fukuzawa, Shin-ichi
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p. 2748 - 2752
(2007/10/02)
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