- Photolysis of phenyltellurotrifluoroacetimidates; a new approach to generation of α-trifluoroacetimidoyl radicals leading to the synthesis of indole derivatives
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Photolysis of N-aryl phenyltellurotrifluoroacetimidates generates N-aryl trifluoroacetimidoyl radicals, which undergo an intramolecular exo-attack to carbon-carbon triple bond leading to indole derivatives.
- Ueda,Watanabe,Uemura,Uneyama
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- Direct assembly of multiply oxygenated carbon chains by decarbonylative radical-radical coupling reactions
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Pentoses and hexoses contain more than three oxygen-bearing stereocentres and are ideal starting materials for the synthesis of multiply oxygenated natural products such as sagittamide D, maitotoxin and hikizimycin. Here we demonstrate new radical-radical homocoupling reactions of sugar derivatives with minimal perturbation of their chiral centres. The radical exchange procedure using Et 3 B/O 2 converted sugar-derived α-alkoxyacyl tellurides into α-alkoxy radicals via decarbonylation and rapidly dimerized the monomeric radicals. The robustness of this process was demonstrated by a single-step preparation of 12 stereochemically diverse dimers with 6-10 secondary hydroxy groups, including the C5-C10 stereohexad of sagittamide D and the enantiomer of the C51-C60 stereodecad of maitotoxin. Furthermore, the optimally convergent radical-radical cross-coupling reaction achieved a one-step assembly of the protected C1-C11 oxygenated carbon chain of the anthelmintic hikizimycin. These exceptionally efficient homo- and heterocoupling methods together provide a powerful strategy for the expedited total synthesis of contiguously hydroxylated natural products.
- Masuda, Kengo,Nagatomo, Masanori,Inoue, Masayuki
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- N-[4-(phenyl telluro) butyl] phthalimide: Synthesis, spectral characterization, DFT studies and its complexes with mercury salts
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Reaction of N-[4?bromo butyl] phthalimide) with C6H5Te?Na+ (generated insitu) under N2 environment gives N-[4-(phenyl telluro)butyl] phthalimide (L) as a cream color solid. Interaction of the L with d
- Chopra, Ambika,Fatima, Aysha,Javed, Saleem,Siddiqui, Nazia,Srivastava, Sanjay Kumar
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- Molecular structure and real-space bonding descriptors (AIM, ELI-D) of Phenyl(triphenylstannyl)telluride
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The previously known phenyl(triphenylstannyl)telluride, PhTeSnPh 3, was prepared by the reaction of triphenyltin chloride, Ph 3SnCl, with sodium phenyltellurolate, Na(TePh), in liquid ammonia. The molecular structure established by X
- Beckmann, Jens,Heinrich, Darina,Mebs, Stefan
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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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- Discovery of new 2, 5-disubstituted 1,3-selenazoles as selective human carbonic anhydrase IX inhibitors with potent anti-tumor activity
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A series of disubstituted selenazole derivatives was synthetized and evaluated as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors against the human (h) isoforms hCA I, II, IV, VA, VB and IX, involved in a variety of diseases including glaucoma, retinitis pigmentosa, epilepsy, arthritis and tumors. The investigated compounds showed potent inhibition against the tumor-associated transmembrane hCA IX, with KIs in the subnanomolar – low nanomolar range, and were evaluated for their effects on cell viability against the human prostate (PC3) and breast (MDA-MB-231) cancer cell lines, showing effective anti-tumor activity. These selenazoles are interesting leads for the development of new, isoform-selective CA IX inhibitors.
- Angeli, Andrea,Trallori, Elena,Ferraroni, Marta,Di Cesare Mannelli, Lorenzo,Ghelardini, Carla,Supuran, Claudiu T.
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p. 1214 - 1222
(2018/09/12)
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- Structural variation in [PdX2{RE(CH2)nNMe2}] (E = Se, Te; X = Cl, OAc) complexes: Experimental results, computational analysis, and catalytic activity in Suzuki coupling reactions
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A series of chalcogenoether ligands RE(CH2)nNMe2 (1) [E = Se or Te; R = Ph, o-tol (o-tol = ortho-tolyl), Mes (Mes = 2,4,6-trimethylphenyl); n = 2 or 3] and their palladium complexes [PdX2{RE(CH2)
- Paluru, Dilip K.,Dey, Sandip,Wadawale, Amey,Maity, Dilip K.,Bhuvanesh, Nattamai,Jain, Vimal K.
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p. 397 - 407
(2015/01/30)
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- Synthesis of amphiphilic, chalcogen-based redox modulators with in vitro cytotoxic activity against cancer cells, macrophages and microbes
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Several amphiphilic, chalcogen-based redox modulators have been synthesized which exhibit a widespread, yet in some instances also selective, biological activity which is most likely based on their ability to modulate the intracellular redox balance and t
- Du, Peng,Viswanathan, Uma M.,Khairan, Khairan,Buric, Tomislav,Saidu, Nathaniel E. B.,Xu, Zhanjie,Hanf, Benjamin,Bazukyan, Inga,Trchounian, Armen,Hannemann, Frank,Bernhardt, Ingolf,Burkholz, Torsten,Diesel, Britta,Kiemer, Alexandra K.,Schaefer, Karl-Herbert,Montenarh, Mathias,Kirsch, Gilbert,Jacob, Claus
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supporting information
p. 25 - 31
(2014/01/06)
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- (Aryltelluro)formates as precursors of alkyl radicals: Thermolysis and photolysis of primary and secondary alkyl (aryltelluro)formates
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Alkyl (aryltelluro)formates are effective precursors of oxyacyl, methyl, and primary and secondary alkyl radicals. At room temperature, irradiation of a benzene solution of methyl (aryltelluro)-formates 10-12, 2-methylpropyl (aryltelluro)formates 14 and 15, octyl (phenyltelluro)formate (17), cyclohexyl (aryltelluro)formates 19 and 20, 3β-cholestanyl (aryltelluro)formates 22 and 23, cholesteryl (phenyltelluro)formate (24) and benzyl (phenyltelluro)formate (27) with a 250-W low-pressure mercury lamp leads to the formation of oxyacyl radicals (34), which can be trapped by diphenyl diselenide to give the corresponding alkyl (phenylseleno)formates 13, 16, 18, 21, 24, 26, and 28 with excellent overall conversions. Thermolysis of these telluroformates at 160 °C in the dark leads to the formation of methyl and primary and secondary alkyl aryl tellurides 36-43 in excellent yields. Presumably, these transformations involve oxyacyl radicals, which undergo subsequent decarboxylation at the elevated temperature to afford alkyl radicals, which become involved in further radical chemistry. When 1-(benzylseleno)-5-hexyl (phenyltelluro)formate (44) was thermolysed under these conditions, 2-methylselenane (45) was observed as the sole selenium-containing product, demonstrating the synthetic utility of (aryltelluro)formates as alkyl radical precursors.
- Lucas, Mathew A.,Schiesser, Carl H.
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p. 5754 - 5761
(2007/10/03)
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- Perfluoroalkyl-Chalcogenation of Alkynes
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Perfluoroalkyl-telluration of alkynes has been performed by a (PhTe)2-NaBH4-RfX system at a low temperature (-40, -80, or -100 deg C) to give 2-(perfluoroalkyl)vinyl tellurides.Meanwhile, perfluoroalkyl-sulfenylation and perfluoroalkyl-selenation were les
- Ueda, Yasufumi,Kanai, Masatomi,Uneyama, Kenji
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p. 2273 - 2277
(2007/10/02)
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- CATALYTIC OXIDATION OF OLEFINS USING DIPHENYL DITELLURIDE
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Reaction of aliphatic olefins with tert-butyl hydroperoxide and diaryl ditellurides in the presence of sulfuric acid in refluxing methanol gave methoxytellurenylation products with high regioselectivity having the aryltelluro group on the terminal carbon in the case of terminal olefins.The stereochemistry of the product from cyclohexene was trans.Under similar conditions, aromatic substituted olefins afforded vic-dimethoxyl compounds in the presence of catalytic amount of diaryl ditelluride.In this reaction, molecular oxygen (or air) as well as peroxidesand peracids were found to be effective as the oxidizing agent.The catalytic oxidation of olefins reported here proceeded in net syn fashion probably via anti methoxytellurenylation followed by displacement of the phenyltelluro group by a methoxy group with inversion.
- Kambe, Nobuaki,Fujioka, Toyozo,Ogawa, Akiya,Miyoshi, Noritaka,Sonoda, Noboru
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p. 167 - 176
(2007/10/02)
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- NUCLEOPHILIC CLEAVAGES OF ESTERS AND ETHERS WITH PHENYLTELLUROTRIMETHYLSILANE
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The title tellurosilane 1 reacted with esters and ethers in the presence of catalytic zinc iodide under very mild conditions, giving the corresponding products with C-telluration and O-silylation via nucleophilic cleavages of the C-O bonds.
- Sasaki, Kazuaki,Aso, Yoshio,Otsubo, Tetsuo,Ogura, Fumio
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p. 453 - 456
(2007/10/02)
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- PHOTOSTIMULATED REACTIONS OF 1-IODOADAMANTANE AND IODOBENZENE WITH THIOLATE, SELENATE, AND TELLURATE IONS
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The photostimulated reaction of 1-iodoadamantane (1-IAd) with benzenethiolate ion gave the substitution product 1-adamantylphenylsulfide.With benzeneselenate ion (PhSe-) it gave three products: diphenylselenide, 1-adamantylphenylselenide and di(1-adamantyl) selenide.With benzenetellurate ions it gave the substitution product 1-adamantylphenyltelluride and diphenyltelluride, the latter is ascribed to the photodecomposition of the nucleophile.The photostimulated reaction of 1-IAd with 1-naphtaleneselenate ion only gave the substitution product without scrambling of products.The photostimulated reaction of PhI with 1-adamantaneselenate ion gave the same three products as the reaction of 1-IAd and PhSe- ion, but with different ratios of products.The reaction with 1-adamantanetellurate ion gave mainly diphenyltelluride, together with the substitution product 1-adamantylphenyltelluride.The relationship of the fragmentation rates of Ad-Z and Ph-Z bonds in radical anions of structure (1-AdZPh). were studied, and kfAdZ/kfPhZ, being Z=S is 3.7, Z=Se is 9.5 and Z=Te is 13.These results suggest that in the photostimulated reactions the products obtained depend on the energy levels of the antibonding ?* MO and the ?* MO of the C-Z(Z=S, Se and Te) bonds of the radical anion intermediate.The fragmentation rates of the radical anion intermediates depend on the energy levels of the MO'S involved.
- Palacios, Sara M.,Alonso, Ruben A.,Rossi, Roberto A.
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p. 4147 - 4156
(2007/10/02)
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- Potential Pancreatic Imaging Agents. Tellurium-123m Labeled DL-α-Amino-γ-(phenyltelluro)butyric Acid
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This report describes the first successful preparation of a 123mTe-labeled α-amino acid as a potential pancreatic imaging agent.Tellurium-123m labeled DL-α-amino-γ-(phenyltelluro)butyric acid was prepared by basic hydrolysis of the radiolabeled 5-β-(phen
- Knapp, Furn F.,Ambrose, Kathleen R.,Callahan, Alvin P.
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p. 794 - 797
(2007/10/02)
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