- SYNTHESIS AND MEMBRANE ACTIVITY OF NEW DERIVATIVES OF 2,3-BENZO-18-CROWN-6
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The acylation of 2,3-benzo-18-crown-6 with carboxylic acids in the presence of polyphosphoric acid has been given new acyl derivatives which have been reduced to the corresponding alkyl derivatives.The ionophoric activities of the compounds have been investigated on mitochondrial membranes.
- Shkinev, A. V.,Asrarov, M. I.,Gagel'gans, A. I.,Saifullina, N. Zh.,Mukhamedzhanova, E. A.,Tashmukhamedova, A. K.
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- Synthesis and complexation properties of 3-Aroylcoumarin crown ethers. A new class of photoactive macrocycles
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Synthesis of fluoroionophores consisting of 3-benzoylcoumarins fused with crown ethers in two different modes are described. The resulting macrocycles bore emission properties strongly dependent on metal ions and coumarin substitution and may be therefore used as cation dependent fluorescence signaling systems or triplet sensitizers for lanthanide luminescence.
- Alonso, Maria Teresa,Brunet, Ernesto,Hernandez, Concepcion,Rodriguez-Ubis, Juan Carlos
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- Methanofullerenes and methanofulleroids have different electrochemical behavior at negative potentials
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Cathodic electrochemistry was performed for two methanofullerene derivatives, 3 and 4. Since it was possible to isolate the [6,6] closed isomeric forms of these derivatives (called simply methanofullerenes), the electrochemistry of the pure isomers was recorded. The electrochemical behavior of the corresponding mixtures, which also contained the [5,6] open forms (simply referred to as methanofulleroids), was also obtained. In the solvent mixture used, acetonitrile:toluene (1:5), no difference was observed for the potentials of the first four electrochemical waves of the two isomers. However, the methanofulleroid exhibited an anodically-shifted fifth reduction wave, relative to that corresponding to the methanofullerene. This difference in potential was 0.20 V for the fullerene-fulleroid isomers of both 3 and for those of 4. On the basis of the voltammetric data, the fulleroids behave more as triply degenerate systems, very much like the behavior for C60. This was anticipated, since they are, as is the parent C60, 60 π electron systems. However, the methanofullerenes have 58 π electrons, and part of their conjugated network is destroyed. The fullerenes exhibit what appear to be doubly degenerated LUMOs with a LUMO+ that is some 4-5 kcal/mol higher in energy. The presence of the methanofullerene was confirmed by simultaneous UV-vis spectrophotometry in the case of 3. Thermalization of isomeric mixtures of 3 and 4 resulted in the quantitative formation of the methanofullerene and the total disappearance of the methanofulleroid, consistent with previous results.
- Arias,Echegoyen,Wilson,Lu,Lu
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- Synthesis, metal ion binding, and photochromic properties of benzo- and naphthopyrans annelated by crown ether moieties
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Combining a photochromic chromene with a crown ether moiety results in systems in which photochromism and ionophoric properties could significantly influence each other. In this paper, we report the synthesis of several chromenes annelated by 15(18)-crown
- Paramonov, Sergey V.,Lokshin, Vladimir,Smolentsev, Artem B.,Glebov, Evgeni M.,Korolev, Valeri V.,Basok, Stepan S.,Lysenko, Konstantin A.,Delbaere, Stéphanie,Fedorova, Olga A.
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experimental part
p. 7873 - 7883
(2012/10/08)
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- Functionalized palladacycles with crown ether rings derived from terdentate [ C, N, N ] ligands. crystal and molecular structure of the dinuclear palladium/silver complex [Pd{3,4-(AgC10H20O 6)C6H2C(Me
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Reaction of 3,4-(C10H20O6)C 6H3C(Me)=NN(H)[3′-(CF3)C 4H2N2] (a) and 3,4-(C10H 20O6)C6H3C(Me)=NN(H)(4′
- Vazquez-Garcia, Digna,Fernandez, Alberto,Lopez-Torres, Margarita,Rodriguez, Antonio,Varela, Alexis,Pereira, M. Teresa,Vila, Jose M.,Fernandez, Jesus J.
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experimental part
p. 396 - 404
(2011/03/21)
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- Catalytic Friedel-Crafts acylation and benzoylation of aromatic compounds using activated hematite as a novel heterogeneous catalyst
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Catalytic Friedel-Crafts acylation of benzene and unactivated benzenes such as chlorobenzene and nitrobenzene have been successfully carried out using activated hematite (α-Fe2O3) as a new, heterogeneous and green catalyst. Sonication of neat α-Fe2O3 in a water bath under air atmosphere at room temperature followed by heating at 200°C, dramatically increase the activity of α-Fe2O 3. With the catalyst loading as low as 5.0mol%, a wide variety of benzene derivatives were easily converted into the corresponding acylated products in a clean and high-yielding acylation reaction. It was found that the activated α-Fe2O3 could be efficiently recycled and reused several times by simple washing with ethyl acetate, this cannot be attained with most of the traditional catalysts. Copyright
- Sharghi, Hashem,Jokar, Mahboubeh,Doroodmand, Mohammad Mahdi,Khalifeh, Reza
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experimental part
p. 3031 - 3044
(2011/02/21)
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- Synthesis of 4'-Vinylbenzo-3n-crown-n Ethers (4<=n<=10)
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4'-Vinylbenzo-3n-crown-n ethers (4=n=10) are prepared by a "Cs-templated" cyclization reaction of catechol with dimesylates of oligoethylene glycols, acetylation of the resultant benzo-3n-crown-n ethers (4=n=10), reduction of the acyl group, and dehydration of the resultant alcohols with pyridinium tosylate.
- Talma, Auke G.,Vossen, Huib van,Sudhoelter, Ernst J. R.,Eerden, Johan van,Reinhoudt, David N.
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p. 680 - 683
(2007/10/02)
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- The Synthesis of Adrenaline Crown Ethers
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The syntheses of adrenaline-15-crown-5 and adrenaline-18-crown-6 starting from acetovanillone are reported, together with the properties of these compounds.Alkali and alkaline-earth metal complexes of these ligands have been prepared.A method of separating crown ethers based on their preferential complexation of barium is discussed.
- Fenton, David E.,Parkin, Donald,Newton, Roger F.
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p. 449 - 454
(2007/10/02)
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- Photochemistry of Host-Guest Complex.III. Effect of Guest Cation on the Photoreactivity of Acetophenone Oxime Derivatives Having Crown Ether Moiety
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The syn-anti isomerisation of acetylbenzocrown ether oximes was stimulated by the complex-formation with sodium ion.The photolysis of these oximes gave mother ketones and amides through an oxaziridine intermediate.The photolysis of the oximes was depressed by the formation of host-guest complexes.Reactivity in the photolysis of the crown ether oximes corresponds to that 3,4-dimethoxyacetophenone oxime, whereas the reactivity of the complexed crown ether oxime with sodium ion corresponds to that of p-cyanoacetophenone oxime.Such behavior is explained by the change of the electronic properties of excited states of acetophenone oxime chromophore, which enhances the intersystem crossing.
- Tada, Masaru,Hirano, Hideki,Suzuki, Atsushi
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p. 2304 - 2308
(2007/10/02)
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