- Oxidative cyclotrimerization of unsaturated compounds with DDQ and triflic acid: An efficient synthetic route to triply-fused benzene rings
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Intermolecular oxidative cyclotrimerization reactions of alkenes and aromatic compounds with DDQ and trifluoromethanesulfonic acid are described. Scholl-type oxidation reactions involving alkenes have not previously been demonstrated. Moreover, the DDQ/acid system has never been used for intermolecular oxidative cyclization reactions. This convenient, metal-free reagent system (DDQ/TfOH) is advantageous with respect to metal-based Scholl-type oxidants because it eliminates the possibility of halogenation of aromatic compounds as a competing side reaction.
- Cho, Hee Yeon,Scott, Lawrence T.
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supporting information
p. 3458 - 3462
(2015/01/30)
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- Self-organization of star-shaped columnar liquid crystals with a coaxial nanophase segregation revealed by a combined experimental and simulation approach
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Fully consistent X-ray data and molecular dynamics simulations on new star-shaped liquid crystals yield two nanosegregated architectures with a coaxial stacking of two functional discotic units: tris(triazolyl)triazine and triphenylene. Analysis of lattice order along the principal axes reveals preferential staggered arrangement of the stacked molecules in the columnar assembly.
- Beltrán, Eduardo,Garzoni, Matteo,Feringán, Beatriz,Vancheri, Alberto,Barberá, Joaquín,Serrano, José Luis,Pavan, Giovanni M.,Giménez, Raquel,Sierra, Teresa
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supporting information
p. 1811 - 1814
(2015/02/05)
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- Synthesis and specific features of mesomorphic behavior of new polysubstituted triphenylenes
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Previously unknown 2,3,6,7,10,11-hexakis(dodecyloxy)triphenylene and -(tetradecyloxy)triphenylene were synthesized. The structures of the synthesized compounds were proved by elemental analysis and spectral methods. Polymesomorphism was found for the first time and studied for substances of the hexaalkoxytriphenylene homologic series, as well as liotropic mesomorphism in a series of organic solvents.
- Zemtsova,Zheleznov
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p. 1743 - 1748
(2007/10/03)
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- Synthesis of triphenylene and dibenzopyrene derivatives: Vanadium oxytrichloride a novel reagent
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This paper presents an efficient synthetic procedure for the preparation of various triphenylene and dibenzopyrene derivatives using VOC13 as a novel reagent. Symmetrically substituted hexaalkoxytriphenylenes are obtained from o-dialkoxybenzenes by oxidative trimerization with VOC13 in high yields. The oxidative coupling of a 3,3′,4,4′-tetraalkoxybiphenyl and 1,2-dialkoxybenzenes or 1,2,3-trialkoxybenzenes affords unsymmetrically substituted derivatives of triphenylene. The reagent oxidizes 3,3′,4,4′-tetraalkoxybiphenyl efficiently to 2,5,6,9,12,13-hexaalkoxydibenzo[fg, op]naphthacene-1,8-quinone and its 1,10-quinone isomer. Both the quinones can be converted to liquid crystalline derivatives using well-established chemistry. Effects of solvent, reagent concentration, acid catalyst and temperature have been studied.
- Kumar,Varshney
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p. 305 - 311
(2007/10/03)
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- Synthesis and investigation of polysubstituted triphenylenes with a predictable type of mesomorphism
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This paper reports on synthesis and investigation of columnar mesophases of the new members of the homologous series of nitro and amino derivatives of hexaalkoxytriphenylenes, whose mesomorphism was predicted earlier. The forecast is in good agreement with the experimental data. The effect of the introduction of the donor and acceptor groups into the central fragment of triphenylene on the phase transition temperature, texture, and range of existence of columnar mesophases is examined. The predicting ability of the molecular parameters suggested previously for the series under analysis is discussed. It is found that introduction of a nitro group, which is a strong electron acceptor, into the central fragment of triphenylene lowers the melting temperature of the compound versus its analog and does not promote columnar mesomorphism in the lower nonmesomorphous homologs. At the same time, this slightly expands the range of existence of the mesophase in higher homologs.
- Zemtsova,Syromyatnikova,Kotovich,Akopova
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- Polysubstituted triphenylenes with active groups. Molecular parameters, synthesis, structure, and mesomorphism
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Molecular parameters of hexaalkoxytriphenylenes with different substituents on the periphery of the triphenylene nucleus of known and hypothetical structures are calculated. The probability of a discophase for compounds of this series is estimated from molecular parameters. Several compounds of this series having polar groups (NO2, NH2) in the 1 position of the triphenylene nucleus have been synthesized. The compounds synthesized were investigated by thermopolarizing microscopy and X-ray diffraction analysis. The data on the mesomorphism of the new compounds are in good agreement with our prediction that alkoxytriphenylenes with polar groups have a discophase. It is established that introduction of an electron-accepting group at position 1 of the triphenylene nucleus expands the temperature range of existence of the discophase to room temperature. On the contrary, introduction of an electron-donating group narrows this interval. Compounds of this series presumably have a hexagonal columnar structure. 1998 Plenum Publishing Corporation.
- Akopova,Bronnikova,Kruvchinskii,Kotovich,Shabyshev,Valkova
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p. 376 - 383
(2007/10/03)
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- Oxidative trimerization of o-dialkoxybenzenes to hexaalkoxytriphenylenes: Molybdenum(v) chloride as a novel reagent
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Symmetrically substituted hexaalkoxytriphenylenes are obtained from o-dialkoxybenzenes by oxidative trimerization with MoCl5 in high yields; oxidative coupling of a 3,3′,4,4′-tetraalkoxybiphenyl and 1,2-dialkoxybenzenes yields unsymmetrically substituted derivatives of triphenylene and a direct coupling of a 3,3′,4,4′-tetraalkoxybiphenyl with alkoxyphenol produces the monofunctionalized triphenylenes.
- Kumar, Sandeep,Manickam
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p. 1615 - 1616
(2007/10/03)
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- A high yield easy method for the preparation of alkoxy-substituted triphenylenes
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2,3,6,7,10,11-Hexamethoxytriphenylene is prepared by oxidative trimerization of 1,2-dimethoxybenzene (veratrol) with iron(III) chloride/sulfuric acid in nearly quantitative yield. The obtained crude product is almost pure. Other alkoxy-substituted triphenylenes are also synthesized by this method.
- Naarmann,Hanack,Mattmer
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p. 477 - 478
(2007/10/02)
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- THE ANODIC TRIMERIZATION OF AROMATIC ORTHODIETHERS: NEW DEVELOPMENTS
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While the anodic trimerization of veratrole (leading to hexamethoxytriphenylene) is now a very well known reaction, developments concerning either mixed electrolysis (mixture of two orthodiethers) and/or oxidation of dissymmetrical substrates have not bee
- Chapuzet, Jean-Marc,Simonet, Jacques
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p. 791 - 798
(2007/10/02)
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- DISSYMMETRIC HEXASUBSTITUTED TRIPHENYLENES.
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Several dissymmetrical hexasubstituted triphenylenes were prepared exhibiting a low temperature thermotropic mesophase. It is shown that it corresponds to a columnar mesophase (an hexagonal arrangement of columns of discs). The magnetic properties of these new disc-like liquid crystals are compared with those of the corresponding symmetrical ones.
- Nguyen Huu Tinh,Bernaud,Sigaud,Destrade
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p. 307 - 314
(2007/10/02)
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