- Solvatochromic properties of long alkyl chain π* indicators: Comparison of N/N-dialkyl-4-nitroanilines and alkyl 4-nitrophenyl ethers
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Hydrophobic forms of the N/N-dialkyl-4-nitroaniline (DNAP) (p-O 2NC6H4NR2) (1a-f) and alkyl-4-nitrophenyl ether (p-O2NC6H4OR) (2a-c) solvatochromic π* indicators have been charac
- Helburn,Bartoli,Pohaku,Maxka,Compton,Creedon,Stimpson
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Read Online
- The effect of position of (S)-2-octyloxy tail on the formation of frustrated blue phase and antiferroelectric phase in Schiff base liquid crystals
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Two series of chiral salicylaldimine-based liquid crystals which differ from each other in the position of the (S)-2-octyloxy tail have been synthesized and characterized by polarizing optical microscopy, differential scanning calorimetry, and electrical
- Huang, Chiung-Cheng,Hsu, Ching-Chung,Chen, Li-Wen,Cheng, Yu-Lun
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Read Online
- Selective Functionalization of Graphene at Defect-Activated Sites by Arylazocarboxylic tert-Butyl Esters
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The development of versatile functionalization concepts for graphene is currently in the focus of research. Upon oxo-functionalization of graphite, the full surface of graphene becomes accessible for C?C bond formation to introduce out-of-plane functional
- Halbig, Christian E.,Lasch, Roman,Krüll, Jasmin,Pirzer, Anna S.,Wang, Zhenping,Kirchhof, Jan N.,Bolotin, Kirill I.,Heinrich, Markus R.,Eigler, Siegfried
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supporting information
p. 3599 - 3603
(2019/02/01)
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- Synthesis of N-Substituted Iminosugar Derivatives and Evaluation of Their Immunosuppressive Activities
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It is important to find more effective and safer immunosuppressants, because clinically used immunosuppressive agents have significant side effects. A series of N-substituted iminosugar derivatives were designed and synthesized, and their immunosuppressive effects were evaluated by the CCK-8 assay. The results revealed that iminosugars 10 e and 10 i, that is, (3R,4S)-1-(4-heptyloxylphenylethyl)pyrrolidine-3,4-diol and (3R,4S)-1-[2-(2-chloro-4-(p-tolylthio)-phenyl-1-yl)ethyl]pyrrolidine-3,4-diol, respectively, exhibited the strongest inhibitory effects on mouse splenocyte proliferation (IC50=2.16 and 2.48 μm, respectively), whereas the iminosugars containing an amide group near the hydrophilic head (compounds 10 j–n) exhibited no inhibitory effects. Further studies revealed that the inhibitory effects on splenocyte proliferation may have come from the suppression of both IFN-γ and IL-4 cytokines. Our results suggest that synthetic iminosugars, especially compounds 10 e and 10 i, hold potential as immunosuppressive agents.
- Lv, Zhuo,Song, Chengcheng,Niu, Youhong,Li, Qin,Ye, Xin-Shan
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supporting information
p. 338 - 351
(2018/02/27)
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- Synthesis, crystal structure and DFT studies of N-[4-(Heptyloxy)phenyl]-4-methylpyrimidin-2-amine
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The compound N-[4-(heptyloxy)phenyl]-4-methylpyrimidin-2-amine with the molecular formula C18H25N3O was synthesized and recrystallized from CH3OH. The compound was characterized by 1H NMR, MS, HRMS and X-ray diffraction. The compound crystallized in the monoclinic space group P2(1)/c with a = 9.426 (2), b = 14.434 (3), c = 12.884 (3) ?, α = 90, β = 93.779 (3), γ = 90°, V = 1749.2 (6) ?3, Z = 4 and R = 0.0402 for 1798 observed reflections with I > 2σ(I). Theoretical calculation of the title compound was carried out with B3LYP/6-31G (d, p). The full geometry optimization was carried out using 6-31G (d, p) basis set and the frontier orbital energy. The optimized geometric bond lengths and bond angles obtained by using DFT(B3LYP) show the best agreement with the experimental data.
- Wu, Lei-Ting,Sun, Na-Bo,He, Fang-Yue
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p. 7397 - 7400
(2015/04/22)
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- Liquid crystalline properties of dimers having o-, m- and p- positional molecular structures
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With the objective to design and synthesis of Schiff's base symmetrical liquid crystal dimmers and to study the effect of molecular structure variation (o-ortho, m-meta, p-para) and change in alkoxy terminal chain length on mesomorphic properties of liquid crystals, We have synthesized Schiff base dimers from dialdehyde derivative containing 2-hydroxy-1,3-dioxypropylene as short spacer with aniline derivatives having different lengths of terminal alkoxy chains (n = 5, 7, 9). The chemical structure of the final products was characterized by proton nuclear magnetic resonance (1H NMR) spectroscopy and fourier transform infrared (FT-IR) spectroscopy. The mesomorphic properties and optical textures of the resultant dimers were characterized by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The existence of smectic A phase transition was confirmed by the observation of batonnets and fan shaped textures in optical microscopy when compound were heated from crystalline phase. All of the dimers of this series, with the exception of 2S5 -ortho, -meta, -para, were thermotropic liquid crystal. The compound 2S9 -meta was monotropic, while the rest were enantiotropic. It was found that the change in terminal alkoxy chain length has pronounced effect on the mesomorphic properties. The temperature range of smectic A phase window widens with increasing alkoxy chain length.
- Park, Joo-Hoon,Choi, Ok-Byung,Lee, Hwan Myung,Lee, Jin-Young,Kim, Sung-Jo,Cha, Eun-Hee,Kim, Dong-Hyun,Ramaraj,So, Bong-Keun,Kim, Kyung-Hwan,Lee, Soo-Min,Yoon, Kuk Ro
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experimental part
p. 1647 - 1652
(2012/07/27)
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- Liquid-crystalline polymorphism of 4-heptyloxybenzylidene-4′- alkyloxyanilines and their phase equilibrium with 4-octyloxyphenyl 4-nitrobenzoate
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This paper describes the synthesis and liquid-crystalline properties of the homologous series of 4-heptyloxybenzylidene-4′-alkyloxyanilines (7-n). Six of them are presented for the first time. Based on the polarization microscopy (POM and TOA methods) and the calorimetric (DSC) measurements following polymorphism has been detected: nematic, smectic C and smectic I mesophases. The presence of these mesophases was confirmed by the miscibility method, using 4-octyloxyphenyl 4-nitrobenzoate and terephtal-bis (4-butyloaniline) as a mesophase references. Extraordinary results have been found in the mixtures of the investigated compounds with 4-octyloxyphenyl 4-nitrobenzoate; Induced smectic A has been observed, which is connected with very strong intermolecular interactions. Additionally destabilization of nematic and smectic C phases was visible.
- Godzwon, Joanna,Sienkowska, Monika J.,Galewski, Zbigniew
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scheme or table
p. 75 - 82
(2012/04/04)
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- Synthesis of alkyl-aryl ethers by copper-catalyzed etherization reactions of aryl fluorides with tetraalkylammonium bromides and H2O
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Synthesis of alkyl aryl ethers via copper-catalyzed etherizations of electron-deficient aryl fluorides with quaternary ammonium bromides and water has been developed. In the presence of Cu(OAc)2, POPh3 (L4) and Cs2CO3, a variety of electron-deficient aryl fluorides underwent the reaction with quaternary ammonium bromides and H 2O in moderate to good yields. The mechanism was also discussed. Synthesis of alkyl aryl ethers via copper-catalyzed etherizations of electron-deficient aryl fluorides with quaternary ammonium bromides and water has been developed. In the presence of Cu(OAc)2, POPh3 (L4) and Cs2CO3, a variety of electron-deficient aryl fluorides underwent the reaction with quaternary ammonium bromides and H 2O in moderate to good yields. Copyright
- Wang, Feng,Tang, Boxiao,Xie, Yexiang,Li, Jinheng
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experimental part
p. 2318 - 2322
(2011/10/03)
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- Synthesis of symmetric liquid crystal dimers based on azo and imine groups and investigation of phase behaviour by varying alkoxy terminal chain length
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With the objective to study the effect of alkoxy terminal chain length on mesomorphic properties of liquid crystals, we have synthesized two (Azo and Imine) different series of dimesogens by varying terminal alkoxy chain length (n = 6-12) with a short spacer unit in between two mesogens. Transition temperatures and phase characterization were studied by DSC, POM and XRD analysis. It was found that all the dimers show mesomorphic properties and the change in terminal alkoxy chain length has pronounced effect on the smectic phase window. In the DSC cooling scan, the smectic phase window of azo compounds increased from 6.4°C (2A6) to 16.0°C(2A12), whereas in Schiff base compounds, it increased from 9.2°C (2S6) to 31.0°C(2S12). Further, the 2A11 dimer was found to undergo photo induced configurational changes.
- Kim, Tae Hyeong,Lee, Chang Sin,Ramaraj,Jeon, Hye Jin,Song, Hyun Hoon,Lee, Soo Min,Yoon, Kuk Ro
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experimental part
p. 102 - 116
(2010/03/04)
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- Synthesis and liquid crystalline properties of novel triazene-1-oxide derivatives
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A new group of compounds, C6H5-N(O)=N-NH-C6H4-C(O)-O-C6H4-CH=N-C6H4-OR, (1), [R=n-alkyl group; 1a (R=C7H15 ) to 1h (R=C14H29)], has been designed and synthesized to develop triazene-1-oxide based liquid crystals. All the compounds have been characterized on the basis of their spectral data. Their thermal behavior has been examined and found to exhibit thermotropic liquid crystalline behavior over a wide range of temperature. All members of this family uniformly show nematic phase behavior on melting up to the clearing point during heating as well as on phase entering up to the solidification during cooling. An odd-even effect on transition temperatures has been observed during heating as well as cooling.
- Das, Purak,Biswas, Achintesh Narayan,Bandyopadhyay, Pinaki,Mandal, Pradip Kumar
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scheme or table
p. 3 - 15
(2010/03/24)
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- Smectic polymorphism of 4-nonyloxybenzylidene-4′-alkyloxyanilines
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This paper describes liquid-crystalline polymorphism of the homologous series of 4-nonyloxybenzylidene-4′-alkyloxyanilines. Based on the polarization microscopy (POM, TOA) and the calorimetric (DSC) measurements the following mesophases were detected: nematic, smectic A, smectic C, smectic B, smectic I and smectic G. The presence of these mesophases was confirmed by the miscibility method, using: 4-heptyloxybenzilidene-4′-pentylaniline, 4-hexyl-4′-decyloxyazobenzene and 4-nonyloxybenzilidene-4′-butylaniline as mesophase references. Influence of the alkyl chain length on the type of mesophases and entropic effects of phase transition are discussed.
- Godzwon, Joanna,Sienkowska, Monika J.,Galewski, Zbigniew
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p. 259 - 267
(2008/03/13)
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- Organosoluble copper clusters as precatalysts for carbon - Heteroelement bond-forming reactions: Microwave and conventional heating
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(Chemical Equation Presented). The coupling of aryl iodides with alcohols under mild conditions has been explored using self-assembled octanuclear copper clusters as catalysts. Reactions involving tetrahydrofurfuryl alcohol were typically complete in 4-8
- Manbeck, Gerald F.,Lipman, Adam J.,Stockland Jr., Robert A.,Freidl, Adrienne L.,Hasler, Amy F.,Stone, Joshua J.,Guzei, Ilia A.
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p. 244 - 250
(2007/10/03)
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- The newborn surface of dull metals in organic synthesis. Bismuth-mediated solvent-free one-step conversion of nitroarenes to azoxy- and azoarenes
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When milled together with bismuth shots, nitroarenes are readily converted to azoxy- and/or azoarenes depending on substrates and conditions employed. Simple extraction with organic solvent followed by evaporation of the resulting dark pasty solid gave the product in good yield.
- Wada, Shinobu,Urano, Mika,Suzuki, Hitomi
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p. 8254 - 8257
(2007/10/03)
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