- Porous Self-Assembled Molecular Networks as Templates for Chiral-Position-Controlled Chemical Functionalization of Graphitic Surfaces
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Controlled covalent functionalization of graphitic surfaces with molecular scale precision is crucial for tailored modulation of the chemical and physical properties of carbon materials. We herein present that porous self-assembled molecular networks (SAMNs) act as nanometer scale template for the covalent electrochemical functionalization of graphite using an aryldiazonium salt. Hexagonally aligned achiral grafted species with lateral periodicity of 2.3, 2.7, and 3.0 nm were achieved utilizing SAMNs having different pore-to-pore distances. The unit cell vectors of the grafted pattern match those of the SAMN. After the covalent grafting, the template SAMNs can be removed by simple washing with a common organic solvent. We briefly discuss the mechanism of the observed pattern transfer. The unit cell vectors of the grafted pattern align along nonsymmetry axes of graphite, leading to mirror image grafted domains, in accordance with the domain-specific chirality of the template. In the case in which a homochiral building block is used for SAMN formation, one of the 2D mirror image grafted patterns is canceled. This is the first example of a nearly crystalline one-sided or supratopic covalent chemical functionalization. In addition, the positional control imposed by the SAMN renders the functionalized surface (homo)chiral reaching a novel level of control for the functionalization of carbon surfaces, including surface-supported graphene.
- Brown, Anton,Feyter, Steven De,Hashimoto, Shingo,Hirsch, Brandon E.,Ishikawa, Toru,Kaneko, Hiromasa,Kubo, Yuki,Tahara, Kazukuni,Tobe, Yoshito
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- Syntheses of female sex pheromone precursors of pine sawfly species and of some structurally related methyl-branched long-chain 2-alkanols.
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3,7-Dimethyl-2-undecanol, 3,7,9-trimethyl-2-tridecanol, and 3,7, 11-trimethyl-2-tridecanol were synthesized as racemic mixtures in moderate yields. The alcohols are known precursors of the female sex pheromones of the pine sawfly species Diprion nipponica, Macrodiprion nemoralis, and Microdiprion pallipes, respectively. Stereoisomeric mixtures of 3,8,12-trimethyl-2-tridecanol, erythro-(2R,3R, 11R/S)-3,11-dimethyl-2-tetradecanol, 3,5-dimethyl-2-tetradecanol, and 5,7-dimethyl-2-tetradecanol, structurally related to sex pheromone alcohol precursors of pine sawfly species, were also synthesized in moderate yields. The key reaction in the syntheses was the ring opening of gamma-butyrolactones by using different alkyl lithiums as nucleophiles.
- Hedenstroem, Erik,Andersson, Fredrik
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- COMPOUND HAVING BRANCHED ALKYL OR BRANCHED ALKENYL, OPTICALLY ISOTROPIC LIQUID CRYSTAL MEDIUM AND OPTICAL ELEMENT
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The first object of the invention is to provide a liquid crystal compound that is stable to heat, light and so on, and has a large optical anisotropy, a large dielectric anisotropy and a low melting point. The second object is to provide a liquid crystal medium that is stable to heat, light and so on, has a broad temperature range of a liquid crystal phase, a large optical anisotropy and a large dielectric anisotropy, and exhibits an optically isotropic liquid crystal phase. The third object is to provide a variety of optical elements containing the liquid crystal medium, which can be used in a broad temperature range and has a short response time, a high contrast and a low driving voltage. A liquid crystal compound with branched alkyl or branched alkenyl as represented by formula (1), a liquid crystal medium (a liquid crystal composition or a polymer/liquid crystal composite material) containing the liquid crystal compound, and an optical element containing the liquid crystal medium are described. In formula (1), R1 is branched alkyl of C3-20 or branched alkenyl of C3-20. The ring A1, A2, A3, A4 or A5 is 1,4-phenylene or 1,3-dioxane-2,5-diyl, for example. Z1, Z2, Z3 and Z4 are independently a single bond or C1-4 alkylene, for example. Y1 is fluorine, for example, m, n and p are independently 0 or 1, and 1≤m+n+p≤3.
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Paragraph 0304; 0307
(2013/05/09)
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- Stereochemical investigations reveal the mechanism of the bacterial activation of n-alkanes without oxygen
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Anaerobic growth of the bacterium strain HxN1 with n-hexane gives nearly equal amounts of (2R,1 R)- and (2S,1 R)-(1-methylpentyl)succinate, which are formed by the radical addition of the hydrocarbon to fumarate (see scheme). The highly selective attack on the pro-S hydrogen atom at C2 of n-hexane is associated with inversion of the configuration at C2 during binding to fumarate and exhibits isotopic discrimination against a C-2H bond. Copyright
- Jarling, Rene,Sadeghi, Masih,Drozdowska, Marta,Lahme, Sven,Buckel, Wolfgang,Rabus, Ralf,Widdel, Friedrich,Golding, Bernard T.,Wilkes, Heinz
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p. 1334 - 1338
(2012/03/27)
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- Do enzymes recognise remotely located stereocentres? Highly enantioselective Candida rugosa lipase-catalysed esterification of the 2- to 8-methyldecanoic acids
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Several racemic methyl decanoic acids have been synthesised and successfully resolved in esterification with 1-hexadecanol at aw=0.8 in cyclohexane using immobilised Candida rugosa lipase (CRL) as the catalyst. The enantiomeric ratios (E=2.8-68) obtained were surprisingly high even when the methyl group was as remotely located as in 8-methyldecanoic acid (E=25). Interestingly, the lipase shows enantiopreference for the S-enantiomer when the methyl group is located on even numbered carbons i.e. for the 2-,4-,6- and 8-methyldecanoic acids and to the R-enantiomer when the methyl group is located on uneven numbered carbons i.e. for the 3-,5- and 7-methyldecanoic acids.
- Hedenstroem, Erik,Nguyen, Ba-Vu,Silks III, Louis A.
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p. 835 - 844
(2007/10/03)
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- Regio- and stereochemical study of sex pheromone of pine sawfly; Diprion nipponica
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Regio- and stereoisomers of 1,2,ω-trimethyldecyl propionate (ω = 5-9) were prepared from stereochemically pure chiral building blocks as sex pheromone candidates of a pine sawfly; Diprion nipponica. Among the synthesized candidates, (1S,2R,8S)-1,2,8-trimethyldecyl propionate was found to be the sex pheromone of D. nipponica, based on compatibility of its GC-MS data with that of the extract of females, and its significantly high pheromone activity in a field bioassay. The field bioassay of the synthesized compounds also revealed that (1S,2R,SR)-1,2,8-trimethyldecyl propionate, (1S,2R,7S)-1,2,7-trimethyldecyl propionate, and (1S,2R,6S)-1,2,6-trimethyldecyl propionate could attract male sawflies to some extent as pheromone mimics.
- Tai, Akira,Syouno, Emi,Tanaka, Kazuki,Fujita, Morifumi,Sugimura, Takashi,Higashiura, Yasutomo,Kakizaki, Masashi,Hara, Hideho,Naito, Tikahiko
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p. 111 - 121
(2007/10/03)
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- Pheromone synthesis, CXCII. - Synthesis of all the stereoisomers of 10,14-dimethyloctadec-1-ene, 5,9-dimethyloctadecane and 5,9- dimethylheptadecane, the sex pheromone components of the apple leafminer, Lyonetia prunifoliella
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All of the stereoisomers of 10,14-dimethyloctadec-1-ene (1), 5,9- dimethyloctadecane (2) and 5,9-dimethylheptadecane (3), the sex pheromone components of the apple leafminer (Lyonetia prunifoliella), were synthesized by starting from the enantiomers of ci
- Tamagawa, Hideki,Takikawa, Hirosato,Mori, Kenji
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p. 973 - 978
(2007/10/03)
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- Exo- and endohormones. XVII: Synthesis of racemic 5,9-dimethyl-heptadecane, the sex pheromone for the leafminer moth Leucoptera scitella
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The paper describes two practical syntheses of 5,9-dimethyl-heptadecane, the sex pheromone of the leafminer moth Leucoptera scitella (Lepidoptera, Lyonetidae). The first route (Scheme 1) involves as key reaction the coupling of 2-methyl-hexyl magnesium bromide with 3-methyl-undecanal. The second route (Scheme 3) is based on the Schlosser-Fouquet coupling reaction of 2-decyl-magnesium bromide with 4-methyl-octyl bromide.
- Ciocan-Tarta, Ilie,Oprean, Ioan,Ghizdavu, Iustin,Pojar-Fenesan, Maria
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p. 215 - 219
(2007/10/03)
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- 14C-Labeling of a novel prostacyclin I1 derivative, SM-10902
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(+)-Methyl [2-[(2R,3aS,4R,5R,6aS)-octahydro-5-hydroxy-4-[(E)(3S,5S)-3-hydroxy-5-methyl-1 -[3-14C]nonenyl]-2-pentalenyl]ethoxy]-acetate ([nonenyl-3-14C]SM-10902) (1) was labeled with carbon-14 for use in mammalian metabolic studies. The synthesis was achieved in 7 steps from [14C]carbon dioxide: including: 1) Grignard reaction, 2) esterification, 3) condensation with dimethyl methylphosphonate, 4) Wittig-Horner reaction, 5) separation of isomers by HPLC. Stereoselective reduction of the protected ketone with sodium borohydride in the presence of cerium (III) chloride and subsequent desilylation produced 1. The overall yield was 11.1% from Ba[14C]CO3.
- Kurosawa, Motohiro,Kanamaru, Hiroshi,Nishioka, Kazuhiko
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p. 129 - 138
(2007/10/03)
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- Pheromones, 89.- Wittig Syntheses of Alkyl-Branched and Cyclic Analogs of (Z)-5-Decenyl Acetate, the Sex Pheromone of Agrotis segetum (Lepitoptera: Noctuidae)
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By means of (Z)-selective Wittig olefination alkyl-branched and cyclic analogs of (Z)-5-decenyl acetate, the sex pheromone of the turnip moth, Agrotis segetum (Lepidoptera: Noctuidae), have been synthesized. Key Words: Pheromones / (Z)-5-decenyl acetate / Wittig reactions / Agrotis segetum
- Albores, Martha,Bestmann, Hans Juergen,Doehla, Bodo,Hirsch, Hans-Ludwig,Roesel, Peter,Vostrowsky, Otto
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p. 231 - 236
(2007/10/02)
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- POTENTIAL SEX PHEROMONE IN Platynereis dumerilii - IDENTIFICATION AND SYNTHESIS
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5-methyldecane (6a,b) was extracted from ripe males of Platynereis dumerilii by using a closed loop stripping technique and identified by GC-MS and synthesis.This substance is a minor component of the pheromone bouquet and elicites an electrophysiological response in females of Platynereis dumerilii.
- Zeeck, E.,Hardege, J. D.,Bartels-Hardege, H.,Wesselmann, G.
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p. 5613 - 5614
(2007/10/02)
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- 13C magnetic resonance studies. 142. The fate of highly substituted acyclic ketones in strong base: β-enolization, Haller-Bauer cleavage, and an alkyl to aryl acyl shift
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Di-tert-butyl ketone (2a), 5,5,7,7-tetramethyl-6-undecanone (2b), and 2,4-dimethyl-2,4-diphenyl-3-pentanone (2d) have been found to undergo slow rearrangement by β-proton abstraction from the α-methyl groups upon treatment with t-BuO-/t-BuOH/>185 deg C.This is in contrast to the absence of such rearrangement in cyclic systems.It is the only significant process observed for 2a and 2b, whereas with 2d and its monomethyl analog 22 Haller-Bauer type cleavage and an unprecedented 1,3-acyl shift from sp3 to sp2 carbon accompany the β-enolate rearrangement.The rates of 1H/2H exchange of the methyl protons in 2a, b were found to be similar to those reported for a variety of cyclic systems but this exchange does not occur in 2d, where only aryl proton exchange was observed.
- Dyllick-Brenzinger, Rainer A.,Patel, Vijay,Rampersad, Mollin B.,Stothers, J. B.,Thomas, Shirley E.
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p. 1106 - 1115
(2011/08/10)
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