- (5,8)Picenophanedienes: Syntheses, Structural Analyses, Molecular Dynamics, and Reversible Intramolecular Structure Conversion
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This study presents an important and efficient synthetic approach to 5,8-dibromo-2,11-di-tert-butylpicene (3), with multigram scale, which was then converted to a new series of picenophanes (6-10). The tub-shaped [2,2](5,8)picenophanediene 8 with two cis-ethylene linkers was explored using X-ray crystallography. The tub-to-tub inversion proceed through the successive bending of the linkers and the barrier for isopropyl-substituted derivative 10 was experimentally estimated to be 18.7 kcal/mol. Picenophanes with a large π-system and semi-rigid structure exhibited anomalous photophysical properties. The ethano-bridged picenophane shows the weak exciton delocalization while the cis-ethylene-bridged picenophane exhibits dual emission rendered by the weakly delocalized exciton and excimer. With the aid of the ultrafast time-resolved emission spectroscopy, the mechanism of the excimer formation is resolved, showing a unique behavior of two-state reversible reaction with fast structural deformation whose lifetime is around 20 ps at 298 K. This work demonstrates that the slight difference in the bridge of tub-shaped picenophanes renders distinct photophysical behavior, revealing the potential of harnessing inter-moiety reaction in the picenophane systems.
- Tang, Min-Chih,Wei, Yu-Chen,Chu, Yen-Chen,Jiang, Cai-Xin,Huang, Zhi-Xuan,Wu, Chi-Chi,Chao, Tzu-Hsuan,Hong, Pei-Hsun,Cheng, Mu-Jeng,Chou, Pi-Tai,Wu, Yao-Ting
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supporting information
p. 20351 - 20358
(2020/12/23)
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- Cross-coupling strategy for the synthesis of diazocines
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Ethylene bridged azobenzenes are novel, promising molecular switches that are thermodynamically more stable in the (Z) than in the (E) configuration, contrary to the linear azobenzene. However, their previous synthetic routes were often not general, and yields were poorly reproducible, and sometimes very low. Here we present a new synthetic strategy that is both versatile and reliable. Starting from widely available 2-bromobenzyl bromides, the designated molecules can be obtained in three simple steps.
- Eleya, Nadi,Li, Shuo,Staubitz, Anne
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supporting information
p. 1624 - 1627
(2020/03/13)
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- INTEGRIN ANTAGONISTS
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The present disclosure provides pharmaceutical agents, including those of the formula:(I) wherein the variables are defined herein. Also provided are pharmaceutical compositions, kits and articles of manufacture comprising such pharmaceutical agents. Meth
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Page/Page column 122-123
(2018/08/03)
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- Organic compound with tetrahedral-like geometry
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An organic compound with a tetrahedral-like geometry is disclosed. The organic compound has a structure represented by formula (I): wherein A1 to A4 each independently represent a 5-membered or 6-membered unsaturated ring; B1 represents direct bonding, —C—, —O—, —N—, —S— or —C═C—; m is 0 or 1; each of Ra's is independently hydrogen, fluorine, oxygen, substituted or unsubstituted C1-C12 alkyl or substituted or unsubstituted C6-C12 aryl; and n is an integer of 0 to 2.
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Page/Page column 34; 36
(2018/03/25)
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- Organic compound having tetrahedron-like configuration
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The present invention relates to an organic compound having a tetrahedron-like configuration, wherein the organic compound has a structure represented by the following general formula (I) defined in the specification, A1-A4 are respectively and independently an unsaturated five-membered ring or an unsaturated six-membered ring, B is a direct bond , -C, -O-, -N-, -S-, or -C=C-, m is 0 or 1, Ris hydrogen, fluorine, substituted or unsubstituted C1-C12 alkyl, or substituted or unsubstituted C6-C12 aryl, and n is an integer of 0-2. The organic compound of the present invention has excellentphotoelectric property.
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Paragraph 0087; 0089; 0090
(2018/07/07)
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- The synthesis of lactone-bridged 1,3,5-triphenylbenzene derivatives as pi-expanded coumarin triskelions
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Two triply lactone-bridged 1,3,5-triphenylbenzene derivatives with solubilizing moieties have been synthesized in five and six steps from commercially available starting materials. Compounds containing the 1,3,5-triphenylbenzene core with two atom bridges are relatively unknown. This new class of pi-expanded coumarins contain triskelion architectures and X-ray crystallographic studies of one of the triskelions indicates that the 1,3,5-triphenylbenzene core adopts a near-planar geometry. This is the only known example of a two atom-bridged 1,3,5-triphenylbenzene derivative to adopt a planar structure.
- Hintz, Heather A.,Sortedahl, Nicholas J.,Meyer, Samantha M.,Decato, Daniel A.,Dahl, Bart J.
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supporting information
p. 4703 - 4708
(2017/11/17)
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- Synthesis and Photophysical Properties of a 13,13′-Bibenzo[b]perylenyl Derivative as a π-Extended 1,1′-Binaphthyl Analog
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A 13,13′-bibenzo[b]perylenyl derivative-an axially chiral π-extended compound in which two perylene subunits fused to 1,1′-binaphthyl scaffold-has been synthesized from 1,8-dibromophenanthrene using an anionic cyclodehydrogenation reaction in the presence
- Uchida, Yosuke,Hirose, Takashi,Nakashima, Takuya,Kawai, Tsuyoshi,Matsuda, Kenji
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supporting information
p. 2118 - 2121
(2016/06/01)
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- Synthesis of dilactone bridged terphenyls with crankshaft architectures
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Three highly fluorescent dilactone bridged terphenyls with crankshaft architectures have been synthesized. This general class of compounds is relatively unexplored. These compounds have been characterized by fluorescence and UV-vis spectroscopy. For all three compounds, a direct correlation between the rigidity of the terphenyl system and the strength of absorption and emission of light has been observed. Preliminary studies have indicated that compounds with this architecture have the potential to be useful as pH-driven molecular switches and/or sensors with instant fluorescence attenuation at high pH values.
- Dressler, Justin J.,Miller, Sarah A.,Meeuwsen, Brian T.,Riel, Asia Marie S.,Dahl, Bart J.
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supporting information
p. 283 - 292
(2015/02/02)
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- Asymmetric hydrogenation of ketones with H2 and ruthenium catalysts containing chiral tetradentate S2N2 ligands
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Getting more for less: In the presence of H2 and a base, air- and moisture-tolerant RuII complexes catalyze the hydrogenation of ketones and aldehydes with excellent activity and chemoselectivity, and with enantioselectivity of up to 95 % under mild conditions. The ratio of substrate to catalyst can be lowered to 106:1. The reactions tolerate scale-up and can be carried out with almost no solvent. A base-free method is available for base-sensitive substrates. Copyright
- Patchett, Ruth,Magpantay, Iris,Saudan, Lionel,Schotes, Christoph,Mezzetti, Antonio,Santoro, Francesco
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supporting information
p. 10352 - 10355
(2013/10/21)
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- Copper-catalyzed recycling of halogen activating groups via 1,3-halogen migration
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A Cu(I)-catalyzed 1,3-halogen migration reaction effectively recycles an activating group by transferring bromine or iodine from a sp2 to a benzylic carbon with concomitant borylation of the Ar-X bond. The resulting benzyl halide can be reacted in the same vessel under a variety of conditions to form an additional carbon-heteroatom bond. Cross-over experiments using an isotopically enriched bromide source support intramolecular transfer of Br. The reaction is postulated to proceed via a Markovnikov hydrocupration of the o-halostyrene, oxidative addition of the resulting Cu(I) complex into the Ar-X bond, reductive elimination of the new sp3 C-X bond, and final borylation of an Ar-Cu(I) species to turn over the catalytic cycle.
- Grigg, R. David,Van Hoveln, Ryan,Schomaker, Jennifer M.
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supporting information
p. 16131 - 16134,4
(2020/09/09)
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- Mono-indenyl transition metal compounds and polymerization therewith
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This invention relates to transition metal compounds, catalyst sytems comprising said compounds and polymerization processes using such catalyst systems, where the transition metal compound is represented by the formula: or This invention also relates to process to produce such compounds.
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Paragraph 0241
(2013/03/26)
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- Mono-Indenyl Transition Metal Compounds and Polymerization Therewith
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This invention relates to transition metal compounds, catalyst systems comprising said compounds and polymerization processes using such catalyst systems, where the transition metal compound is represented by the formula: This invention also relates to process to produce such compounds.
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- Environmentally benign electrophilic and radical bromination 'on water': H2O2-HBr system versus N-bromosuccinimide
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A H2O2-HBr system and N-bromosuccinimide in an aqueous medium were used as a 'green' approach to electrophilic and radical bromination. Several activated and less activated aromatic molecules, phenylsubstituted ketones and styrene were efficiently brominated 'on water' using both systems at ambient temperature and without an added metal or acid catalyst, whereas various non-activated toluenes were functionalized at the benzyl position in the presence of visible light as a radical activator. A comparison of reactivity and selectivity of both brominating systems reveals the H2O2-HBr system to be more reactive than NBS for benzyl bromination and for the bromination of ketones, while for electrophilic aromatic substitution of methoxy-substituted tetralone it was higher for NBS. Also, higher yields of brominated aromatics were observed when using H2O2-HBr 'on water'. Bromination of styrene reveals that not just the structure of the brominating reagent but the reaction conditions: amount of water, organic solvent, stirring rate and interface structure, play a key role in defining the outcome of bromination (dibromination vs bromohydroxylation). In addition, mild reaction conditions, a straightforward isolation procedure, inexpensive reagents and a lower environment impact make aqueous brominating methods a possible alternative to other reported brominating protocols.
- Podgor?ek, Ajda,Stavber, Stojan,Zupan, Marko,Iskra, Jernej
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experimental part
p. 4429 - 4439
(2009/10/09)
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- Contrasting chemoselectivities in the ultrasound and microwave assisted bromination reactions of substituted alkylaromatics with N-bromosuccinimide
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Ultrasound and microwave assisted bromination reactions of various alkylaryls with N-bromosuccinimide, either neat or in water, shows diverse chemoselectivity. Thus, ring substitution occurs in water with ultrasound, whereas with microwaves both side-chain α-bromination and ring substitution occur. With neat reactants, side-chain α-bromination predominates for microwave assisted reactions. In the presence of water the chemoselectivity with microwave-promoted bromination is similar to that observed using classical methods.
- Heropoulos, Georgios A.,Cravotto, Giancarlo,Screttas, Constantinos G.,Steele, Barry R.
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p. 3247 - 3250
(2008/02/02)
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- Visible light induced 'on water' benzylic bromination with N-bromosuccinimide
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Benzylic bromination of various 4-substituted toluenes (Me, tert-Bu, COOEt and COMe) was effectively conducted with NBS in pure water and with a 40 W incandescent light-bulb as an initiator of the radical chain process, while electron donating groups (OMe and NHAc) directed the reaction to electrophilic aromatic substitution.
- Podgor?ek, Ajda,Stavber, Stojan,Zupan, Marko,Iskra, Jernej
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p. 1097 - 1099
(2007/10/03)
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- Phenacenes: A family of graphite ribbons. Part 3: Iterative strategies for the synthesis of large phenacenes
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Iterative strategies are reported for the synthesis of some large monodisperse [n]phenacenes, which are polycyclic aromatic hydrocarbon derivatives having n benzene rings fused in an extended phenanthrene-like structural motif. The key carbon-carbon bond-
- Mallory, Frank B,Butler, Kelly E,Bérubé, Amélie,Luzik Jr., Eddie D,Mallory, Clelia W,Brondyke, Emilie J,Hiremath, Rupa,Ngo, Phung,Carroll, Patrick J
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p. 3715 - 3724
(2007/10/03)
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- Structure-based design and synthesis of substituted 2-butanols as nonpeptidic inhibitors of HIV protease: Secondary amide series
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The design, synthesis, and crystallographic analysis of protein- inhibitor complexes is described for a novel series of nonpeptidic HIV protease (HIV Pr) inhibitors. Beginning with a cocrystal structure of a Phe- Pro peptidomimetic bound to the HIV Pr, design was initiated that resulted in the substituted 2-butanol compound 8 as the lead compound (K(i) = 24.5 μM, racemic mixture). Modifications on the initial compound were then made on the basis of its cocrystal structure with HIV Pr and inhibition data, resulting in compounds with enhanced potency against the enzyme (compound 18, K(i) = 0.48 μM). These inhibitors were found to bind to the enzyme essentially as predicted on the basis of the original design hypothesis. Stereospecific synthesis of individual enantiomers confirmed the prediction of a binding preference for the S alcohol stereochemistry. Modest antiviral activity was demonstrated for several of the more potent HIV Pr inhibitors in a HIV-1 infected CEM-SS cell line.
- Reich, Siegfried H.,Melnick, Michael,Pino, Mark J.,Fuhry, Mary Ann M.,Trippe, Anthony J.,Appelt, Krzysztof,Davies II, Jay F.,Wu, Bor-Wen,Musick, Linda
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p. 2781 - 2794
(2007/10/03)
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