- Synthesis of substituted dibenz[a,c]anthracenes and an investigation of their liquid-crystalline properties
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We report the synthesis of a series of 2,3,5,6-tetraalkoxydibenz[ a,c]anthracenes bearing substituents (H, OCH3, or CN) in the 11- and 12-positions and an investigation of their liquid- crystalline properties. The synthesis involved Suzuki coupling of the appropriate dibromonaphthalene and boronate ester, followed by an oxidative cyclization. Compounds 4 and 5, bearing OCH3 and H, respectively, do not exhibit any liquid-crystalline properties. In contrast, compounds 6a-c, bearing cyano groups, assemble into columnar mesophases, suggesting that electron-withdrawing groups are important for promoting columnar mesophase assembly. Analysis of the XRD revealed that compound 6b exhibits a columnar hexagonal phase, whereas compounds 6a and 6c exhibit columnar rectangular phases. The XRD data of 6a and 6b also show reflections that are consistent with antiparallel dimers within the columnar stacks, and intercolumnar spacings suggest that molecules are tilted within the columns.
- Psutka, Katie M.,Williams, Joshua,Paquette, Joseph A.,Calderon, Oliver,Bozek, Kevin J.A.,Williams, Vance E.,Maly, Kenneth E.
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- The photochemical synthesis of naphtho[2,3-g]thiopheno[3,2- e]benzo[b]thiophene: A new heterocyclic system
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The synthesis is described of the hitherto unknown 2,3-bis(2'- thienyl)naphthalene (1). Photochemical cyclisation of 1 affords naphtho[2,3- g]thiopheno[3,2-e]benzo[b]thiophene (2), the parent compound of a new aromatic heterocyclic series.
- Brooks, Peter,Donati, Donato,Pelter, Andrew,Poticelli, Fabio
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- Selective Vicinal Diiodination of Polycyclic Aromatic Hydrocarbons
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Vicinally diiodinated polycyclic aromatic hydrocarbons (I2-PAHs) are accessible from the corresponding diborylated B2-PAHs through boron/iodine exchange. The B2-PAHs have been prepared via twofold electrophilic borylation reactions templated by a vicinally disilylated benzene. Our protocol is applicable to fluorenes, acenes, annulated acenes, oligoaryls, and even [5]helicene. Using B2-naphthalene as the example, we have shown that the reaction scope can, in principle, be expanded to include the synthesis of vicinally dibrominated and dihydroxylated PAHs. The usefulness of the building blocks provided by our method in the field of optoelectronic materials was demonstrated by the successful conversion of I2-fluoranthene to the analogous doubly alkynylated fluoranthene emitter.
- Bolte, Michael,Jin, Tao,John, Alexandra,Kaehler, Tanja,Lerner, Hans-Wolfram,Wagner, Matthias
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supporting information
p. 5847 - 5851
(2020/09/09)
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- Regioselective arene homologation through rhenium-catalyzed deoxygenative aromatization of 7-oxabicyclo[2.2.1]hepta-2,5-dienes
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Combined use of oxorhenium catalysts with triphenyl phosphite as an oxygen acceptor allowed efficient deoxygenative aromatization of oxabicyclic dienes. The reaction proceeded under neutral conditions and was compatible with various functional groups. Combining this deoxygenation with regioselective bromination and trapping of the generated aryne with furan resulted in benzannulative π-extension at the periphery of the PAHs. This enabled direct use of unfunctionalized PAHs for extension of π-conjugation. Iteration of the transformations increased the number of fused-benzene rings one at a time, which has the potential to alter the properties of PAHs by fine-tuning the degree of π-conjugation, shape, and edge topology.
- Murai, Masahito,Ogita, Takuya,Takai, Kazuhiko
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supporting information
p. 2332 - 2335
(2019/02/27)
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- How Boron Doping Shapes the Optoelectronic Properties of Canonical and Phenylene-Containing Oligoacenes: A Combined Experimental and Theoretical Investigation
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Optimized syntheses of 6,13-dimesityl-6,13-dihydro-6,13-diborapentacene (DBP) and a related compound (DBI) featuring two biphenylene-2,3-diyl units in place of naphthalene-2,3-diyl moieties are reported. Striking differences between the optoelectronic properties of DBP and DBI have been experimentally observed, and explained by quantum chemical calculations. DBP is a member of the oligoacene family, DBI is a linear [N]phenylene derivative. The yellow DBP shows blue photoluminescence, the deep red DBI is nonfluorescent. Both compounds give rise to two reversible redox transitions at E12 =?2.03 V, ?2.75 V (DBP) and ?1.52 V, ?2.30 V (DBI; THF, vs. FcH/FcH+). The higher electron affinity of DBI agrees with a lower calculated LUMO energy level [?0.57 eV for DBI with respect to DBP @HF//SCS-MP2/def2-TZVP] and a higher Lewis acidity of its boron centers, which is reflected in the trend of adduct formation with small Lewis bases (MeCN, F?). The thermochemistry underlying this trend, as well as the mechanism of fluorescence quenching in DBI, are revealed by state-of-the-art quantum chemical calculations. It is suggested that the nonradiative deactivation occurs via a low-lying, doubly excited state.
- Kirschner, Sven,Mewes, Jan-Michael,Bolte, Michael,Lerner, Hans-Wolfram,Dreuw, Andreas,Wagner, Matthias
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supporting information
p. 5104 - 5116
(2017/04/18)
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- Access to polysubstituted naphthalenes and anthracenes via a retro-Diels–Alder reaction
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Naphthalene and anthracene nuclei are present in several natural and synthetic compounds. Due to their unique physical and chemical properties, access to functionalized naphthalenes and anthracenes has attracted the attention of both synthetic and medicinal chemists over the decades. In this study, successive Diels–Alder/retro-Diels–Alder reactions of dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate with various bicyclic alkenes in one pot to yield naphthalene and anthracene derivatives are reported. Using anti- and syn-cyclotrimers derived from the cyclotrimerization of benzobarrelene as alkene partner enabled efficient synthesis of trinaphthylene.
- Akin, Esra Turan,Erdogan, Musa,Dastan, Arif,Saracoglu, Nurullah
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p. 5537 - 5546
(2017/08/22)
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- MULTICYCLIC AROMATIC COMPOUND AND ORGANIC LIGHT EMITTING DEVICE USING THE SAME
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The present specification describes a multicyclic aromatic ring compound having a novel structure and an organic light emitting device using the same.
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Paragraph 0155; 0158-0159
(2017/04/21)
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- Direct Transformation of Esters into Arenes with 1,5-Bifunctional Organomagnesium Reagents
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A direct transformation of carboxylic acid esters into arenes with 1,5-bifunctional organomagnesium reagents is described. This efficient and practical method enables the one-step defunctionalization of various carboxylic acid esters to prepare benzene, anthracene, tetracene, and pentacene derivatives. A double nucleophilic addition of the 1,5-organodimagnesium reagent to the ester is followed by an immediate 1,4-elimination reaction that leads to the direct [5+1] formation of a new aromatic ring.
- Link, Achim,Fischer, Christian,Sparr, Christof
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supporting information
p. 12163 - 12166
(2015/10/12)
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- Synthesis of hydroxy, epoxy, nitrato and methoxy derivatives of tetralins and naphthalenes
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Stereoselective syntheses are described for cis,trans,cis-2,3,5-tribromo-1, 4-dihydroxytetralin, trans,trans,cis-2,3,5-tribromo-1,4-dihydroxytetralin, trans,trans,trans-1,4-dihydroxy-2,3-dibromotetralin, trans,trans,trans-1- hydroxy-2,3,4-tribromotetralin, cis,cis,cis-1,2-epoxy-3,5-dibromo-4- hydroxytetralin, anti-1,2:3,4-diepoxytetralin, 1-hydroxy-4-bromonaphthalene, trans,trans,trans-1,4-dinitrato-2,3-dibromotetralin, 1-nitrato-2,3,4- tribromotetralin, 2,3-dibromonaphthalene and 1-methoxy-4-nitrato-2,3- dibromonaphthalene. These isomeric arene oxides and disubstituted naphthalenes provide excellent precursors for a number of 1,4- and 2,3-disubstituted naphthalene derivatives that are difficult to prepare using other routes. The structures of the naphthalene and tetralin derivatives were assigned by NMR and other techniques.
- Erenler, Ramazan,Demirtas, Ibrahim,Buyukkidan, Bulent,Cakmak, Osman
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p. 753 - 757
(2007/10/03)
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- The metalation of 1- and 2-(trifluoromethyl)naphthalenes: Noteworthy site selectivities
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This article provides insight into the various factors by which electronegative substituents affect the kinetic acidity of arenes and, more specifically, naphthalenes. Both 1- and 2-(trifluoromethyl)naphthalenes were consecutively treated with an organometallic or lithium dialkylamide-type base and carbon dioxide. Due to single electron-transfer triggered side reactions, the yields of (trifluoromethyl)naphthoic acids were moderate to poor. 1-(Trifluoromethyl)naphthalene was exclusively attacked at the 2-position as expected. The 2-isomer reacted with tert-butyllithium in the presence of potassium tert-butoxide solely at the 1-position, but with sec-butyllithium in the presence of N,N,N′,N′-tetramethylethylene-diamine concomitantly at the 3- and 4-positions. Authentic samples of the key acids 1, 4, 5 and 6 were prepared based on independent, unambiguous methods.
- Cottet, Fabrice,Castagnetti, Eva,Schlosser, Manfred
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p. 798 - 803
(2007/10/03)
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- The Bergman reaction as a synthetic tool: Advantages and restrictions
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The Bergman cycloaromatization reaction efficiently converts easily prepared acyclic enediynes into aromatic rings. In order to prepare larger, functionalized fused aromatic systems using this reaction, a thorough understanding of how functionalization affects cycloaromatization is necessary. We present here our studies on the influence of substituents at three different functionalization sites on cycloaromatization, and how these functional groups can be tailored to prepare more complex systems.
- Bowles, Daniel M,Palmer, Grant J,Landis, Chad A,Scott, John L,Anthony, John E
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p. 3753 - 3760
(2007/10/03)
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- A reiterative approach to 2,3-disubstituted naphthalenes and anthracenes
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(formula presented) Simple bis(bromoethynyl)arenediynes are easily prepared by the desilylative halogenation of the corresponding trimethylsilyl derivatives. Cycloaromatization of these halogenated enediynes leads to the otherwise difficult to prepare 2,3-dibromoarenes in good yield. Alkynylation of the resulting haloaromatic compound regenerates the soluble enediyne system, homologated by one aromatic ring. This iterative methodology can be terminated by the cycloaromatization of the unsubstituted enediyne, providing the simple acene hydrocarbon.
- Bowles, Daniel M.,Anthony, John E.
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- IPTYCENES EXTENDED TRIPTYCENES
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Triptycene is the first member of a large scale of compounds for which we have coined the general term "iptycenes".The prefix (tri, pent, etc.) indicates the number of separated arene planes.By fusing from one to six 9,10-anthradiyl moieties on the triptycene framework, one can derive a first generation of iptycenes (Table 1).Of these, only 3, 4, 8 and a substituted 2 are known; the remainder provide a synthetic challenge.Potentially interesting practical and theorethical properties of iptycenes and particular structural features of several (i.e. 15, 16 and 24) arebriefly discussed, as are certain extensions beyond the compounds in Table 1.Methods for preparing useful synthons 35-41 are described.Three new, much improved syntheses of triptycene 29, itself a useful iptycene synthon, are presented.In addition, improved syntheses of pentiptycenes 3 and 33 are described, as well as the first syntheses of pentiptycenes 32, 34 and 52 and heptiptycene 54.The way is paved for future development of this mini-domain of unnatural products.
- Hart, Harold,Bashir-Hashemi, Abdollah,Luo, Jihmei,Meador, Mary Ann
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p. 1641 - 1654
(2007/10/02)
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- A Convenient Generation of 2,3-Naphthalyne. Linear Annulation of Naphthalene and a New Naphthacene Synthesis
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2,3-Naphthalyne (3) is conveniently generated by treating 2,3-dibromonaphthalene (9) with phenyllithium and is used in a two-step sequence to prepare naphthacene (1) and 1,2,3,4-tetrafluoronaphthacene (17).Thus, the cycloadditions of 3 with 2-methylisoindole (13) and 2-methyl-4,5,6,7-tetrafluoroisoindole (14) afford the naphthacenimines 15 and 16, respectively.Deamination with m-chloroperbenzoic acid (for 15) and dichlorocarbene (for 16) affords 1 and 17 in 44percent and 63percent overall yield from 9, respectively.Similarly, cycloadditions of 3 with furan and N-tert-butylpyrrole give anthracene, after extrusion of the heteroatom bridge.
- LeHoullier, Craig S.,Gribble, Gordon W.
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p. 2364 - 2366
(2007/10/02)
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- Process for the preparation of bromoarylacetylene and aryldiacetylene precursors
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Bromoarylacetylenes such as m-bromophenylacetylene and certain precursors to such bromoarylacetylene are prepared by reacting an aryldibromide with a substituted terminal acetylene compound containing at least three carbon atoms and a hydroxy group on the carbon atom adjacent to the acetylene group in the presence of a dialkyl or trialkyl amine solvent and a catalyst system consisting of a palladium complex containing two halogen moieties and two tri-substituted phosphine moieties. Additional triphenylphosphine can be added. A cuprous iodide promoter is also employed in the reaction sequence. The bromoarylacetylenes can be reacted with a substituted terminal acetylene compound as defined using the same catalyst system as defined to produce the corresponding aryldihydroxy substituted acetylenes. Certain bromophenylhydroxy substituted acetylenes are claimed as new compositions.
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