- Acetic anhydride mediated condensation of aromatic o-diacid dichlorides with benzimidazoles to provide electro-reducible p-dione adducts
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Acetic anhydride mediates a facile and rapid condensation of benzimidazole with aromatic o-diacid dichlorides to precipitate p-dione adducts in excellent yields. Condensation with pyridine-3,4-dicarbonyl dichloride produced a 1:1 mixture of isomeric p-diones. The X-ray crystal structure of one of the latter isomers revealed unusual high density, and inter-layer separation similar to graphite. Cyclic voltammetry demonstrated that p-dione is capable of two consecutive one-electron-reductions with formal potentials influenced by the fused (hetero)aromatic and substituent effects.
- Joyce, Eamonn,Kavanagh, Paul,Leech, Dónal,Karpinska, Jolanta,McArdle, Patrick,Aldabbagh, Fawaz
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- Synthesis of 1,3,4-oxadiazoles as selective T-type calcium channel inhibitors
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– Neuropathic pain, epilepsy, insomnia, and tremor disorder may arrive from an increase of intracellular Ca2+ concentration through a dysfunction of T-type Ca2+ channels. Thus, T-type calcium channels could be a target in drug discovery for the treatments of neuropathic pain and epilepsy. From rational drug design approach, a group of 2,5-disubstituted 1,3,4-oxadiazole molecules was synthesized and their selective T-type channel inhibitions were evaluated. The synthetic strategy consists of a short sequence of three reactions: (i) condensation of thiosemicarbazide with acid chlorides; (ii) ring closing by 1,3-dibromo-5,5-dimethylhydantoin; and (iii) coupling with various acid chlorides. 5-Chloro-N-(5-phenyl-1,3,4-oxadiazol-2-yl)thiophene-2-carboxamide (11) was found to selectively inhibit T-type Ca2+ channel over Na+ and K+ channels in mouse dorsal root ganglion neurons and/or human embryonic kidney (HEK)-293 cells and to suppress seizure-induced death in mouse model. Consequently, compound 11 is a useful probe for investigation of physiologic and pathophysiologic roles of the T-channel, and provides a basis to develop a novel therapeutic to treat chronic neuropathic and inflammatory pains.
- Zhang, Man,Zou, Bende,Gunaratna, Medha J.,Weerasekara, Sahani,Tong, Zongbo,Nguyen, Thi D.T.,Koldas, Serkan,Cao, William S.,Pascual, Conrado,Xie, Xinmin Simon,Hua, Duy H.
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p. 145 - 164
(2020/02/04)
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- Oligothiophene quinoids containing a benzo[: C] thiophene unit for the stabilization of the quinoidal electronic structure
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Bis(dicyanomethylene)-substituted quinoidal π-conjugated systems possess a high electron-accepting nature and thus have been extensively investigated for application as n-type semiconductors. We focus on the utilization of benzene-annelation for the stabilization of the quinoidal electronic structure against the biradicaloid structure by designing quinoidal thiophenes 3-mer (BTQ) and 6-mer (BTQ-6) that have benzo[c]thiophene units. We also develop quinoidal oligothiophenes (BTQ-F) consisting of both benzo[c]thiophene and fluorinated thiophene units. The influence of benzo[c]thiophene on the quinoidal electronic structure is investigated by theoretical studies and property measurements. The molecular structure of BTQ-F is unambiguously confirmed through single-crystal X-ray diffraction. Analyses of cyclic voltammetry reveal that the lowest unoccupied molecular orbital energy levels of these compounds lie below -4.0 eV, leading to good electron-transporting characteristics even under ambient conditions in organic field-effect transistors (OFETs). Due to an increased highest occupied molecular orbital energy level, ambipolar transport is observed in BTQ-6, indicating the versatility of quinoidal π-conjugated systems incorporating benzo[c]thiophene.
- Yamamoto, Keitaro,Ie, Yutaka,Nitani, Masashi,Tohnai, Norimitsu,Kakiuchi, Fumitoshi,Zhang, Ke,Pisula, Wojciech,Asadi, Kamal,Blom, Paul W. M.,Aso, Yoshio
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supporting information
p. 7493 - 7500
(2018/07/29)
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- Computational and Experimental Studies of Phthaloyl Peroxide-Mediated Hydroxylation of Arenes Yield a More Reactive Derivative, 4,5-Dichlorophthaloyl Peroxide
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The oxidation of arenes by the reagent phthaloyl peroxide provides a new method for the synthesis of phenols. A new, more reactive arene oxidizing reagent, 4,5-dichlorophthaloyl peroxide, computationally predicted and experimentally determined to possess enhanced reactivity, has expanded the scope of the reaction while maintaining a high level of tolerance for diverse functional groups. The reaction proceeds through a novel "reverse-rebound" mechanism with diradical intermediates. Mechanistic insight was achieved through isolation and characterization of minor byproducts, determination of linear free energy correlations, and computational analysis of substituent effects of arenes, each of which provided additional support for the reaction proceeding through the diradical pathway.
- Camelio, Andrew M.,Liang, Yong,Eliasen, Anders M.,Johnson, Trevor C.,Yuan, Changxia,Schuppe, Alex W.,Houk,Siegel, Dionicio
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p. 8084 - 8095
(2015/09/01)
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- Synthesis and characterization of a poly(1,3-dithienylisothianaphthene) derivative for bulk heterojunction photovoltaic cells
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The synthesis of a poly(1,3-dithienylisothianaphthene) (PDTITN) derivative obtained via oxidative polymerization of 5,6-dichloro-l,2-bis(3a?2-dodecylthienyl)isothianaphthene is described. PDTITN exhibits a band gap of 1.80-1.85 eV. The redox properties of PDTITN were characterized using cyclic voltammetry and spectroelectrochemisty. Photoexcitation of PDTITN results in photoluminescence (PL) in the near-IR region and the formation of a triplet state. In the presence of a methanofullerene (PCBM) as an electron acceptor, PL and triplet formation of PDTITN are quenched. In photovoltaic devices using blends of the polymer with PCBM, the observed incident-photon-to-collected-electron efficiency (IPCE) up to 24% at 400 nm and the 3 orders of magnitude increase of short circuit current as compared to the polymer alone prove the photoactivity of the PDTITN/PCBM blend in the device.
- Vangeneugden,Vanderzande,Salbeck,Van Hal,Janssen,Hummelen,Brabec,Shaheen,Sariciftci
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p. 11106 - 11113
(2007/10/03)
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