- Preparation of isobenzofurandiones by flash vacuum pyrolysis involving retro-Diels-Alder expulsion of ethylene and concomitant C-O cleavage of methoxy or ethylenedioxy groups
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Flash vacuum pyrolysis (fvp) of a number of substrates, prepared by hydrogenating adducts derived from dimethoxy- or ethylenedioxy-substituted benzynes and furan, affords isobenzofurandiones through retro-Diels-Alder expulsion of ethylene and C-O bond cleavage of the methoxy or ethylenedioxy groups. The parent isobenzofuran-4,5-dione is reactive and undergoes two-fold conjugate addition of water to afford 3,4-dihydroxybenzene-1,2-dicarboxaldehyde.
- Slamet, Riskiono,Wege, Dieter
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- Design of twisted conjugated molecular systems towards stable multi-colored electrochromic polymers
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Promising advancement of conjugated polymers in electrochromic devices require to design high-performance electrochromic polymers with rich color conversion and long-term stability under cyclic electrical loads. Here we report a new strategy in developing multi-colored electrochromic polymers with good stability via twisted conjugated molecular engineering. A series of twisted hybrid precursors are synthesized by coupling ortho-alkylenedioxybenzenes with EDOT units, and their corresponding polymers are facilely electrosynthesized at relatively low polymerization potentials. The structure-property relationships of such ortho-alkylenedioxybenzene-EDOT hybrid precursors and polymers are systematically elucidated via DFT calculations, spectral, morphological, electrochemical and spectroelectrochemical analysis, etc. We demonstrate that the dihedral angle between ortho-alkylenedioxybenzenes and EDOT moieties can substantially affect the electrochemical and electrochromic properties of polymers. As the dihedral angle and electron cloud density increases, these hybrid polymers display distinct multiple color switching nature and good overall performance including high coloration efficiency (>200 cm2 C?1), decent optical contrast (>45percent), fast switching (1 s), and excellent switching stability (96percent of optical contrast after 3500 cycling) under cyclic electrical loads. With these findings, this work will provide novel insights for rational design of stable and highly efficient multi-colored electrochromic polymers.
- Gu, Hua,Hu, Faqi,Jian, Nannan,Lin, Kaiwen,Liu, Ximei,Lu, Baoyang,Wu, Tao,Xu, Jingkun,Xue, Yu
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- Bromination of arenes using I2O5-KBr in water
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An efficient and environmentally benign bromination of various aromatic compounds using aN aqueous I2O5-KBr system at room temperature has been developed in this work. A series of aromatic compounds such as acetophenones, benzaldehydes, benzoic acids, anilines, amides, and aminopyridine have been successfully brominated in excellent regioselectivities and good yields under the typical reaction conditions. The features of KBr as brominating reagent, water as solvent, and mild conditions make this system an attractive synthetic procedure. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Hou, Jieping,Li, Zejiang,Jia, Xiao-Dong,Liu, Zhong-Quan
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supporting information
p. 181 - 187
(2013/12/04)
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- Auto-tandem catalysis: Synthesis of acridines by Pd-catalyzed C=C bond formation and C(sp2)-N cross-coupling
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A facile palladium-catalyzed synthesis of acridines has been realized by consecutive C=C double bond formation and C-N cross-coupling. A variety of functionalized acridines can be accessed from easily available o-dihalobenzenes and N-tosylhydrazones in a single operation. This one-pot protocol has a wide scope with respect to both coupling partners, and provides an efficient route to functionalized acridine derivatives, which are generally difficult to synthesize by previously known methods.
- Huang, Zhongxing,Yang, Yang,Xiao, Qing,Zhang, Yan,Wang, Jianbo
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supporting information
p. 6586 - 6593
(2013/01/15)
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- Synthesis of annulated dioxins as electron-rich donors for cation radical salts
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The synthesis of a series of new alkoxylated linearly annulated dioxins is described together with their cyclic voltammetric behavior and some preliminary result on their ability to form cation radical salts. Of these dioxins, seven (8, 12, 19, 21, 27, 33, 34) are the first representatives of entirely new heterocyclic systems. Dioxins 8, 21, 22 and 27 gave good quality cation radical salts upon electrocrystallization. Graphical Abstract
- Hellberg, Jonas,Dahlstedt, Emma,Pelcman, Margit E.
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p. 8899 - 8912
(2007/10/03)
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- Process development of the synthetic route to sulamserod hydrochloride
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Sulamserod hydrochloride is a potent S-HT4 receptor antagonist and was a clinical candidate for the treatment of gastrointestinal disorders. Process development of the fairly long synthetic route (12 linear, 14 overall steps) was undertaken. Process improvements were highlighted by aromatic chlorination choices in making dichlorobenzodioxan 2 and acetylaminochloroketone 7, a transfer hydrogenation reducing a nitro group and simultaneous aromatic dechlorination without ketone reduction to give aminoketone 5, and use of the potential mutagenic iodosulfonamide 14 to make quaternary salt 11. The chemistry was scaled-up into pilot plant reactor vessels to produce multikilogram amounts of Sulamserod hydrochloride suitable for drug development.
- Kowalczyk, Bruce A.,Robinson III, James,Gardner, John O.
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p. 116 - 121
(2013/09/07)
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