Online ISSN : 2186-2451
Print ISSN : 1344-3542
ISSN-L : 1344-3542
Volume 81 , Issue 5
Showing 1-28 articles out of 28 articles from the selected issue
Organic Electrochemistry en route for a Greener Innovation
  • Daichi KAJIYAMA, Tsuyoshi SAITOH, Shigeru NISHIYAMA
    2013 Volume 81 Issue 5 Pages 319-324
    Published: May 05, 2013
    Released: May 05, 2013
    Hypervalent iodine oxidants have been widely applied in organic reactions due to their low toxicity, ready availability, and ease of handling. We produced an oxidant, [phenyliodine(III)bis(trifluoroethoxide)] (PIFE) by anodic oxidation of iodobenzene, which possesses comparable or superior properties to those of commercially available congeners, such as [phenyliodine(III)bis(trifluoroacetate)] (PIFA) and [phenyliodine(III)diacetate] (PIDA). The availability of PIFE was demonstrated by construction of several nitrogen-containing molecular skeletons; construction of quinolinone derivatives by PIFE occurred smoothly in moderate yield. In addition, the carbazole derivatives were synthesized in higher yields than with use of PIFA. Application of this methodology enabled synthesis of the bioactive tetrahydropyrroloiminoquinone-, carbazole-, and pyrroloindole-class natural products, including makaluvamines, damirones, glycozoline, debromofrustraminol B, and CPC-1.
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  • Toru UEMUKAI, Tomoya HIOKI, Manabu ISHIFUNE
    2013 Volume 81 Issue 5 Pages 383-387
    Published: May 05, 2013
    Released: May 05, 2013
    Thermoresponsive polymers having 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) moieties were fixed on the graphite surface by using the reversible addition-fragmentation chain transfer (RAFT) graft polymerization technique. The surface of graphite has been anodically oxidized by using our original electrochemical method, and then modified with 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoyloxy groups (RAFT reagents) by esterification with the corresponding acid chlorides. From the resulting RAFT reagent-modified graphite, 2,2,6,6-tetramethyl-4-piperidyl methacrylate (TEMPMA) and N-isopropylacrylamide (NIPAAm) monomers were copolymerized stepwise under RAFT polymerization conditions to afford the thermoresponsive block-copolymer-grafted graphite, poly(TEMPMA)-block-PNIPAAm-grafted graphite. N-Oxylation of tetramethylpiperidyl groups on the resulting graphite successfully afforded the corresponding TEMPO-containing thermoresponsive polymer-grafted graphite. Redox behavior of the resulting graphites was observed by cyclic voltammetry. The potential and intensity of the cathodic current peaks were discontinuously changed below and above the lower critical solution temperature (LCST) of the grafted thermoresponsive polymers. These results indicate that the phase transition of the thermoresponsive polymer on the graphite influences the electron transfer between the TEMPO moieties and the graphite surface.
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  • Hiroki NISHIYAMA, Ikuyoshi TOMITA
    2013 Volume 81 Issue 5 Pages 388-393
    Published: May 05, 2013
    Released: May 05, 2013
    A π-conjugated polymer having 1,4-bismercapto-substituted 1,3-diene units in the main chain, prepared by the reaction of a polymer possessing titanacyclopentadiene-2,5-diyls units with benzenesulfenyl chloride (PhSCl), was subjected to the oxidation with m-chloroperoxybenzoic acid (mCPBA) to control optoelectronic properties of the resulting materials. That is, polymers possessing sulfoxide- and/or sulfone-substituted 1,3-diene units were obtained by the oxidation reactions of the polymer having phenylmercapto moieties with varied amount of mCPBA. Electrochemical properties of the resulting sulfoxide- and/or sulfone-containing polymers were studied by their cyclic voltammetric analyses, from which their HOMO and LUMO energy levels proved to be tunable by the oxidation states of the sulfur atoms (HOMO = −5.1–−5.7 eV and LUMO = −2.7–−3.1 eV).
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  • Hirofumi MAEKAWA, Tatsuya NAKAMURA, Atsushi YAMAGUCHI
    2013 Volume 81 Issue 5 Pages 394-398
    Published: May 05, 2013
    Released: May 05, 2013
    The electrochemical oxidation of ortho- and meta-anisylsilanes in the presence of sodium cyanide facilitated the direct cyanation of the aromatic ring through the exchange of a hydrogen atom and a cyano group to give cyanoanisylsilanes without elimination of the silyl group. The anodic cyanation of anisylsilanes in methanol and electrophilic reactions of the obtained cyanoanisylsilanes largely depended on the substituted position of the silyl group on the aromatic ring and on the bulkiness of the alkyl group on the silicon atom.
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