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猪股, 勝彦 ; 宇梶, 裕 ; Inomata, Katsuhiko ; Ukaji, Yutaka
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金沢大学大学院自然科学研究科物質創成<br />金沢大学理学部
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Inomata, Katsuhiko ; Noack, Steffi ; Hammam, Mostafa A. S. ; Khawn, Htoi ; Kinoshita, Hideki
概要:
金沢大学大学院自然科学研究科物質創成<br />金沢大学理学部<br />Phytochromes are photoreceptors with a bilin chromophore in which light triggers th
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e conversion between the red-absorbing form Pr and the far-red-absorbing form Pfr. Agrobacterium tumefaciens has two phytochromes, Agp1 and Agp2, with antagonistic properties: in darkness, Agp1 converts slowly from Pfr to Pr, whereas Agp2 converts slowly from Pr to Pfr. In a previous study, we have assembled Agp1 with synthetic locked chromophores 15Za, 15Zs, 15Ea, and 15Es in which the C15=C16 double bond is fixed in either the E or Z configuration and the C14-C15 single bond is fixed in either the syn (s) or anti (a) conformation. In the present study, the locked chromophores 5Za and 5Zs were used for assembly with Agp1; in these chromophores, the C4=C5 double bond is fixed in the Z configuration, and the C5-C6 single bond is fixed in either the syn or anti conformation. All locked chromophores were also assembled with Agp2. The data showed that in both phytochromes the Pr chromophore adopts a C4=C5 Z C5-C6 syn C15=C16 Z C14-C15 anti stereochemistry and that in the Pfr chromophore the C15=C16 double bond has isomerized to the E configuration, whereas the C14-C15 single bond remains in the anti conformation. Photoconversion shifted the absorption maxima of the 5Zs adducts to shorter wavelengths, whereas the 5Za adducts were shifted to longer wavelengths. Thus, the C5-C6 single bond of the Pfr chromophore is rather in an anti conformation, supporting the previous suggestion that during photoconversion of phytochromes, a rotation around the ring A-B connecting single bond occurs. © 2006 by The American Society for Biochemistry and Molecular Biology, Inc.
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| 3.
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Sakai, Hiroki ; Ding, Xia ; Yoshida, Tetsusuke ; Fujinami, Shuhei ; Ukaji, Yutaka ; Inomata, Katsuhiko
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金沢大学金沢大学理工研究域物質化学系<br />The regio- and enantioselective hetero Diels-Alder reaction of a nitroso compound with a cyclic
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dienol, cyclohexa-1,3-dienylmethanol, has been realized utilizing stoichiometric amount of tartaric acid ester as a chiral auxiliary to afford the corresponding dihydro-1,2-oxazine with complete regioselectivity and high enantioselectivity of up to 92% ee. A catalytic version of the asymmetric hetero Diels-Alder reaction of nitroso compounds with the dienol was also achieved to afford the corresponding optically active cycloadducts with up to 83% ee. The addition of MS 4A was crucial to realize reproducible high enantioselectivity. © 2008 The Japan Institute of Heterocyclic Chemistry All rights reserved.
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Wei, Weilin ; Hamamoto, Yoshihira ; Ukaji, Yutaka ; Inomata, Katsuhiko
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金沢大学大学院自然科学研究科物質創成<br />Asymmetric addition of diphenylzinc to C-alkynyl nitrones was achieved by utilizing di(t-butyl)
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(R,R)-tartrate as a chiral auxiliary to afford the corresponding optically active (S)-N-(1-phenyl-3-substituted prop-2-ynyl)hydroxylamines. By the addition of a product-like additive, enantiomeric enhancement was observed. A mixed zinc reagent, PhZnMe, improved the enantioselection to afford hydroxylamines in up to 92% ee. © 2008 Elsevier Ltd. All rights reserved.
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Serizawa, Masakazu ; Fujinami, Shuhei ; Ukaji, Yutaka ; Inomata, Katsuhiko
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金沢大学理工研究域物質化学系<br />The asymmetric addition of alkynylzinc reagents, prepared in situ from dimethylzinc and 1-alkynes, t
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o α-dinitrones derived from glyoxal and N-(4-isopropylbenzyl)hydroxylamine was investigated by utilizing dicyclohexyl (R,R)-tartrate as a chiral auxiliary. The addition reaction of methyl(2-phenylethynyl)zinc afforded the corresponding optically active C2-symmetric (R,R)-bis(hydroxylamine) derivative with enantioselectivities of 90% and 81% ee by utilizing a stoichiometric and catalytic amount of the tartrate, respectively. Furthermore, the catalytic addition reaction of several alkynylzinc reagents also furnished the corresponding bis(hydroxylamine) with moderate to good enantioselectivities. © 2008 Elsevier Ltd. All rights reserved.
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| 6.
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猪股, 勝彦 ; Inomata, Katsuhiko
概要:
金沢大学大学院自然科学研究科物質創成<br />金沢大学理学部
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Inomata, Katsuhiko
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We studied on the syntheses of linear tetrapyrrole (bilin) chromophores including the sterically locked derivatives towa
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rd the investigation of structure and function of phytochromes as photoreceptors. The synthesized chromophores were successfully assembled with bacterial and plant apophytochromes in vitro and/or in vivo to demonstrate that they are valuable tools for studies on phytochromes. © 2012 The Japan Institute of Heterocyclic Chemistry.
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| 8.
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Yoshida, Mari ; Sassa, Naotaro ; Kato, Tomomitsu ; Fujinami, Shuhei ; Soeta, Takahiro ; Inomata, Katsuhiko ; Ukaji, Yutaka
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Desymmetrization of the divinyl carbinol 1,4-pentadien-3-ol was accomplished by the asymmetric 1,3-dipolar cycloaddition
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of azomethine imines based on a magnesium-mediated, multinucleating chiral reaction system utilizing diisopropyl (R,R)-tartrate as the chiral auxiliary. The corresponding optically active trans-pyrazolidines, each with three contiguous stereogenic centers, were obtained with excellent regio-, diastereo-, and enantioselectivity, with results as high as 99%ee. This reaction was shown to be applicable to both aryl- and alkyl-substituted azomethine imines. The use of a catalytic amount of diisopropyl (R,R)-tartrate was also effective when accompanied by the addition of MgBr2. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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| 9.
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Jayasundera, Krishanthi Padmarani ; Kinoshita, Hideki ; Inomata, Katsuhiko
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Total syntheses of phycocyanobilin and its derivative bearing a photoreactive group at the D-ring were accomplished by developing a new and efficient method for the construction of A,B-rings component, which consists of the Wittig-type
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new coupling reaction of 4-(1-methoxyethyl or 1-tosylethyl)-3-methyl-5-tosyl-1,5-dihydro-2H-pyrrol-2-one and a 2-formyl pyrrole derivative in the presence of nBu3P and a base, followed by reduction with aluminum amalgam and a subsequent acid or base treatment.
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| 10.
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Takahashi, Kana ; Iwamoto, Ryoji ; Sakata, Ryo ; Soeta, Takahiro ; Inomata, Katsuhiko ; Ukaji, Yutaka
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Oxidation of 4-methylpyrrole-2-carboxylates with DDQ in the presence of a glycol proceeded smoothly on the methyl group
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at the C4 position regioselectively to afford the corresponding pyrrole-2,4-dicarboxylates directly. Direct oxidation of a methyl group of 2,4,6-trimethylphenol and 3-methyl-9H-carbazole into carboxylates was also demonstrated. © 2012 The Japan Institute of Heterocyclic Chemistry.
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