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Chūō-ku, Japan

Fukushima H.,Waseda University | Mori H.,Waseda University | Arime M.,Waseda University | Iwatsuki S.,Konan University | And 2 more authors.
European Journal of Inorganic Chemistry | Year: 2011

Reactions of head-to-head (HH) α-pyridonato- and pivalamidato-bridged platinum(III) binuclear complexes withacetone were investigated kinetically. The reactions with acetone proceeded slowly to form acetonyl PtIII binuclear complexes in two steps. A mechanism, which involves π-coordination of the enol form of acetone in the first step, followed by the π-β bond conversion in the second step, is proposed. π-Coordination of the enol was strongly supported by kinetic analyses of a ligand substitution reaction involving the pivalamidato-bridged PtIII binuclear complex with (4-hydroxyphenyl)pyruvic acid. Only the enol form was reactive towards the PtIII dimer complex. The enol form of acetone coordinates to the Pt(N2O2) atom in the HH amidato-bridged platinum(III) binuclear complex atfirst, and then the π-coordinated acetone changes to the β-coordinated acetone to form the acetonyl PtIII binuclear complex. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Uemura K.,Gifu University | Fukui K.,Waseda University | Yamasaki K.,Waseda University | Matsumoto K.,Waseda University | And 2 more authors.
Inorganic Chemistry | Year: 2010

The quasi-one-dimensional chain [{PtRh(TCM)2(NH 3)2Cl2.5}2{Pt2(PVM) 2(NH3)4}2]n(PF 6)6n·2nH2O (Chain-2; TCM = Cl 3CCONH-, PVM = tBuCONH-), which consists of Pt and Rh atoms, has been obtained from two dinuclear compounds, [Pt2(PVM)2(NH3)4](PF 6)2·H2O (1) and [PtRh(TCM) 2(NH3)2Cl3] (2). Single-crystal X-ray analysis showed that the dinuclear compounds stack with metal-metal bonds to form octameric units, Pt-Rh-Pt-Pt-Pt-Pt-Rh-Pt (Pt6Rh2), that are bridged by the Cl- ion to be a quasi-one-dimensional chain. Elemental analysis, X-ray photoelectron spectroscopy, electron paramagnetic resonance (EPR), and magnetic susceptibility measurements showed that Chain-2 has a mixed valency and one unpaired electron per octameric Pt 6Rh2 unit. Taking into account the small observed g av value (gav = 2.01 at room temperature) obtained by EPR measurement and B3LYP density functional theory calculations of the model complex, oxidation states of the octameric unit are postulated to be Pt 3+-Rh2.5+-Pt2+-Pt2+-Pt 2+-Pt2+-Rh2.5+-Pt3+, where the EPR isotropic signal showed that the unpaired electron resides in the Rh d xy orbitals (Δ* orbitals in Pt-Rh dinuclear parts) and hops from one Rh atom to another. © 2010 American Chemical Society. Source

Kimura H.,Juntendo University | Kon N.,Juntendo University | Furukawa S.,Toyo University | Mukaida M.,National Defense Medical College | And 4 more authors.
Clinical and Experimental Hypertension | Year: 2010

The purpose of this study is to elucidate the effect of wheel training on oxidative stress maker levels in spontaneous hypertensive rats (SHR). 4-hydroxynonenal and 3-nitrotyrosine levels in the aorta of SHRs were allowed to run for 10 weeks from the age of 15 weeks were measured and compared with those of nonexercised SHRs. The 4-hydroxynonenal and 3-nitrotyrosine levels in the exercised group were significantly lower than those in the nonexercised group. The exercised group showed a significant increase of manganese-containing superoxide dismutase. Endurance exercise showed a possible suppressing effect on the arteriosclerosis development by reducing oxidative stress, even after emergence of hypertension. © 2010 Informa UK Ltd. Source

Shiina I.,Tokyo University of Science | Nakata K.,Tokyo University of Science | Ono K.,Tokyo University of Science | Mukaiyama T.,Tokyo Chemical Industry Co.
Helvetica Chimica Acta | Year: 2012

Pyridine-3-carboxylic anhydride (3-PCA) was found to function as an efficient coupling reagent for the preparation of carboxylic esters from various carboxylic acids with alcohols under mild conditions by a simple experimental procedure. This novel condensation reagent 3-PCA was applicable not only for the synthesis of achiral carboxylic esters catalyzed by 4-(dimethylamino)pyridine (DMAP) but also for the production of chiral carboxylic esters by the combination of chiral nucleophilic catalyst, such as tetramisole (=2,3,5,6-tetrahydro-6-phenylimidazo[2,1-b][1,3]thiazole) derivatives. An efficient kinetic resolution of racemic benzylic alcohols with achiral carboxylic acids was achieved by using 3-PCA in the presence of (R)-benzotetramisole ((R)-BTM), and a variety of optically active carboxylic esters were produced with high enantiomeric excesses by this new chiral induction system without using a tertiary amine. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich, Switzerland. Source

Mukaiyama T.,Tokyo Chemical Industry Co. | Kuroda K.,Tokyo University of Science | Maruyama Y.,Tokyo University of Science
Heterocycles | Year: 2010

A new type of oxidation-reduction condensation of alcohols with sulfur, nitrogen, and oxygen nucleophiles by the combined use of phenyl diphenylphosphinite (PhOPPh2) and oxidants such as azides or diethyl azodicarboxylate (DEAD) are described. In these reactions, chiral secondary and tertiary alcohols are converted into the corresponding chiral sulfides, azides, esters and ethers under mild and neutral conditions with almost complete inversion of stereochemical configuration. © 2010 The Japan Institute of Heterocyclic Chemistry. Source

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