研究者詳細 - 仁科　勇太

論文 - 仁科　勇太

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Nanocrystalline magnesium oxide-stabilized palladium(0): The Heck reaction of heteroaryl bromides in the absence of additional ligands and base 査読

Mannepalli Lakshmi Kantam, Police Vishnuvardhan Redddy, Pottabathula Srinivas, Akula Venugopal, Suresh Bhargava, Yuta Nishina

Catalysis Science and Technology 3 ( 10 ) 2550 - 2554 2013年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

An efficient and user-friendly protocol has been realized for the Heck reaction of heteroaryl bromides by using a reusable nanocrystalline magnesium oxide-stabilized palladium(0) catalyst without the aid of additional ligands and base. Dimethylamine generated under in situ conditions by the decomposition of DMF serves as the base in this reaction. The catalyst was reused with consistent activity up to four cycles. © 2013 The Royal Society of Chemistry.

DOI： 10.1039/c3cy00404j

Bromination of hydrocarbons with CBr4, initiated by light-emitting diode irradiation 査読

Yuta Nishina, Bunsho Ohtani, Kotaro Kikushima

BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY 9 1663 - 1667 2013年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：BEILSTEIN-INSTITUT

The bromination of hydrocarbons with CBr4 as a bromine source, induced by light-emitting diode (LED) irradiation, has been developed. Monobromides were synthesized with high efficiency without the need for any additives, catalysts, heating, or inert conditions. Action and absorption spectra suggest that CBr4 absorbs light to give active species for the bromination. The generation of CHBr3 was confirmed by NMR spectroscopy and GC-MS spectrometry analysis, indicating that the present bromination involves the homolytic cleavage of a C-Br bond in CBr4 followed by radical abstraction of a hydrogen atom from a hydrocarbon.

DOI： 10.3762/bjoc.9.190

Green synthesis of silver nanoparticles using aqueous rinds extract of Brucea javanica (L.) Merr at ambient temperature 査読

Salprima S. Yudha, Doni Notriawan, Eka Angasa, Totok Eka Suharto, John Hendri, Yuta Nishina

MATERIALS LETTERS 97 181 - 183 2013年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER

Aqueous rinds extract of Brucea javanica (L.) Merr has been used as the medium/reducing system for the formation of silver nanoparticles colloids. A solution of 0.01 N AgNO3 (1 ml) was added to the rind extracts (4 ml) at room temperature, and the formation of silver nanoparticles was observed using ultraviolet-visible spectrophotometer. The shape and size of the nanoparticles have been characterized using Transmission Electron Microscope (TEM) analysis. The experimental results show that the silver nanoparticles are formed easily in the extract at ambient temperature. The resulting nanoparticles were in the spherical form and the average size of the nanoparticles was about 38.00 +/- 14.00 nm. (C) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.matlet.2013.01.114

Ionic amino acids: Application as organocatalysts in the aza-Michael reaction 査読

Naoki Morimoto, Yasuo Takeuchi, Yuta Nishina

JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL 368 31 - 37 2013年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

The ethyl methyl imidazolium salts of amino acids, [emiml[AA], have been used as catalysts in the aza-Michael reaction. Furthermore, when chiral amino acids were used, a stereoselective reaction was achieved. The mechanism of the transformation was verified by the detection of a key intermediate by electrospray ionization mass spectroscopy (ESI-MS). (C) 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.molcata.2012.11.012

Copper-catalyzed oxidative aromatization of 2-cyclohexen-1-ones to phenols in the presence of catalytic hydrogen bromide under molecular oxygen 査読

Kotaro Kikushima, Yuta Nishina

RSC ADVANCES 3 ( 43 ) 20150 - 20156 2013年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Catalytic oxidative aromatization has been achieved using 2-cyclohexen-1-ones to obtain phenol derivatives in the presence of a catalytic amount of copper salt and aqueous HBr under molecular oxygen. The amount of HBr was successfully reduced to a catalytic quantity, and the other additive such as a ligand and an oxidant as well as inert conditions were unnecessary. Various mono-, di-, and trisubstituted phenols with substituents at the desired positions could be synthesized under cheap and simple conditions. An oxidative aromatization/bromination sequence was also demonstrated to obtain bromophenols with excess HBr.

DOI： 10.1039/c3ra43071e

Palladium on graphene: the in situ generation of a catalyst for the chemoselective reduction of α,ß-unsaturated carbonyl compounds 査読

Morimoto Naoki, Yamamoto Shun-ichi, Takeuchi Yasuo, Nishina Yuta

RSC ADVANCES 3 ( 36 ) 15608 - 15612 2013年

Direct bromination of hydrocarbons catalyzed by Li2MnO3 under oxygen and photo-irradiation conditions 査読

Yuta Nishina, Junya Morita, Bunsho Ohtani

RSC ADVANCES 3 ( 7 ) 2158 - 2162 2013年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

A method for the direct bromination of hydrocarbons with Br-2 using a ubiquitous and inexpensive catalyst is highly desirable. Herein, we report the selective mono-bromination of hydrocarbons in good yield using Li2MnO3 as a catalyst under irradiation with a fluorescent room light. This new catalyst can be recycled. The effect of light was investigated using action spectra, which revealed that the reaction occurred on the surface of the catalyst.

DOI： 10.1039/c2ra22197g

微生物が作るマンガン酸化物の加熱処理による結晶構造と微細構造の変化査読

木村倫康, 橋本英樹, 宮田直幸, 仁科勇太, 草野圭弘, 池田靖訓, 中西真, 藤井達生, IVO Safarik, IVO Safarik, MIRKA Safarikova, 高田潤

粉体および粉末冶金 60 ( 3 ) 92-99 (J-STAGE) - 99 2013年

記述言語：日本語出版者・発行元：Japan Society of Powder and Powder Metallurgy

In the natural aquatic environment, there are various types of biogenic manganese oxide (BMO) precipitates which are produced by manganese oxidizing microorganisms, at ambient temperature, atmosphere and neutral pH.BMO is a very interesting and useful functional material because of its unique property; hollow globule shape formed by nanosheets, large surface area and photocatalytic characteristics. In this study, thermally-processed BMO at 100 − 1000 °C was analyzed by XRD, XANES, SEM, TEM and nitrogen adsorption method to reveal the effects of heat-treatment on its crystal structure, Mn valence state, globule morphology, microstructure, pore size distribution and specific surface area. In the result, morphology of BMO is maintained below 800 °C, while nanosheets composing BMO were changed into nanoparticles at 600 °C. The crystal structure was transformed from birnessite into hausmannite (Mn₃O₄) at 600 °C. The specific surface area was increased by heat-treatment between 300 and 500 °C. In cases of artificial manganese oxides, such changes of crystal structure and specific surface area were not observed, and combustion of organic materials produced by microorganisms in BMO probably has a large effect on them.

DOI： 10.2497/jjspm.60.92

10′-Chloro-3′,4′-dihydro-2′H-spiro[cyclopropane-1,7'(6'H)-pyrimido[2,1- a]isoquinolin]-6′-one 査読

68 ( 11 ) o3252 - + 2012年11月

3-(2-Oxo-2,3,4,5-tetrahydrofuran-3-yl)-1-benzofuran-2-carbonitrile 査読

Kensuke Okuda, Takashi Hirota, Yuta Nishina, Hiroyuki Ishida

Acta Crystallographica Section E: Structure Reports Online 68 ( 9 ) o2819 - + 2012年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：INT UNION CRYSTALLOGRAPHY

The asymmetric unit of the title compound, C13H 9NO3, consists of two crystallographically independent molecules. In each molecule, the tetra-hydro-furan (THF) ring adopts an envelope conformation with one of the methyl-ene C atoms positioned at the flap. The dihedral angles between the mean plane of the THF and the benzofuran ring system are 70.85 (5) and 89.59 (6)°. In the crystal, molecules are stacked in a column along the a-axis direction through C - H⋯O hydrogen bonds, with columns further linked by C - H⋯N and C - H⋯O interactions.

DOI： 10.1107/S1600536812036835

Novel Plant Immune-Priming Compounds Identified via High-Throughput Chemical Screening Target Salicylic Acid Glucosyltransferases in Arabidopsis 査読

Yoshiteru Noutoshi, Masateru Okazaki, Tatsuya Kida, Yuta Nishina, Yoshihiko Morishita, Takumi Ogawa, Hideyuki Suzuki, Daisuke Shibata, Yusuke Jikumaru, Atsushi Hanada, Yuji Kamiya, Ken Shirasu

PLANT CELL 24 ( 9 ) 3795 - 3804 2012年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER SOC PLANT BIOLOGISTS

Plant activators are compounds, such as analogs of the defense hormone salicylic acid (SA), that protect plants from pathogens by activating the plant immune system. Although some plant activators have been widely used in agriculture, the molecular mechanisms of immune induction are largely unknown. Using a newly established high-throughput screening procedure that screens for compounds that specifically potentiate pathogen-activated cell death in Arabidopsis thaliana cultured suspension cells, we identified five compounds that prime the immune response. These compounds enhanced disease resistance against pathogenic Pseudomonas bacteria in Arabidopsis plants. Pretreatments increased the accumulation of endogenous SA, but reduced its metabolite, SA-O-beta-D-glucoside. Inducing compounds inhibited two SA glucosyltransferases (SAGTs) in vitro. Double knockout plants that lack both SAGTs consistently exhibited enhanced disease resistance. Our results demonstrate that manipulation of the active free SA pool via SA-inactivating enzymes can be a useful strategy for fortifying plant disease resistance and may identify useful crop protectants.

DOI： 10.1105/tpc.112.098343

Characterization of hybrid composite membrane based polymer/precursor/SiO2 査読

Uma Thanganathan, Yuta Nishina, Kunio Kimura, Satoshi Hayakawa, Rambabu Bobba

MATERIALS LETTERS 81 88 - 91 2012年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

New class of hybrid composite was synthesized via sol-gel process with the combination of poly(vinyl alcohol) (PVA), TEOS, 3-glycidyloxypropyltrimethoxysilane (GPTMS) reacted with the cross-linking agent glutaraldehyde. The composites demonstrated a maximum high proton conductivity of 1.7 x 10(-2) S cm(-1) at 140 degrees C and a relative humidity of 50% RH. The swelling ratio was calculated in dry and wet conditions, and the composites were found capable of swelling. The structural formation of the composites was studied by techniques such as FTIR, TGA and impedance spectroscopy, and it was concluded that these PVA-SiO2/GPTMS/GA composite membranes exhibited excellent thermal, mechanical and conductivity properties. (C) 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.matlet.2012.04.023

Hydrothiolation and Intramolecular Cyclization Sequence for the Synthesis of 1,3-Oxathiine Frameworks 査読

Yuta Nishina, Junya Miyata

SYNTHESIS-STUTTGART 44 ( 16 ) 2607 - 2613 2012年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：GEORG THIEME VERLAG KG

1,3-Oxathiine frameworks can be prepared via the sequential addition and intramolecular cyclization of thiosalicylic acid onto alkynes. A substituent on the alkyne and the presence of a palladium catalyst can allow product regioselectivity control. This strategy is applicable to the synthesis of heterocycles comprising sulfur and oxygen atoms, namely 3,1-benzoxathiines, without any unwanted byproduct.

DOI： 10.1055/s-0032-1316563

Ruthenium/magnesium-lanthanum mixed oxide: An efficient reusable catalyst for oxidation of alcohols by using molecular oxygen 査読

M. Lakshmi Kantam, R. Sudarshan Reddy, Ujjwal Pal, M. Sudhakar, A. Venugopal, K. Jeeva Ratnam, F. Figueras, Venkat Reddy Chintareddy, Yuta Nishina

JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL 359 1 - 7 2012年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

An efficient method for the oxidation of benzylic and secondary aromatic alcohols into their corresponding aldehydes or ketones has been achieved by using ruthenium supported magnesium lanthanum mixed oxide as a heterogeneous catalyst in toluene, with molecular oxygen as the sole oxidant. This catalyst can also be operated in solvent free conditions at 393 K and reused for five cycles with consistent yield and selectivity. (C)2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.molcata.2012.03.013

Catalytic guanylation of aliphatic, aromatic, heterocyclic primary and secondary amines using nanocrystalline zinc(II) oxide 査読

M. Lakshmi Kantam, S. Priyadarshini, P. J. Amal Joseph, P. Srinivas, A. Vinu, K. J. Klabunde, Yuta Nishina

TETRAHEDRON 68 ( 29 ) 5730 - 5737 2012年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Nanocrystalline ZnO was found to be a highly efficient heterogeneous catalyst for the guanylation of amines with various carbodiimides to afford N,N',N ''-trisubstituted guanidines in excellent yields. Structurally divergent aliphatic, aromatic, heterocyclic primary and secondary amines were converted to the corresponding N,N',N ''-trisubstituted guanidines using optimal conditions. The catalyst was easy to handle even under atmospheric conditions and can be easily recovered by centrifugation and reused for five cycles with consistent activity. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2012.05.044

Arrangement and Dispersion of Rh and Pt Atoms on Graphene Oxide Sheets 査読

Kazuma Gotoh, Hideki Hashimoto, Ryo Kawai, Yuta Nishina, Eiji Fujii, Takahiro Ohkubo, Atsushi Itadani, Yasushige Kuroda, Hiroyuki Ishida

CHEMISTRY LETTERS 41 ( 7 ) 680 - 682 2012年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

Hybrid materials of ultimately minimized metal particles, namely, isolated atoms or subnano-sized particles, on thermally exfoliated graphene oxide sheets were produced using cation-exchanged highly oxidized graphite as a precursor. Rh atoms on graphene sheets arrange with a regular spacing of 0.50 or 0.45 nm and form square or rectangular grid patterns, whereas isolated Pt atoms disperse on graphene sheets randomly.

DOI： 10.1246/cl.2012.680

酸化薄片化黒鉛及びその製造方法査読

仁科勇太

特願2012-083453，岡山大学 2012年

Recyclable Pd-graphene catalyst: mechanistic insights into heterogeneous and homogeneous catalysis 査読

Yuta Nishina, Junya Miyata, Ryo Kawai, Kazuma Gotoh

RSC ADVANCES 2 ( 25 ) 9380 - 9382 2012年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Pd-graphene, a composite of Pd nanoparticles and exfoliated graphene, was used as a catalyst in organic reactions. In the Suzuki-Miyaura cross-coupling reaction, Pd-graphene showed high reusability without aggregation of Pd nanoparticles. The intermediates of the reaction in the liquid phase, Ph-Pd-Br and Ph-Pd-OH, were detected by ESI-MS.

DOI： 10.1039/c2ra21185h

Bromination of aromatic compounds using an Fe2O3/zeolite catalyst 査読

Yuta Nishina, Keishi Takami

GREEN CHEMISTRY 14 ( 9 ) 2380 - 2383 2012年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

The catalytic bromination of non-activated aromatic compounds has been achieved using an Fe2O3/zeolite catalyst system. FeBr3 was identified as the catalytic species, formed in situ from HBr and Fe2O3. The catalyst was easy-to-handle and cost effective and could also be recycled. The reaction system was also amenable to the one-pot sequential bromination/C-C bond formation of benzene.

DOI： 10.1039/c2gc35821b

Biogenic manganese oxide: effective new catalyst for direct bromination of hydrocarbons 査読

Yuta Nishina, Hideki Hashimoto, Noriyasu Kimura, Naoyuki Miyata, Tatsuo Fujii, Bunsho Ohtani, Jun Takada

RSC ADVANCES 2 ( 16 ) 6420 - 6423 2012年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Nano- and micro-architectural manganese oxide produced by microorganisms catalyses the selective monobromination of hydrocarbons in excellent yield under irradiation of fluorescent room light. The knowledge gained from investigating natural materials will lead to unprecedented catalyst designing toward efficient organic reactions.

DOI： 10.1039/c2ra20896b

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