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1.
Furuta Etsuko Akiyama Kazuhiko Inoue Hiroyoshi Kataoka Yasuhide Sensui Masaaki 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(1):109-122
Journal of Radioanalytical and Nuclear Chemistry - A new dipping method was studied for the measurement of radioactive solution using plastic scintillator sheets and pellets (PSs) and a liquid... 相似文献
2.
Prof. Dr. Hiroyoshi Takamura Takayuki Fujiwara Yohei Kawakubo Prof. Dr. Isao Kadota Prof. Dr. Daisuke Uemura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):1979-1983
Stereoselective and streamlined synthesis of the proposed C79–C104 fragment 2 of symbiodinolide ( 1 ), a polyol marine natural product with a molecular weight of 2860, was achieved. In the synthetic route, the proposed C79–C104 fragment 2 was synthesized by utilizing a Julia–Kocienski olefination and subsequent Sharpless asymmetric dihydroxylation as key transformations in a convergent manner. Detailed comparison of the 13C NMR chemical shifts between the natural product and the synthetic C79–C104 fragment 2 revealed that the stereostructure at the C91–C99 carbon chain moiety of symbiodinolide ( 1 ) should be reinvestigated. 相似文献
3.
Hiroyoshi Yamaki 《代数通讯》2013,41(22):2513-2518
4.
Yutaka Maniwa Yoshinori Kumazawa Yumi Saito Hideki Tou Hiromichi Kataura Hiroyoshi Ishii 《Molecular Crystals and Liquid Crystals》2013,570(1):671-676
Abstract X-ray diffraction (XRD) and electrical resistance measurement on single-walled carbon nan-otube (SWNT) samples prepared by the arc-discharge method are reported. The XRD profile of heat-treated sample indicated that air (oxygen, and/or nitrogen and/or water) can be condensed inside the SWNTs. We also found that the electrical resistance of SWNT soot is significantly affected by exposing to the oxygen gas and humid air. 相似文献
5.
Dr. Yasunori Toda Takayuki Yoshida Kaoru Arisue Prof. Dr. Kazuaki Fukushima Dr. Hiroyoshi Esaki Ayaka Kikuchi Prof. Dr. Hiroyuki Suga 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(41):10578-10582
Chiral Lewis acid-catalyzed asymmetric alcohol addition reactions to cyclic carbonyl ylides generated from N-(α-diazocarbonyl)-2-oxazolidinones featuring a dual catalytic system are reported. Construction of a chiral quaternary heteroatom-substituted carbon center was accomplished in which the unique heterobicycles were obtained in good yields with high stereoselection. The alcohol adducts were successfully converted to optically active oxazolidine-2,4-diones by hydrolysis. Mechanistic studies by DFT calculations revealed that alcohols could be activated by Lewis acids, enabling enantioselective protonation of the carbonyl ylides. 相似文献
6.
Effects of silica nanoparticle addition on polymer semiconductor wettability and carrier mobility in solution‐processable organic transistors on hydrophobic substrates 下载免费PDF全文
Takashi Nagase Masashi Yoshikawa Saori Yamazaki Takashi Kobayashi Yoshiki Michiwaki Seiji Watase Mitsuru Watanabe Kimihiro Matsukawa Hiroyoshi Naito 《Journal of Polymer Science.Polymer Physics》2016,54(4):509-516
The effects of the addition of silica nanoparticles (SNPs) on wettability of regioregular poly(3‐hexylthiophene) (P3HT) organic semiconductor solutions on hydrophobic substrates and the carrier mobility in organic field‐effect transistors (OFETs) made of these films are investigated. The dewetting of films made from P3HT solutions on hydrophobic substrates modified with octadecyltrichlorosilane (ODTS) is markedly suppressed after the addition of SNPs with phenyl surfactants. This enables us to fabricate continuous P3HT/SNPs films with high crystallinity by the conventional spin‐coating technique, leading to higher mobility compared with P3HT FETs fabricated on non‐modified substrates. Moreover, the addition of SNPs with larger diameters compensates for the degradation of mobility associated with the increase in the concentration of SNPs. Solution‐processed P3HT/SNPs FETs on ODTS‐modified substrates exhibit a field‐effect mobility of 1.3 × 10?2 cm2 V?1 s?1, which is almost comparable to that of P3HT FETs without SNPs (2.1 × 10?2 cm2 V?1 s?1). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 509–516 相似文献
7.
Stereodivergent Synthesis and Stereochemical Reassignment of the C79–C104 Fragment of Symbiodinolide 下载免费PDF全文
Prof. Dr. Hiroyoshi Takamura Takayuki Fujiwara Yohei Kawakubo Prof. Dr. Isao Kadota Prof. Dr. Daisuke Uemura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):1984-1996
We have synthesized eight possible diastereoisomers 3 a – h of the C79–C97 fragment of symbiodinolide ( 1 ) in a stereodivergent manner by utilizing a dithiane addition to the aldehyde as a key step. Comparison of the 13C NMR chemical shifts of the natural product 1 and the synthetic products 3 a – h indicated that the relative stereostructure of this fragment in symbiodinolide ( 1 ) is that represented in 3 a or f . We have stereodivergently synthesized eight possible diastereoisomers of the C94–C104 fragment 4 a – h , and we have compared their 13C NMR chemical shifts with those of the natural product, which established the relative stereochemistry of this fragment to be that described in diastereoisomers 4 a or e . By combining the stereostructural outcomes of the C79–C97 and C94–C104 fragments, we have proposed four candidate compounds of the C79–C104 fragment 2 a – d . We also synthesized diastereoisomers 2 a and b ( 2 a in the preceding article; Chem. Eur. J. 2015 , DOI: 10.1002/chem.201503880) by a Julia–Kocienski olefination and diastereoisomers 2 c and d by a Wittig reaction. By comparing the 13C NMR chemical shifts of natural symbiodinolide ( 1 ) with those of the synthetic products 2 a – d , we have reassigned the stereostructure of the C79–C104 fragment of natural product 1 to be that depicted in diastereoisomer 2 b . 相似文献
8.
Soumen Dutta Nitee Kumari Sateesh Dubbu Sun Woo Jang Amit Kumar Hiroyoshi Ohtsu Junghoon Kim Seung Hwan Cho Masaki Kawano In Su Lee 《Angewandte Chemie (International ed. in English)》2020,59(9):3416-3422
Rational engineering and assimilation of diverse chemo‐ and biocatalytic functionalities in a single nanostructure is highly desired for efficient multistep chemical reactions but has so far remained elusive. Here, we design and synthesize multimodal catalytic nanoreactors (MCNRs) based on a mesoporous metal‐organic framework (MOF). The MCNRs consist of customizable metal nanocrystals and stably anchored enzymes in the mesopores, as well as coordinatively unsaturated cationic metal MOF nodes, all within a single nanoreactor space. The highly intimate and diverse catalytic mesoporous microenvironments and facile accessibility to the active site in the MCNR enables the cooperative and synergistic participation from different chemo‐ and biocatalytic components. This was shown by one‐pot multistep cascade reactions involving a heterogeneous catalytic nitroaldol reaction followed by a [Pd/lipase]‐catalyzed chemoenzymatic dynamic kinetic resolution to yield optically pure (>99 % ee) nitroalcohol derivatives in quantitative yields. 相似文献
9.
Hiroyoshi Takamura Yuichiro Kadonaga Chunguang Han Daisuke Uemura 《Tetrahedron》2009,65(36):7449-7725
Cross-metathesis of methyl ester which was prepared from symbiodinolide with ethylene was performed to give the C33-C42 degraded fragment. This fragment was estimated to be (36S,40S)-diol by the modified Mosher method. Stereoselective synthesis of the (36S,40S)-diol and its diastereomer (36R,40S)-diol was achieved from l-aspartic acid. Synthetic bis-(S)- and (R)-MTPA esters which were derivatized from the (36S,40S)-diol exhibited spectroscopic data identical with those of bis-(S)- and (R)-MTPA esters derived from the degraded product. Thus, the absolute stereochemistry of the C33-C42 fragment was elucidated to be (36S,40S). 相似文献
10.
Corrugated paper is produced by gluing three types of papers of the same breadth. Given a set of orders, we first assign each order to one of the standard breadths, and then sequence those assigned to each standard breadth so that they are continuously manufactured from the three rolls of the specified standard breadth equipped in the machine called corrugator. Here we are asked to achieve multi-goals of minimizing total length of roll papers, total loss of papers caused by the differences between standard breadths and real breadths of the orders, and the number of machine stops needed during production. We use integer programming to assign orders to standard breadths, and then develop a special purpose algorithm to sequence the orders assigned to each standard breadth. This is a first attempt to handle scheduling problems of the corrugator machine. 相似文献