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121.
Tetsuro Shimo Masayuki Ohe Kenichi Somekawa Otohiko Tsuge 《Journal of heterocyclic chemistry》1991,28(8):1831-1833
3-(2H-Pyran-2-on-6-yl)indolizines 6a-d were prepared by 1,3-dipolar cycloaddition reactions of N-(2H-pyran-2-on-6-yl)methylpyridinium bromides 5a,b with dimethyl acetylenedicarboxylate (DMAD). All of the cycloaddition reactions of 6b with N-phenylmaleimide, p-benzoquinone, and DMAD took place at the 2-pyrone ring to give 3-substituted indolizines. 相似文献
122.
[reaction: see text] Total synthesis of the potent AMPA/KA receptor antagonist (-)-kaitocephalin (1) and its three diastereomers has been accomplished. The synthesis features strictly substrate-controlled operations to alpha-formylglutamate 3 starting with alpha-hydroxymethylglutamate 4. The requisite 2R,3S,7R-stereocenters were efficiently constructed by manipulation of stereoselective reactions: dihydroxylation of 7 followed by azide substitution of the corresponding thionocarbonate 10 and Cu-mediated allylation of an acyliminium ion 21. All of the protecting groups in 26 were removed simultaneously by AlCl3/Me2S to give 1. 相似文献
123.
Sekiguchi Y Mitsuhashi N Inoue Y Yagisawa H Mimura T 《Journal of chromatography. A》2004,1039(1-2):71-76
This paper describes the development of a practical method for the analysis of sugar phosphates from the model higher plant Arabidopsis thaliana by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The extraction method of sugar phosphates from higher plants was first optimized for HPAEC-PAD analysis. In order to improve the resolution in HPAEC-PAD, a column packed with titanium dioxide resin was used. The titanium dioxide column was used as a trap-column for sugar phosphates and nucleotides, for the removal of sample matrices. Sample pretreatment was achieved in-line and automatically using a six-port valve placed after the injection valve. 相似文献
124.
Tachikawa T Yoshida A Tojo S Sugimoto A Fujitsuka M Majima T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(21):5345-5353
The TiO2 photocatalytic one-electron oxidation mechanism of aromatic sulfides with a methylene bridging group (-(CH2)n-, n=0-4) between the 4-(methylthio)phenyl chromophore and the carboxylate binding group on the surface of a TiO2 powder slurried in acetonitrile (MeCN) has been investigated by time-resolved diffuse reflectance (TDR) spectroscopy. The electronic coupling element (H(DA)) between the hole donor and acceptor, which was estimated from the spectroscopic characteristics of the charge transfer (CT) complexes of the substrates (S) and the TiO2 surface, exhibited an exponential decline with the increasing of the methylene number of S. The determined decay factor (beta) of 9 nm(-1) also supports the fact that the 4-(methylthio)phenyl chromophore is separated from the TiO2 surface. The efficiency of the one-electron oxidation of S adsorbed on the TiO2 surface, which was determined from the relationship between the amount of adsorbates and the concentration of the generated radical cations, significantly depended on the H(DA) value, but not on the oxidation potential of S determined in homogeneous solution. 相似文献
125.
Tetsuro Shimo Katsuyuki Kataoka Ayumi Maeda Kenichi Somekawa 《Journal of heterocyclic chemistry》1992,29(4):811-813
Diels-Alder reactions of 2-pyrone (1) with fumaronitrile and maleonitrile afforded regio- and stereo-specific mono-adducts 3a and 3b , respectively. The reaction of 1 with acrylonitrile gave a bis-adduct. The reaction of 4,6-dimethyl-2-pyrone (7) with dimethyl fumarate and dimethyl maleate at higher temperature gave benzene derivatives. The low reactivity of 7 and the instability of the mono-adducts with 7 were considered from the existence of back reaction and easy elimination of methyl formate, respectively. Hydrolyses of the mono-adducts of 2-pyrones gave polyfunctionalized cyclohexenes and elimination products generated from the preferencial trans-elimination of the leaving groups. 相似文献
126.
127.
The baker's yeast reduction of 2-(1,3-dithian-2-yl)-3-oxobutanoates gave (2R,3S)-2-(1,3-dithian-2-yl)-3-hydroxybutanoates in good yiels and in high diastereo- and enantioselectivity. 相似文献
128.
Tetsuro Yamashita Shigeo Ohara Isao Sakamoto 《Physica C: Superconductivity and its Applications》2011,471(23-24):1655-1659
We have grown high purity single crystals of Ce2CoIn8 using the self-flux technique, and have investigated its transport, thermal, and magnetic properties, including the anisotropic features. Single crystals of Ce2CoIn8 were grown in the lower temperature region to avoid the formation of un-wanted phases such as CeCoIn5 and CeIn3 impurities. The results of the structural and physical measurements imply that the present single crystals have high purity. The electrical resistivity and specific heat measurements demonstrate that Ce2CoIn8 has a superconducting ground state with a distinct non-Fermi liquid character. This indicates that the superconductivity in Ce2CoIn8 arises out of the verge of the underlying quantum critical instability mediated by the antiferromagnetic correlations. Additionally, we investigate the crystalline electric field (CEF) energy scheme based on the temperature dependence of the specific heat and the anisotropic features in the susceptibility. We propose one of the CEF level schemes calculated on the basis of the CEF model that the first and second CEF states are located at Δ1 = 82 K and Δ2 = 102 K above the ground state doublet, respectively. 相似文献
129.
Palchunova Kseniya Mino Toshihiro Mihashi Toshifumi Liu Jonathan Tasaki Kuniharu Hasegawa Yumi Hiraoka Takahiro Oshika Tetsuro 《Optical Review》2022,29(3):188-196
Optical Review - To evaluate the repeatability of the optical coherence tomography (OCT) retinal shape measurement with and without alignment correction in children and adults. 62 eyes of the 31... 相似文献
130.