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71.
Masaki Matsui Yuya Tsuzuki Yasuhiro Kubota Kazumasa Funabiki Toshiyasu Inuzuka Kazuhiro Manseki Shinji Higashijima Hidetoshi Miura Hiroyasu Sato Tsukasa Yoshida 《Tetrahedron》2018,74(40):5867-5878
(2R,3aR,8bR)- and (2S,3aS,8bS)-2-Methyl indoline dye tetrabutylammonium carboxylates exhibited the highest conversion efficiency among four regio and stereo isomers. These indoline dyes also showed higher conversion efficiency than DN350. 相似文献
72.
Nuclear magnetic resonance studies of alkaline earth phosphosilicate and aluminoborosilicate glasses
Hiroshi Yamashita Hidetake Yoshino Keishi Nagata Hyuma Inoue Takeshi Nakajin Takashi Maekawa 《Journal of Non》2000,270(1-3):48-59
The 11B, 27Al, 29Si and 31P magic angle spinning (MAS) NMR spectra of MO–P2O5, MO–SiO2–P2O5 and MO(M′2O)–SiO2–Al2O3–B2O3 (M=Mg, Ca, Sr and Ba, M′=Na) glasses were examined. In binary MO–P2O5 (M=Ca and Mg) glasses, the distributions of the phosphate sites, P(Qn), can be expressed by a theoretical prediction that P2O5 reacts quantitatively with MO. In the ternary 0.30MO–0.05SiO2–0.65P2O5 glasses, the 6-coordinated silicon sites were detected, whose population increases in the order of MgOxCaO–0.05SiO2–(0.95−x)P2O5 glasses, its population increases with an increase in f (=([P2O5]−[MO]−[B2O3]−[Na2O])/[SiO2]) and has maximum at f=9. The signal due to the 5-coordinated silicon atoms is also observed when x is smaller than 0.45. When three network-forming oxides such as SiO2, Al2O3 and B2O3 coexist, Al2O3 reacts preferably with MO. The populations of 4-coordinated boron atoms, N4, are expressed well with r/(1−r), where r=([Na2O]−[Al2O3])/([Na2O]−[Al2O3]+[B2O3]). The correlation of the Raman signal at 1210 and 1350 cm−1 with the NMR signal of Si(Q6) at −215 ppm is also seen. 相似文献
73.
Acyloxymethyl radicals were generated from the corresponding iodomethyl esters and successfully underwent addition to the CN bond of N-Ts, N-PMP, and N-Dpp imines by the action of dimethylzinc or triethylborane. Ethyl acetate, toluene, and benzene as well as dichloromethane were suitable solvents. The utility of acyloxymethyl radicals as a hydroxymethyl anion equivalent was highlighted by the facile hydrolysis of the acyloxy moiety of the adducts to give the corresponding amino alcohol derivatives in good to high yield. 相似文献
74.
Choi JC Kohno K Masuda D Yasuda H Sakakura T 《Chemical communications (Cambridge, England)》2008,(6):777-779
Iron triflate, in situ-formed from FeCl3 and triflic acid, or FeCl3 and silver triflate efficiently catalyse the intermolecular addition of carboxylic acids to various alkenes to yield carboxylic esters; the reaction is applicable to the synthesis of unstable esters, such as acrylates. 相似文献
75.
Equilibrium conditions for clathrate hydrates formed from methane and different concentrations of 1-propanol or 2-propanol aqueous solutions were experimentally determined at temperatures of 274.0–287.1 K and pressures up to 11.0 MPa. Each propanol has an inhibiting and/or promoting effect on hydrate formation depending on the propanol concentration. A structural transition from a structure I to a different hydrate structure occurred at concentrations between 3 and 5 mass% for 1-propanol and between 2 and 3 mass% for 2-propanol. 相似文献
76.
77.
Hideki Maekawa Kotaro Kawata Yue Ping Xiong Natsuko Sakai Harumi Yokokawa 《Solid State Ionics》2009,180(4-5):314-319
Local coordination structure around Yttrium ions in CeO2–Y2O3 binary and [(CeO2)x(ZrO2)1?x]0.8(YO1.5)0.2 (x = 0.0 ~ 1.0) ternary system has been investigated by 89Y MAS-NMR. NMR spectra are found to be consisted of multiple peaks that can be assigned to 6-, 7- and 8-oxygen coordinated Yttrium ions. Compositional dependence of the spectrum was observed and compared with the previous results for ZrO2–Y2O3 binary system. The present investigation suggested the degree of localization of the oxygen vacancy around the cation is in the order of Zr4+ > Y3+ > Ce4+. The degree of the oxygen vacancy preference for each cation was quantitatively determined for CeO2–ZrO2–Y2O3 ternary system the first time. 相似文献
78.
Guo‐Qing Bian Takayoshi Kuroda‐Sowa Hisashi Konaka Masahiko Maekawa Megumu Munakata 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(7):m338-m340
The title compound, [Mn2(μ‐O)(C6H3NO3)2(C5H5N)4]·H2O, was isolated from the reaction of 2,6‐pyridinedicarboxylic acid with [Mn12O12(CH3COO)16(H2O)4] in pyridine. The dimanganese complex has twofold symmetry; the MnIII atoms are bridged by one oxo and two amidate ligands and show compressed octahedral Jahn–Teller distortion. The molecular packing comprises a three‐dimensional structure constructed by means of extensive intermolecular interactions, including three kinds of hydrogen bonds and π–π interactions. 相似文献
79.
Yasunori Maekawa 《Journal of Mathematical Analysis and Applications》2009,349(1):181-200
Axisymmetric or non-axisymmetric Burgers vortices have been studied numerically as a model of concentrated vorticity fields. Recently it has been rigorously proved that non-axisymmetric Burgers vortices exist for all values of the vortex Reynolds number if an asymmetry parameter is sufficiently small. On the other hand, several numerical results indicate that Burgers vortices have simpler structures as the vortex Reynolds number is increasing, even when the asymmetry parameter is not sufficiently small. In this paper we give a rigorous explanation for this numerical observation and extend the existence and stability results of Burgers vortices for high vortex Reynolds numbers. 相似文献
80.
Mg-promoted reductive coupling of aromatic carbonyl compounds (1) with chlorosilanes, such as trimethylsilyl chloride (TMSCl:2), 1,2-bis(chlorodimethylsilyl)ethane (3) and 1,5-dichlorohexamethyltrisiloxane (4), in N,N-dimethylformamide (DMF) at room temperature brought about selective and facile reductive formation of both of carbon-silicon and oxygen-silicon bonds to give the corresponding α-trimethylsilylalkyl trimethylsilyl ethers (5) and cyclic siloxanes (6), (7) in moderate to good yields, respectively. The present facile and selective coupling may be initiated through electron transfer from Mg metal to aromatic carbonyl compounds (1). 相似文献