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排序方式: 共有690条查询结果,搜索用时 31 毫秒
71.
Saito K Sogou H Suga T Kusama H Iwasawa N 《Journal of the American Chemical Society》2011,133(4):689-691
Pt(II)-catalyzed generation of unsaturated carbene complex intermediates from various propargyl ether derivatives based on electrophilic activation of alkynes was realized. These in situ generated unsaturated carbene complexes undergo [3+2] cycloaddition reaction with various vinyl ethers, leading to efficient formation of indoles, naphthols, and benzofuran fused with a five-membered ring in high yields. 相似文献
72.
Makio Iwahashi Tadashi Nozaki Kazuyuki Kamaya Kenichi Taguchi Masahiro Fujita Yasutoshi Kasahara Hideyuki Minami Hideyo Matsuzawa Shinji Nakamura Katsuyoshi Harada Yukihiro Ozaki Tohru Inoue 《The Journal of chemical thermodynamics》2011,43(1):80-87
Phase behaviors of the binary mixtures composed of ethylene carbonate (EC) and aliphatic alcohols, ω-phenyl alcohols, and alkylbenzenes were investigated. In addition, heat of solution of EC into these organic solvents was measured. The EC/methanol and EC/ethanol systems gave homogeneous solution at the temperature above their liquidus lines, while the mixtures of EC and alcohols with longer alkyl chain showed a miscibility gap in a liquid phase and provided the monotectic-type phase diagram. The liquid–liquid phase separation region expanded with the increase in the alkyl chain length. A similar phase behavior was also observed for the mixtures of EC and alkylbenzenes. On the other hand, the EC mixtures with ω-phenyl alcohols showed no miscibility gap in a liquid phase at least up to 4-phenylbutan-1-ol which has C4 alkyl chain intervening between phenyl and hydroxyl groups. This result demonstrates that both of the hydroxyl and phenyl groups act to facilitate the mixing of aliphatic compounds with EC. The phase behavior of these EC mixtures was analyzed applying the modified regular solution model in which the pair interaction energy was regarded as free energy. The model calculation with the use of heat of solution of EC at infinite dilution as the pair interaction enthalpy reproduced well both of the experimentally obtained liquidus line and mutual solubility curve as well as monotectic point. 相似文献
73.
Ogawa A Miyamae Y Honma A Koyama T Yazawa K Shigemori H 《Chemical & pharmaceutical bulletin》2011,59(5):672-675
A new compound, pycnalin (1), together with four known compounds, ginnalins A (2), B (3), C (4), and 3,6-di-O-galloyl-1,5-anhydro-D-glucitol (3,6-di-GAG) (5), were isolated from Acer pycnanthum. The structure of 1 was determined on the basis of 2D-NMR spectral data and synthesis of 1. Pycnalin (1) is the first 1,5-anhydro-D-mannitol linked to a gallic acid, while compounds 2-5 were 1,5-anhydro-D-glucitol linked to gallic acids. All compounds were tested in vitro for α-glucosidase inhibitory and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities. Pycnalin (1) exhibited moderate α-glucosidase inhibitory activity as well as free radical scavenging activity. Ginnalin A (2) and 3,6-di-GAG (5), which have two galloyl groups, exhibited potent α-glucosidase inhibition, compared to those of other compounds 1, 3, and 4 containing a galloyl group. These results suggest that α-glucosidase inhibition is influenced by the number of galloyl groups. 相似文献
74.
Ulmann PA Tanaka H Matsuo Y Xiao Z Soga I Nakamura E 《Physical chemistry chemical physics : PCCP》2011,13(47):21045-21049
A [70]fullerene-benzodifuranone acceptor dyad synthesized by a Ag?-mediated coupling reaction was used to construct a thin-film organic solar cell. The fullerene and the benzodifuranone dye in the dyad have close-lying LUMO levels in the range of 3.7-3.9 eV, so that energy transfer from the dye to the fullerene can take place. A p-n heterojunction photovoltaic device consisting of a tetrabenzoporphyrin and a [70]fullerene-benzodifuranone dyad showed a weak but discernible contribution from light absorption of the dyad to the photocurrent under both a positive and a negative effective bias. These results indicate that the benzodifuranone moiety attached to the acceptor contributes to light-harvesting by energy transfer. 相似文献
75.
Graczyk Piotr Ishi Hideyuki Mamane Salha 《Annals of the Institute of Statistical Mathematics》2019,71(2):439-471
Annals of the Institute of Statistical Mathematics - Let G be the graph corresponding to the graphical model of nearest neighbor interaction in a Gaussian character. We study Natural Exponential... 相似文献
76.
The mechanism of GMR effects in La(Mn1–x
Fe
x
)O3 (x=0, 0.01, 0.03) oxides has been investigated by means of magnetic measurements, resistivity measurements in magnetic field and Mössbauer spectroscopy. For the x=0.01 sample, the GMR behavior is similar to that of the conventional (La, A)MnO3 (A: divalent cations) oxides. For the x=0.03 sample, even though the temperature dependence of the Mössbauer spectra was similar to that of the x=0.01 sample, the mechanism for the occurrence of the GMR effect seems to be different. The x=0 sample shows a similar behavior to the x=0.03 sample. A thermal stabilization of spin fluctuation is proposed for the x=0 and x=0.03 sample. 相似文献
77.
Shigeki Habaue Ryo Muraoka Akiko Aikawa Soichiro Murakami Hideyuki Higashimura 《Journal of polymer science. Part A, Polymer chemistry》2005,43(8):1635-1640
The oxidative coupling polymerization of 2,3‐dihydroxynaphthalene with the novel dinuclear‐type copper(II) catalysts successfully produced poly(2,3‐dihydroxy‐1,4‐naphthylene). For example, the MeOH‐insoluble polymer with a number average molecular weight of 4.4 × 103 from the polymerization using the complex of CuCl2 and N,N′‐bis(2‐morpholinoethyl)‐p‐xylylenediamine ( p ‐ 1 ) at room temperature under an O2 atmosphere followed by acetylation of the hydroxyl groups was obtained in 63% yield. The structures of the tetraamine ligands and the counter anion of the copper(II) salts significantly influenced the catalyst activity. The polymerization of 2,2′‐dimethoxy‐1,1′‐binaphthalene‐3,3′‐diol with the 2CuCl2‐ p ‐ 1 catalyst, however, resulted in a lower yield. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1635–1640, 2005 相似文献
78.
Shigeru Nishiyama Yoshikazu Shizuri Daizo Imai Shosuke Yamamura Yukimasa Terada Masatake Niwa Kazuaki Kawai Hideyuki Furukawa 《Tetrahedron letters》1985,26(27):3243-3246
Isocitreoviridinol has been newly isolated from the mycelium of B. (IFO 6050) together with citreoviridinol, and their stereostructures have also been elucidated by means of chemical method: the 2,6-dioxabicyclo[3.2.1]octanes have been made, one of which is regarded as a promising synthetic intermediate of citreoviridinol. In addition, isocitreoviridinol diacetate has been derived from citreoviridin in 3 steps. 相似文献
79.
Irradiation of 5-iodouridine or 6-iodo-1,3-dimethyluracil in aq. acetonitrile in the presence of allyltrimethylsilane provided the corresponding 5- or 6-allylated product. 相似文献
80.