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Kiyotomi Kaneda Kazuya Yamaguchi Kohsuke Mori Tomoo Mizugaki Kohki Ebitani 《Catalysis Surveys from Japan》2000,4(1):31-38
Various Mg-Al type hydrotalcites were examined as catalysts for the epoxidation of olefins and N-oxidation of pyridines using hydrogen peroxide. The catalytic activity of hydrotalcites increased with increasing the basicity of their surface. Adding cationic surfactants, e.g., n-dodecyltrimethylammonium bromide, to the above system remarkably accelerated the reaction rate. The hydrotalcites, into which were introduced both Ru and Co cations in the Brucite layers, were found to be good catalysts for the oxidation of various alcohols in the presence of molecular oxygen. Moreover, these hydrotalcites could smoothly catalyze also the oxygenation of diphenylmethane, fluorene, and xanthene at benzylic position with excellent yields. The hydrotalcite catalysts could be easily separated from the reaction mixture and reused with retention of their high catalytic performance for the above oxidations. 相似文献
13.
Tsutomu Konno Tomoo Tanaka Tomotsugu Miyabe Atsunori Morigaki Takashi Ishihara 《Tetrahedron letters》2008,49(13):2106-2110
Treatment of fluoroalkylated electron-deficient olefins with various boronic acids in the presence of a catalytic amount of Rh(I) coordinated with (S)-BINAP in toluene/H2O at the reflux temperature for 3 h gave the corresponding conjugate addition products with high enantioselectivity in high yields. 相似文献
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Masayuki Yamada Sugako Aramaki Tomoo Hosoe Masahiko Kurosawa Isao Kijima-Suda Koichi Saito Hiroyuki Nakazawa 《Analytical sciences》2008,24(7):911-914
Fluoxymesterone, an anabolic steroid with the 17alpha-methyl,17beta-hydroxy group, has been developed as an oral formulation for therapeutic purposes. However, it is also used illegally in racehorses to enhance racing performance. In this study, we detected 9alpha-fluoro-17,17-dimethyl-18-norandrostane-4,13-dien-11beta-ol-3-one by gas chromatography/mass spectrometry (GC/MS), which has not been reported as a fluoxymesterone metabolite so far in horse. It was synthesized for use as a reference standard, and characterized on the basis of (1)H NMR and (13)C NMR spectra, as well as GC/MS EI mass spectra of TMS derivatives. It was excreted as the main metabolite in horse urine, and its reference standard could be synthesized easily. Therefore, this metabolite could be a useful target for a doping test of fluoxymesterone in racehorses. 相似文献
16.
A proposed structure for the diffusible extracellular factor (DF) of Xanthomonas campestris pv. campestris (Xcc) has been synthesized. Its MS spectrum and biological activity, however, contradict those of the natural product previously reported, suggesting that the structure for DF of Xcc must be reexamined. 相似文献
17.
Katsuhiko Takenaka Natsuyo Shibata Akihiko Oshikiri Masamitsu Miya Hiroki Takeshita Tomoo Shiomi 《Journal of polymer science. Part A, Polymer chemistry》2010,48(17):3714-3721
Anionic polymerizations of three 1,3‐butadiene derivatives containing different N,N‐dialkyl amide functions, N,N‐diisopropylamide (DiPA), piperidineamide (PiA), and cis‐2,6‐dimethylpiperidineamide (DMPA) were performed under various conditions, and their polymerization behavior was compared with that of N,N‐diethylamide analogue (DEA), which was previously reported. When polymerization of DiPA was performed at ?78 °C with potassium counter ion, only trace amounts of oligomers were formed, whereas polymers with a narrow molecular weight distribution were obtained in moderate yield when DiPA was polymerized at 0 °C in the presence of LiCl. Decrease in molecular weight and broadening of molecular weight distribution were observed when polymerization was performed at a higher temperature of 20 °C, presumably because of the effect of ceiling temperature. In the case of DMPA, no polymer was formed at 0 °C and polymers with relatively broad molecular weight distributions (Mw/Mn = 1.2) were obtained at 20 °C. The polymerization rate of PiA was much faster than that of the other monomers, and poly(PiA) was obtained in high yield even at ?78 °C in 24 h. The microstructure of the resulting polymers were exclusively 1,4‐ for poly(DMPA), whereas 20–30% of the 1,2‐structure was contained in poly(DiPA) and poly(PiA). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3714–3721, 2010 相似文献
18.
Solute diffusion coupled with an orthogonal laminar flow has been systematically studied with wide-bore capillaries to establish its limitations and reveal its potentials as separation methodology requiring neither chemical nor physical interactions. Simulations based on the advection-diffusion equation in a cylindrical coordinate system indicate several important features of this potentially useful method: (1) if a solute diffuses over the entire cross-section of the capillary before it is eluted from the capillary, it behaves as a diffusive solute and gives a Gaussian-shaped peak (diffusion peak) having an apex at the traveling time of the average flow; (2) when a solute is poorly (or not) diffusive, a new peak appears with an apex at the elution time of the maximum flow (non-diffusion peak); (3) these two peaks are simultaneously detected for intermediately diffusive solutes; (4) the transformation from the diffusion to non-diffusion peak occurs when the solute diffuses over the distance 0.86 times as large as the capillary radius before it leaves the capillary. These results of simulations are consistent with experimental results for selected solutes having various diffusivities. This method has proved useful particularly for the evaluation of diffusion coefficients of poorly diffusive solutes. Separation of PS particles having different sizes is also attempted. 相似文献
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20.
A 1-l water sample was concentrated to 20ml by freezing and analyzed for soluble, colloidal and insoluble silica by the spectrophotometric heteropoly blue method and by inductively coupled plasma/atomic emission spectrometry. High-purity water obtained from a vitreous-silica sub-boiling distillation still contained a few micrograms of insoluble silica per liter. 相似文献