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排序方式: 共有168条查询结果,搜索用时 15 毫秒
1.
Li-Ngee Ho Tasuku Ikegawa Hiroyasu Nishiguchi Katsutoshi Nagaoka Yusaku Takita 《Applied Surface Science》2006,252(18):6260-6268
A synthesis of molybdenum incorporated mesoporous aluminophosphate with long-chain n-alkylamine as template material had been prepared under non-aqueous condition. These materials were extensively characterized by using X-ray diffraction (XRD), nitrogen sorption isotherms, nuclear magnetic resonance of 27Al and 31P (NMR), inductive coupled plasma (ICP), electron spin resonance (ESR), Fourier transform infrared (FTIR) and thermogravimetric-differential thermal analysis (TG-DTA). Morphology of the materials had been observed by using transmission electron microscope (TEM) that revealed the mesoporous materials possessed wormhole-like structures. Alkaline solvent extraction using n-butylamine/ethanol had been efficiently removed the n-alkylamine from the mesoporous samples which yielded BET surface areas around 550-730 m2/g. BJH analysis showed a narrow pore size distribution which increased with increasing of the carbon chain length of alkylamine (template). Valence state and coordination of the molybdenum in the obtained samples were investigated by using ESR and FTIR where it was found that Mo4+ and Mo6+ molybdenum species existed in the molybdenum incorporated mesoporous aluminophosphate in tetrahedral coordination. 相似文献
2.
Oguchi T Tozuka Y Hanawa T Mizutani M Sasaki N Limmatvapirat S Yamamoto K 《Chemical & pharmaceutical bulletin》2002,50(7):887-891
The solid-state complexation between cholic acid (CA) and either methyl p-hydroxybenzoate (MPB) or ibuprofen (IBP) was investigated. Powder X-ray diffractometry, IR spectroscopy and thermal analysis suggested the complex formation between CA and MPB as well as between CA and IBP by co-grinding method. The stoichiometry of CA-MPB was 1 : 1 while that of CA-IBP was 2 : 1, reflecting the effect of guest size on complex formation. The guest compounds were assumed to be included in the channel of complexes formed by hydrogen bonds among CA molecules. 相似文献
3.
Influence of isosorbide dinitrate concentration on its skin permeability from adhesive matrix devices. 总被引:2,自引:0,他引:2
T Hatanaka M Oguchi K Sugibayashi Y Morimoto 《Chemical & pharmaceutical bulletin》1991,39(7):1802-1805
Adhesive matrix devices containing a model drug, isosorbide dinitrate (ISDN), were prepared with three different types of pressure sensitive adhesives (PSAs). ISDN permeation through excised hairless rat skin from the different devices was measured in vitro. For each PSA type, the steady state permeation rate of ISDN increased proportionally with an increase of ISDN concentration in the PSA and reached a maximum level at a certain concentration. Although the concentrations reaching the maximum skin permeation level varied among PSA types, the maximum rate for each PSA type was largely similar to that for ISDN aqueous suspension. The release rate of ISDN from devices was too fast to influence the skin permeation rate for all devices. In the PSA of devices showing maximum skin permeability, ISDN crystalline was observed by polarizing microscopy and differential scanning calorimetry. These results suggest that the skin permeation of ISDN from adhesive matrix devices was controlled by the thermodynamic activity of the drug in the PSAs. 相似文献
4.
Characterization of clarithromycin polymorph was performed by solid-state cross polarization and magic angle spinning (CP/MAS) 13C-NMR spectroscopy. Two polymorphs, form II and form I, of clarithromycins indicated characteristic resonances of C1 carbonyl carbon at 176.2 and 175.2 ppm, respectively. Since each peak of C1 carbon was well separated in the spectrum of the two polymorphs, we performed quantitative analysis of the polymorphic fraction from the peak area of these peaks. The peak area of form I was found to linearly increase with an increase of its content, with a correlation coefficient of above 0.99. Solid-state NMR was found to be a useful technique to determine the characteristics of the polymorphic forms. 相似文献
5.
Moribe K Tsuchiya M Tozuka Y Yamaguchi K Oguchi T Yamamoto K 《Chemical & pharmaceutical bulletin》2004,52(5):524-529
We prepared and characterized a grinding-induced equimolar complex of thiourea with ethenzamide. When thiourea and ethenzamide were co-ground at a molar ratio of 3 : 1, new powder X-ray diffraction (PXRD) peaks were observed in addition to PXRD peaks of thiourea crystals. The optimum stoichiometry of the new structure was confirmed as 1 : 1 mol/mol. Effect of grinding time on the thiourea-ethenzamide equimolar complex formation was investigated by using PXRD, differential scanning calorimetry and Fourier transform infrared spectroscopy. The equimolar crystal structure was confirmed by X-ray diffraction measurements of the single crystal which was recrystallized from ethanol. It was found that the intermolecular hydrogen bond formations between thiourea and ethenzamide molecules contributed to the equimolar complex formation. The complex formation was not observed in the cases where benzamide, salicylamide or 3-ethoxybenzamide was co-ground with thiourea. 2-Alcoxyl benzamide structures should be required for the grinding-induced equimolar complex formation with thiourea. 相似文献
6.
Sontaya Limmatvapirat Etsuo Yonemochi Toshio Oguchi Keiji Yamamoto 《Journal of inclusion phenomena and macrocyclic chemistry》1998,31(4):367-379
A complex between deoxycholic acid (DCA) and salicylic acid (SA) was prepared by grinding and coprecipitation methods. The resultant complex was characterized by means of powder X-ray diffractometry, IR spectroscopy and thermal analysis. The stoichiometry (DCA : SA 1 : 1) of the complex obtained by grinding was identical to that obtained by coprecipitation. The powder X-ray diffraction pattern of the DCA–SA complex differed from the typical pattern of DCA–guest complexes such as DCA–camphor and DCA–phenanthrene complexes. IR spectra suggested that a different kind of hydrogen bonding was formed in the crystal of the DCA–SA complex, compared with the other DCA–guest complexes. This was in good agreement with data from the crystal structure. 相似文献
7.
Hiroyasu Nishiguchi Hiroshi Yamada Masaru Ogura Tatsumi Ishihara Yusaku Takita 《Research on Chemical Intermediates》2003,29(7-9):755-760
The oxygen storage capacity of CeO2, Ce0.9Pr0.1O2, Pt?Rh/CeO2 and Pt?Rh/Ce0.9Pr0.1O2 was investigated by conventional GC pulse method and transient pulse techniques. It is shown that incorporation of PrOy into CeO2 matrix strongly promotes oxygen storage capacity (OSC) measured using the transient pulse technique. The improvement of OSC at low temperature is observed in Pt?Rh loaded onto CeO2 and Ce?Pr catalysts. 相似文献
8.
Sakurai J Oguchi T Watanabe K Abe H Kanno S Ishikawa M Katoh T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(3):829-837
Biologically important and structurally unique marine natural products avarone (1), avarol (2), neoavarone (3), neoavarol (4) and aureol (5), were efficiently synthesized in a unified manner starting from (+)-5-methyl-Wieland-Miescher ketone 10. The synthesis involved the following crucial steps: i) Sequential BF(3)Et(2)O-induced rearrangement/cyclization reaction of 2 and 4 to produce 5 with complete stereoselectivity in high yield (2 --> 5 and 4 --> 5); ii) strategic salcomine oxidation of the phenolic compounds 6 and 8 to derive the corresponding quinones 1 and 3 (6 --> 1 and 8 --> 3); and iii) Birch reductive alkylation of 10 with bromide 11 to construct the requisite carbon framework 12 (10 + 11 --> 12). An in vitro cytotoxicity assay of compounds 1-5 against human histiocytic lymphoma cells U937 determined the order of cytotoxic potency (3 > 1 > 5 > 2 > 4) and some novel aspects of structure-activity relationships. 相似文献
9.
Tomohiro Sakata Shingo Ogawa Keiko Inoue Yumiko Shimizu Yusaku Tanahashi 《Surface and interface analysis : SIA》2022,54(6):661-666
To systematically evaluate the quality of SiNx films in multi-stacked structures, we investigated the effects of post-deposition annealing (PDA) on the film properties of SiNx within the SiO2/SiNx/SiO2/Si stacked structure by performing X-ray photoelectron spectroscopy (XPS), X-ray reflectivity (XRR), Fourier transform infrared (FT-IR) spectroscopy, and scanning transmission electron microscope–electron energy loss spectroscopy (STEM-EELS) analyses. The XPS results showed that PDA induces the oxidation of the SiNx layer. In particular, new finding is that Si-rich SiNx in the SiNx layer is preferentially oxidized by PDA even in multi-stacked structure. The XRR results showed that the SiNx layer becomes thinner, whereas the interface layer between the SiNx layer and Si becomes thicker. It is concluded by STEM-EELS and XPS that this interface layer is SiON layer. The density of N–H and Si–H bonding within the stacked structure strongly depends on the PDA temperature. Our study helps elucidate the properties of SiNx films in stacked structures from various perspectives. 相似文献
10.
Dr. Yusaku Nomura Dr. Frédéric Thuaud Dr. Daisuke Sekine Prof. Dr. Akihiro Ito Satoko Maeda Dr. Hiroyuki Koshino Dr. Daisuke Hashizume Dr. Atsuya Muranaka Dr. Thomas Cruchter Prof. Dr. Masanobu Uchiyama Prof. Dr. Satoshi Ichikawa Prof. Dr. Akira Matsuda Prof. Dr. Minoru Yoshida Prof. Dr. Go Hirai Prof. Dr. Mikiko Sodeoka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(35):8387-8392
A synthetic methodology to access all possible stereoisomers of spectomycin A1 (SMA1) and A2 (SMA2) has been established through late-stage diversification. The key reaction for the construction of all four diastereomers is an intramolecular cyclization based on the umpolung of π-allyl palladium species with bis(pinacolato)diborane (B2(pin)2). Silyl group assisted direct benzylic oxidation of each isomer enabled construction of the fragile β-hydroxytetralone skeleton to provide the SMAs. The relative and absolute stereochemistry of SMA2 was also determined, and the absolute stereochemistry of SMA1 was extrapolated based on the optical rotation of SMA2. The axial chirality of SMAs is discussed based on circular dichroism spectra and DFT calculations, and it is concluded that the M isomer is predominant in solution. Biochemical assessment of all isomers in vitro revealed that the C9 hydroxyl group and dimeric structure were both important for protein SUMOylation-inhibitory activity. 相似文献