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991.
992.
M Iinuma T Tanaka M Mizuno H Yamamoto Y Kobayashi S Yonemori 《Chemical & pharmaceutical bulletin》1992,40(10):2749-2752
Five flavonoid compounds, including two new isoflavanones, were isolated from the root bark of Erythrina x bidwilli. Their structures were determined to be 2,10-di(gamma,gamma-dimethylallyl)-3,9-dihydroxypterocarpan (erythrabyssin II), 6,8-di(gamma,gamma-dimethylallyl)-7,2',4'-trihydroxyisoflavanone (bidwillon A), 8-gamma,gamma-dimethylallyl-2',4'-dihydroxy-[6",6"-di-methylpyrano - (2",3":7,6)]isoflavanone (bidwillon B), 8-gamma,gamma-dimethylallyl-7,4'-dihydroxyisoflavone (8-gamma,gamma-dimethyl-allyldaidzein), and 8-gamma,gamma-dimethylallyl-5,2',4'-trihydroxy-[6",6"-dimethylpyrano+ ++- (2",3":7,6)]isoflavone (auriculatin), by means of spectroscopic analysis. Some potent activities against oral microbial organisms (Fusobacterium nucleatum and Prevotella intermedia) were shown in these flavonoid compounds. 相似文献
993.
994.
Tanahashi T Kobayashi C Itoh A Nagakura N Inoue K Kuwajima H Wu HX 《Chemical & pharmaceutical bulletin》2000,48(3):415-419
From the leaves of Alangium kurzii, a new tetrahydroisoquinoline-monoterpene glucoside, 6-O-methyl-N-deacetylipecosidic acid and a new iridoid glucoside, 10-O-benzoyladoxosidic acid, were isolated along with alangiside, demethylalangiside, 6'-O-beta-D-glucosylhenryoside, uridine and four known flavonoid glycosides. The structures of new glucosides were determined on the basis of spectroscopic and chemical methods. 相似文献
995.
T. Nozaki T. Kobayashi M. Shirai 《Journal of Radioanalytical and Nuclear Chemistry》1996,203(1):151-160
Carrier- and salt-free42K milked from an42Ar–42K generator was utilized for isotope dilution analysis of potassium in ultra-pure water. Potassium in the sample marked with the42K was shown to be concentrated easily 60 times by crown-ether extraction and acid back-extraction to be determined by atomic absorption spectrophotometry. The same extractions proved to be effective for removing the reagent blank. Cerenkov radiation counting was often suitable for42K measurement. The42K was used also for studying the interaction of ultra-low concentrations of potassium with vessel walls. 相似文献
996.
The transition between phase I and phase III in sodium sulfate (Na2SO4) was studied by high temperature X-ray diffraction and the calculation of diffraction patterns. An intermediate phase (phase II) was detected on cooling in the undoped and 1.7 at.% yttrium-doped Na2SO4, but not observed in the 3.8 at.% Y-doped sample. The DTA and X-ray diffraction results of the III ? I transition were explained well by a proposed model which consisted mainly of the following steps: (i) the rotation of the SO4 tetrahedra, and (ii)the disappearance of interfaces among the transformed domains. 相似文献
997.
Binary mixtures of acetylacetone and 8-hydroxyquinoline chelates of copper(II), nickel(II), cobalt(II) and cobalt(III) were processed by zone-chromatography on columns of some naphthylalkyl ethers as inert solid solvents. The metal chelates were separated to give chromatograms on the columns according to the ratio of their distribution coefficients. Distribution coefficients of metal ions varied with the type of chelating agent used and the solid solvent, and were found to be strongly affected by operating conditions, especially zone length, zone travelling speed and initial concentration of the metal chelate. 相似文献
998.
The absolute stereostructure of komodoquinone A (1), a neuritogenic anthracycline, which was isolated from a cultured marine Streptomyces sp. KS3, has been determined on the basis of chemical derivatization. Komodoquinone A (1) induces neuronal cell differentiation in the neuroblastoma cell line, Neuro 2A and arrests the cell cycle at the G1 phase. The effect of a solid-state medium on the production of 1 and its aglycone, komodoquinone B (2), was examined. 相似文献
999.
N. Takezawa M. Shimokawabe H. Hiramatsu H. Sugiura T. Asakawa H. Kobayashi 《Reaction Kinetics and Catalysis Letters》1987,33(1):191-196
Cu/ZrO2 was highly active and selective for the title reaction. The activity obtained exceeded greatly that obtained over Cu/SiO2. It was shown that the precursors highly dispersed on zirconia support were readily reduced to very fine particles of metallic copper.
Cu/ZrO2 . Cu/SiO2. , , , .相似文献
1000.
Dohi H Nishida Y Furuta Y Uzawa H Yokoyama S Ito S Mori H Kobayashi K 《Organic letters》2002,4(3):355-357
Galacto-type trehalose, a "C-4 epimer of trehalose", possesses a stereochemical structure around the alpha(1-1)-linkage analogous to that of the globobiosyl alpha(1-4)-linkage in Gb(2) and Gb(3) ceramides, which are known as the ligands of Shiga toxins produced by pathogenic E. coli. This paper presents evidence supporting the new idea of using a trehalosyl alpha(1-1)-linkage as a substitute for the galactobiosyl alpha(1-4)-linkage. 相似文献