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71.
Two new pregnane glycosides (1, 2) together with two known saponins were isolated from the rhizomes of Dioscorea futschauensis R. KUNTH. The structures of 1 and 2 were established as 16alpha-methoxyl-3beta-[(O-alpha-L-rhamnopyranosyl-(1-->2)-O-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranosyl)oxy]pregn-5-en-20-one and 21-methoxyl-3beta-[(O-alpha-L-rhamnopyranosyl-(1-->2)-O-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranosyl)oxy]pregn-5,16-en-20-one, respectively, on the basis of two-dimension NMR (2D NMR) and other spectral analysis. Their in vitro bioactivity against plant pathogenic fungus Pyricularia oryzae and osteoblastic proliferation stimulatory activity in the UMR106 cell line were evaluated. 相似文献
72.
Hisayoshi Matsushima Adriana Ispas Andreas Bund Waldfried Plieth Yasuhiro Fukunaka 《Journal of Solid State Electrochemistry》2007,11(6):737-743
The electrodeposition process of Co films in a sulfuric acid solution was examined in a magnetic field (0–5 T). The surface
morphology of Co films electrodeposited without a magnetic field was drastically modified with the variation of hydrogen gas
evolution rate. Crystalline α-Co was formed in the range of pH = 1.5–6.0, while β-Co was not observed. When the magnetic field
was superimposed perpendicular to the electric field in the acidic solution (pH = 1.5), the hydrogen evolution rate was promoted
by MHD convection, which enhanced the ionic mass transfer (H+ and Co2+) near the electrode surface. Moreover, crystalline β-Co was formed simultaneously with the appearance of the elongated ridge-shape
precipitates under a higher magnetic field (≥3 T).
Contribution to special issue “Magnetic field effects in Electrochemistry” 相似文献
73.
Based on a special form of the molecular virial theorem, the recently proposed method of momentum density for interatomic interactions is here applied to the problem of molecular geometry. Two molecules BH
2
–
and BH
2
+
, which have the same nuclear framework but favor respectively bent and linear conformations, are comparatively studied. Using an approximate Hartree-Fock momentum density, the total molecular energy (including the nuclear repulsion) is partitioned into orbital components, and a geometry correlation diagram is derived. An atom-bond partitioning of the total energy is also examined based on the one- and two-center decomposition of the momentum density. 相似文献
74.
Morisaki N Kobayashi H Yamamura Y Morisaki M Nagasawa K Hashimoto Y 《Chemical & pharmaceutical bulletin》2002,50(7):935-940
Steroidal allylic alcohols formed Na+ adduct ion peaks [M+Na]+ by the addition of NaCl in FAB mass spectrometry. A comparison of the intensities of the adduct ion peaks of allylic alcohols with those of the corresponding saturated alcohols and olefin suggested that the olefinic double bond and the proximal hydroxyl group had coordinated to Na+. The adduct ion was stable and did not undergo dehydroxylation. We suggest that the Na+ adduction will be useful for the molecular weight determination of allylic alcohols which are susceptible to dehydroxylation under FAB mass spectrometric conditions. Na+ adduct ions of alpha,beta-unsaturated carbonyl compounds were also investigated. 相似文献
75.
Morisaki N Kobayashi H Nagasawa K Baba Y Sodeoka M Hashimoto Y 《Chemical & pharmaceutical bulletin》2003,51(11):1341-1344
The FAB mass spectrum of the Ca(2+) salt of RK-682 (1, MW 368), a potent protein tyrosine phosphatase inhibitor, shows a complex pattern due to Ca(2+) adduct ions with multimers of 1 and their decomposition ions. Addition of LiCl greatly simplified the FAB mass spectrum, providing a prominent Li(+) adduct ion of 1 at m/z 381 [M+2Li-H](+). The addition of LiCl also greatly simplified the FAB mass spectrum of calcium pantothenate. This approach may be generally useful for molecular weight determination of multivalent metal salts of organic compounds, or organic compounds that can form Li salts, by FAB mass spectrometry. 相似文献
76.
Zhi-heng Shu Cai-lian Fan Hong-yan Wei Zi-ting Li Hisayoshi Norimoto Xi-yang Tang Zhi-hong Yao Xin-sheng Yao Yi Dai 《Journal of separation science》2023,46(17):2300331
An efficient strategy for the identification of potential nephroprotective substances in Zhu-Ling decoction has been established with the integration of absorbed components characterization, pharmacokinetics, and activity evaluation. A qualitative method was developed to characterize the chemical constituents absorbed components in vivo of Zhu-Ling decoction by using ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry. A quantitative method was established and validated for the simultaneous determination of eight compounds in rat plasma by using ultra-performance liquid chromatography-triple quadruple tandem mass spectrometry. Finally, the nephroprotective activities of absorbed components with high exposure were assessed by cell survival rate, superoxide dismutase, and malondialdehyde activities in hydrogen peroxide–induced Vero cells. As a result, 111 compounds in Zhu-Ling decoction and 36 absorbed components were identified in rat plasma and urine, and poricoic acid A, poricoic acid B, alisol A, 16-oxo-alisol A, and dehydro-tumulosic acid had high exposure levels in rat plasma. Finally, poricoic acid B, poricoic acid A, 16-oxo-alisol A, and dehydro-tumulosic acid showed remarkable nephroprotective activity against Vero cells damage induced by hydrogen peroxide. Besides, superoxide dismutase and malondialdehyde activities were obviously regulated in hydrogen peroxide–induced Vero cells by treatment with the four compounds mentioned above. Therefore, these four compounds were considered to be effective substances of Zhu-Ling decoction due to their relatively high exposure in vivo and biological activity. This study provided a chemical basis for the action mechanism of Zhu-Ling decoction in the treatment of chronic kidney diseases. 相似文献
77.
Ling Ling Zhao ;Yue Gai ;Hisayoshi Kobayashi ;Chang Qi Hu ;Hui Ping Zhang 《中国化学快报》2008,19(9):1089-1092
A new β-resorcylic macrolide, 5'-hydroxyzearalenol (1), was isolated from the culture broth of a marine-derived fungus Fusarium sp. 05ABR26. Three known compounds, zearalenone (2), 8'-hydroxyzearalenone (3) and zearalenol (4) were also isolated. The structure and relative stereochemistry of 1 were elucidated on the basis of spectroscopic data and single-crystal X-ray diffraction data. Compound 2 displayed potent inhibitory activity against Pyricularia oryzae with a MIC value of 6.25 μg/mL, while compound 3 was much less active; however, 1 and 4 showed no obvious activity. 相似文献
78.
Masayoshi Miyahara Hiroki Shiozaki Hideyuki Tukada Yuichi Ishikawa Masato Oikawa 《Tetrahedron letters》2018,59(48):4259-4262
Herein, we disclose an efficient combination of NPEC and Ns protecting groups in the synthesis of polyamine, by showing the orthogonal reactivity using N-NPEC-N-Ns alkylamines prepared from NPEC-NHNs. Selective photodeprotection of NPEC group in 12-mer polyamine and the complex conjugate has been further demonstrated toward the synthesis of novel polyamine natural product protoaculeine B. 相似文献
79.
80.
A new β-resorcylic macrolide,5′-hydroxyzearalenol(1),was isolated from the culture broth of a marine-derived fungus Fusarium sp.05ABR26.Three known compounds,zearalenone(2),8′-hydroxyzearalenone(3)and zearalenol(4)were also isolated.The structure and relative stereoehemistry of 1 were elucidated on the basis of spectroscopic data and single-crystal X-ray diffraction data.Compound 2 displayed potent inhibitory activity against Pyricularia oryzae with a MIC value of 6.25μg/mL, while compound 3 was much less active;however,1 and 4 showed no obvious activity. 相似文献