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171.
Blepharismins, toxic pigments of the ciliate Blepharisma japonicum, are polycyclic ring-condensed compounds. Assignment of 13C NMR signals for blepharismin C, a major constituent of blepharismins, was achieved by analyses of the HMQC, HMBC, and INADEQUATE spectra of 13C-enriched samples obtained by feeding experiments using sodium [1-13C], [2-13C], and [1,2-13C2]acetates. 相似文献
172.
Synthesis and biological evaluation of quinuclidine derivatives incorporating phenothiazine moieties as squalene synthase inhibitors 总被引:1,自引:0,他引:1
Ishihara T Kakuta H Moritani H Ugawa T Yanagisawa I 《Chemical & pharmaceutical bulletin》2004,52(10):1204-1209
Squalene synthase inhibitors have the potential to be superior hypocholesterolemic agents. A series of quinuclidine derivatives incorporating phenothiazine systems was synthesized in order to investigate the effects of their structure on the inhibition of hamster liver microsomal enzyme. (+/-)-3-(10-Methyl-10H-phenothiazin-3-ylmethoxy)quinuclidine hydrochloride (19) was the most potent inhibitor in this series with an IC(50) value of 0.12 microM. Oral dosing of compound 19 to hamsters demonstrated effective reduction of both plasma total cholesterol levels and plasma triglyceride levels. Compound 19 showed a reduced tendency to elevate plasma transaminase levels, an indicator of hepatotoxicity. Enantiomerically pure (-)-19, YM-53546, was found to be more potent than the corresponding (+)-enantiomer. 相似文献
173.
Iiduka Y Wakahara T Nakahodo T Tsuchiya T Sakuraba A Maeda Y Akasaka T Yoza K Horn E Kato T Liu MT Mizorogi N Kobayashi K Nagase S 《Journal of the American Chemical Society》2005,127(36):12500-12501
We report here the structural determination of the Sc3C82 molecule by 13C NMR spectroscopy and X-ray single-crystal structure analysis. From the present study, it is obvious that the structure of Sc3C82 is not Sc3@C82 but Sc3C2@C80. 相似文献
174.
Akasaka T Kono T Takematsu Y Nikawa H Nakahodo T Wakahara T Ishitsuka MO Tsuchiya T Maeda Y Liu MT Yoza K Kato T Yamamoto K Mizorogi N Slanina Z Nagase S 《Journal of the American Chemical Society》2008,130(39):12840-12841
We report here the results on single crystal X-ray crystallographic analysis of the Gd@C82 carbene adduct (Gd@C82(Ad), Ad = adamantylidene). The Gd atom in Gd@C82(Ad) is located at an off-centered position near a hexagonal ring in the C2v-C82 cage, as found for M@C82 (M = Sc and La) and La@C82(Ad). Theoretical calculation also confirms the position of the Gd atom in the X-ray crystal structure. 相似文献
175.
Tsukasa Tawatari Ritsuki Kato Riku Kudo Prof. Dr. Kiyosei Takasu Prof. Dr. Hiroshi Takikawa 《Angewandte Chemie (International ed. in English)》2023,62(19):e202300907
We report herein intramolecular (3+2) cycloaddition reactions between ynamides as three-atom components and benzyne. In these intramolecular reactions, the two-bond formation is realized by exploiting benzyne precursors that contain a chlorosilyl group as a linking functionality. This method thus highlights the ambivalent character of the intermediate indolium ylide, which exhibits both nucleophilic and electrophilic properties at its C2 atom. 相似文献
176.
Satoshi Arimoto Daisuke Oyamatsu Dr. Tsukasa Torimoto Prof. Susumu Kuwabata Prof. 《Chemphyschem》2008,9(5):763-767
We report that ionic liquids (ILs) can be observed by electron microscopy without any charging of the liquid. Based on this, we present an in situ electrochemical scanning electron microscopy (in situ ECSEM) system. The key technology that enables in situ ECSEM is that charges can be removed from an IL by grounding it with a Pt wire, even if the IL is in an insulating glass cell. As a first demonstration, we describe the redox reaction of a polypyrrole (PPy) film accompanied by changes in its thickness when it is polarized by the film‐deposited Pt electrode in the IL. Furthermore, energy‐dispersive X‐ray fluorescence (EDX) analysis can be employed for the electrode polarized in the IL. The component analysis by EDX of PPy in an IL containing K+ as a marker, reveals doping of electrolyte cations into the PPy film upon the latter′s reduction and dedoping of cations from the film upon oxidation. 相似文献
177.
Khatri OP Adachi K Murase K Okazaki K Torimoto T Tanaka N Kuwabata S Sugimura H 《Langmuir : the ACS journal of surfaces and colloids》2008,24(15):7785-7792
Ultrafine monodisperse gold nanoparticles (AuNPs) were synthesized by an elegant sputtering of gold onto 1- n-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF(6)) ionic liquid. It was found that the BMI-PF(6) supramolecular aggregates were loosely coordinated to the gold nanoparticles and were replaceable with thiol molecules. The self-assembly of BMI-PF(6)-stabilized AuNPs onto a (3-mercaptopropyl)trimethoxysilane (MPS)-functionalized silicon surface in 2D arrays, followed by dodecanethiol (DDT) treatment, have been demonstrated using X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and contact angle measurements. DDT treatment of tethered AuNPs revealed two types of interactions between AuNPs and the MPS-functionalized surface: (a) AuNPs anchor through Au-S chemisorption linkage resulting in strong immobilization and (b) some of the AuNPs are supported by physisorption, driven by BMI-PF(6). The attachment of these particles remains unchanged with sonication. The replacement of BMI-PF(6) aggregates from physisorbed AuNPs with DDT molecules advances the dilution of their interaction with the MPS-functionalized surface, and they subsequently detach from the silicon surface. The present finding is promising for the immobilization of ionic liquid-stabilized nanoparticles, which is very desirable for electronic and catalytic device fabrication. Additionally, these environmentally friendly AuNPs are expected to replace conventional citrate-stabilized AuNPs. 相似文献
178.
Nikawa H Kikuchi T Wakahara T Nakahodo T Tsuchiya T Rahman GM Akasaka T Maeda Y Yoza K Horn E Yamamoto K Mizorogi N Nagase S 《Journal of the American Chemical Society》2005,127(27):9684-9685
The first isolation of missing metallofullerene, La@C74, as a derivative is reported. The structural determination has been performed by spectroscopic and, finally, X-ray crystallographic analysis, and the properties of La@C74 are discussed on the basis of the theoretical study. 相似文献
179.
Ota T Rontani M Tarucha S Nakata Y Song HZ Miyazawa T Usuki T Takatsu M Yokoyama N 《Physical review letters》2005,95(23):236801
We study electronic configurations in a single pair of vertically coupled self-assembled InAs quantum dots, holding just a few electrons. By comparing the experimental data of nonlinear single-electron transport spectra in a magnetic field with many-body calculations, we identify the spin and orbital configurations to confirm the formation of molecular states by filling both the quantum mechanically coupled symmetric and antisymmetric states. Filling of the antisymmetric states is less favored with increasing magnetic field, and this leads to various magnetic field induced transitions in the molecular states. 相似文献
180.
The tris(arylthiolate) vanadium(III) complex (1) has been synthesized in good yield. This complex is found to undergo CH activation across a V-S bond in the presence of TMEDA to give a cyclometalated species along with free arylthiol. Complex 1 behaves as a two-electron reductant toward Ad-N(3), yielding an imide complex. Treatment of 1 with azobenzene produces an imide-sulfenamide compound, in which an azo N=N bond cleavage takes place concomitant with formation of a V=N and an S-N bond. 相似文献