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81.
Dr. Yasuo Tanaka Dr. Tomoki Yoneda Prof. Dr. Ko Furukawa Dr. Taro Koide Hirotaka Mori Dr. Takayuki Tanaka Prof. Dr. Hiroshi Shinokubo Prof. Dr. Atsuhiro Osuka 《Angewandte Chemie (International ed. in English)》2015,54(37):10908-10911
A ZnII‐CuI‐ZnII heterotrimetal complex of decaphyrin was synthesized by stepwise metalations: metalation of a [46]decaphyrin with ZnII ions to produce a 46π decaphyrin bis(ZnII) complex and its subsequent metalation with CuII ion. In the second metalation step, it has been shown that CuII ion is reduced to a CuI ion in the complex and a dianionic bis(ZnII) containing [46]decaphyrin ligand is oxidized to the corresponding monoanionic [45]decaphyrin ligand, indicating a non‐innocent nature of the decaphyrin ligand. Despite the radical nature, the heterotrimetal complex is fairly stable under ambient conditions and exhibits almost no intermolecular magnetic interaction, owing to extensive delocalization of an unpaired electron in the large π‐conjugated circuit of decaphyrin moiety. 相似文献
82.
83.
K Koide J M Finkelstein Z Ball G L Verdine 《Journal of the American Chemical Society》2001,123(3):398-408
Small molecules that induce or stabilize the association of macromolecules have proven to be useful effectors of a wide variety of biological processes. To date, all examples of such chemical inducers of dimerization have involved known ligands to well-characterized proteins. The generality of this approach could be broadened by enabling the discovery of heterodimerizers that target known macromolecules having no established ligand, or heterodimerizers that produce a novel biologic response in screens having no predetermined macromolecular target. Toward this end, we report the construction of a diversified library of synthetic heterodimerizers consisting of an invariant ligand that targets the FK506-binding protein (AP1867) attached to 320 substituted tetrahydrooxazepines (THOXs). The THOX components were generated by a combination of liquid- and solid-phase procedures employing sequential Mitsonobu displacements to join two structurally diversified olefin-containing monomers, followed by ruthenium-mediated olefin metathesis to effect closure of the seven-membered ring. The 320 resin-bound THOX ligands were coupled in parallel to AP1867, and the products were released from the resin to yield candidate heterodimerizers in sufficient yield and purity to be used directly in biologic testing. A representative panel of 25 candidate heterodimerizers were tested for their ability to pass through the membrane of human fibrosarcoma cells, and all were found to possess activity in this tissue culture system. These studies pave the way for further studies aimed at using small-molecule inducers of heterodimerization to effect novel biological responses in intact cells. 相似文献
84.
The aim of the present study was to mask the bitterness of propiverine hydrochloride (P-4) by converting it to propiverine free base. Fine granules comprising the free base, which was converted from P-4 by desalination, were prepared. By using Fourier transform infrared spectroscopy, thermogravimetry-differential thermal analysis, and powder X-ray diffraction spectra, we confirmed that P-4 had been converted into propiverine free base by desalination during the manufacturing process. Furthermore, the conversion into free base appeared to result in decreased solubility, and both the taste testing sensor and tasting volunteers determined that it masked the bitterness of P-4. On using the gustatory sensation test, the bitterness of the P-4 fine granules was confirmed to be weakened. The dissolution rate and bioavailability of fine granules of the free base were compared with tablets of P-4. The dissolution rate and bioavailability of the fine granules and tablets were almost the same. We successfully masked the taste of P-4 by converting it into free base using a manufacturing process that was suitable for commercial manufacturing. 相似文献
85.
Mohamed Boutchich José Alvarez Djicknoum Diouf Pere Roca i Cabarrocas Meiyong Liao Imura Masataka Yasuo Koide Jean-Paul Kleider 《Journal of Non》2012,358(17):2110-2113
We have fabricated and characterized diamond based heterojunctions composed of homoepitaxial diamond (B-doped film: p type) and hydrogenated amorphous silicon (a-Si:H film: n-type). All devices include an intrinsic amorphous silicon interface (i-a-Si:H). (J–V) characteristics of a-Si:H heterojunctions measured from 300 K to 460 K present a very high rectification ratio (in the range 108–109) and a current density of 10 mA/cm² under 2 V of forward bias. The reverse current up to ? 4 V is below the detection limit in the whole temperature range. The devices present two regimes of operation indicating that more than one mechanism governs the carrier transport. These characteristics are compared with a Schottky barrier diode (SBD) using a tungsten carbide metal on top of the p-type diamond as a Schottky contact. The SBD device exhibits J–V characteristic with an ideality factor n close to one and the heterojunction follows this trend for low bias voltages whereas for bias voltage above 1 V a second regime with larger ideality factors n ~ 3.6 is observed. These results point out the prominent role of transport mechanisms at heterointerface between the a-Si:H layers and the p-type doped diamond which degrades the current injection. The breakdown voltage reached ? 160 V indicating the good quality of the deposited layers. 相似文献
86.
Nishikawa T Koide Y Kanakubo A Yoshimura H Isobe M 《Organic & biomolecular chemistry》2006,4(7):1268-1277
alpha-C-Mannosyltryptophan (alpha-C-Man-Trp) has been found to be a novel post-translational modification of tryptophan found from some biologically important glycoproteins. In order to analyze the biological functions of alpha-C-Man-Trp, we have developed an efficient synthetic strategy for alpha-C-Man-Trp and its glucose and galactose analogues, starting from alpha-C-glycosidation of the corresponding hexapyranoside derivatives with tinacetylene. According to the synthetic routes, we describe here syntheses of beta-anomers of C-Man-Trp, and its glucose and galactose analogues from the corresponding beta-C-glycosylacetylenes. During this study, we have developed a highly stereocontrolled synthesis of beta-C-mannosylacetylene that is required for the synthesis of beta-C-Man-Trp, while the precedented method gave an anomeric mixture of the C-mannosylacetylene. The synthetic C-Man-Trp and its analogues were analyzed by HPLC. 相似文献
87.
Treatment of AlO(OH) with 3 equiv of 8-hydroxyquinolinol in refluxing deionized water provided the meridional and facial isomers of tris(8-hydroxyquinolinate)aluminum (Alq3) with good yields as solid deposits after 1 and 90 h, respectively. X-ray diffraction and solid-state 13C NMR studies revealed that mer-Alq3 is formed in the early stage of the reaction and then gradually converts to fac-Alq3, which is thermodynamically less stable, although no existence of a catalyst substance is implied. 相似文献
88.
We rederive the equations of motion of dissipative relativistic fluid dynamics from kinetic theory. In contrast with the derivation of Israel and Stewart, which considered the second moment of the Boltzmann equation to obtain equations of motion for the dissipative currents, we directly use the latter's definition. Although the equations of motion obtained via the two approaches are formally identical, the coefficients are different. We show that, for the one-dimensional scaling expansion, our method is in better agreement with the solution obtained from the Boltzmann equation. 相似文献
89.
90.
K. Yokoi Maki Yakushiji Mayumi Hatanaka Koji Kubono Tsutomu Koide 《Fresenius' Journal of Analytical Chemistry》1999,365(4):364-367
A high output low-pressure mercury lamp, 400 W L-Hg, was successfully used for the photolytic decomposition of dissolved
oganic compounds as the pretreatment for the determination of trace metal ion in aqueous solution by stripping voltammetry.
Various amino acids, showing interferences on voltammetric determination of metal ions, can be removed quite easily by intensive
UV irradiation at room temperature. Effect of pH, concentration of electrolyte and dissolved oxygen on the efficiency of photolysis
are also described. This method uses no additional chemicals such as acids or oxidants and can be carried out in closed clean
conditions.
Received: 1 February 1999 / Revised: 19 April 1999 / Accepted: 5 May 1999 相似文献