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211.
The reactivities of twelve major anthocyanins identified in bilberry extracts towards nitric oxide (NO.) and peroxynitrite (ONOO-) were studied in vitro using capillary zone electrophoresis (CZE). The reactivities of the anthocyanins towards NO. were slightly weak compared with that of (+)-catechin as a reference antioxidant under anaerobic conditions except delphinidin glycosides (Dp3glys). The reactivities of other anthocyanins were not significantly affected by either the aglycon structure or the type of sugar moiety. Under aerobic conditions, all anthocyanins and catechin showed significant enhancement of the reactivity, indicating that they reacted with other reactive species secondarily generated from NO. . Dp3glys showed rather extraordinally high reactivity towards ONOO- compared to other anthocyanins which showed approximately two times low reactivity than catechin when compared with IC50. Structural divergence in the reactivity was also small for all these anthocyanins. 相似文献
212.
[reaction: see text] Highly selective cross [2 + 2 + 2] cycloaddition of two different monoynes is achieved by using a catalytic amount of [Ir(cod)Cl](2) and ligand. The ligand had a considerable effect on the reaction. When 1,2-bis(diphenylphosphino)ethane was used, two molecules of dimethyl acetylenedicarboxylate (DMAD) reacted with one molecule of a monoyne to give the 2:1 coupling product. When 1,2-bis(dipentafluorophenylphosphino)ethane was used instead of dppe, one molecule of DMAD reacted with two molecules of a monoyne to give the 1:2 coupling product. 相似文献
213.
Daisuke Takeuchi Yoshihiko Sakaguchi Kohtaro Osakada 《Journal of polymer science. Part A, Polymer chemistry》2002,40(24):4530-4537
Co2(CO)8 catalyzes the ring‐opening copolymerization of propylene oxide with CO to afford the polyester in the presence of various amine cocatalysts. The 1H and 13C{1H} NMR spectra of the polyester, obtained by the Co2(CO)8–3‐hydroxypyridine catalyst, show the following structure ? [CH2? CH(CH3)? O? CO]n? . The Co2(CO)8–phenol catalyst gives the polyester, which contains the partial structural unit formed through the ring‐opening copolymerization of tetrahydrofuran with CO. The bidentate amines, such as bipyridine and N,N,N′,N′‐tetramethylethylenediamine, enhance the Co complex‐catalyzed copolymerization, which produces the polyester with a regulated structure. Acylcobalt complexes, (RCO)Co(CO)n (R = Me or CH2Ph), prepared in situ, do not catalyze the copolymerization even in the presence of pyridine. This suggests that the chain growth involves the intermolecular nucleophilic addition of the OH group of the intermediate complex to the acyl–cobalt bond, forming an ester bond rather than the insertion of propylene oxide into the acyl–cobalt bond. Co2(CO)8? Ru3(CO)12 mixtures also bring about the copolymerization of propylene oxide with CO. The molar ratio of Ru to Co affects the yield, molecular weight, and structure of the produced copolymer. The catalysis is ascribed to the Ru? Co mixed‐metal cluster formed in the reaction mixture. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4530–4537, 2002 相似文献
214.
Regio- and stereo-controlled synthesis of boryl-substituted allylsilanes via transition metal-catalyzed additions of silylboranes to unsaturated organic compounds is described. Nickel-catalyzed reactions of (dimethylphenylsilyl)pinacolborane with 1,3-dienes, vinylcyclopropanes, and vinylcyclobutanes yielded 4-, 5-, and 6-boryl-substituted allylsilanes, respectively. Palladium-catalyzed addition of the silylborane to allenes took place at the more substituted C=C bond to yield 2-borylallylsilane selectively. The 2-borylallylsilanes served as useful allylation reagents in Lewis acid-mediated reactions with acetals and aldehydes. In addition to the simple allylation reactions, a cascade reaction to form the trans-9-boryl-1,2-benzooxadecalin skeleton and a cyclization reaction to form cyclic alkenylboranes were achieved by the use of 2-borylallylsilanes as key reagents. Reactions of methylenecyclopropanes were catalyzed by palladium and platinum catalysts. The reaction course, however, depended upon the substrate structure and the catalyst employed. For instance, cycloalkylidenecyclopropanes yielded 2-cycloalkylidene-3-boryl-1-silylpropanes selectively in the presence of a palladium catalyst, while 3-cycloalkylidene-3-boryl-1-silylpropanes were obtained selectively in the corresponding platinum-catalyzed reactions. 相似文献
215.
Yoshihiko Murata Toshikazu Ohtsuka Haruhisa Shirahama Takeshi Matsumoto 《Tetrahedron letters》1981,22(43):4313-4314
Sterpurene, a cyclohumulanoid obtained from silver-leaf disease fungus, was chemically derived from humulene via a route analogous to biosynthesis. 相似文献
216.
Hisao Nakata Yoshihiko Hoshino Naohito Takeda Akira Tatematsu 《Journal of mass spectrometry : JMS》1985,20(7):467-470
The mechanism of elimination of ROH (R = H or CH3) from the ammonium adduct ion, [M+NH4]+, of 1-adamantanol and its methyl ether is examined by using linked-scan metastable ion spectra and by measuring the dependence of the peak intensity ratio [M+NH4]+/[M+NH4? ROH]+ on ammonia pressure. For 1-adamantanol both SNi and SN1 reactions are suggested in metastable ion decomposition, while only the SN1 mechanism is operative in the ion source. For 1-adamantanol methyl ether the SN1 reaction predominates both in metastable ion decomposition and in the ion source reaction. 相似文献
217.
Ligand exchange reactions of alkylferrocenes with substituted benzenes were carried out. The steric effects of substituents on the reaction were almost equal irrespective of the site of the substituents, either on the cyclopentadienyl – or the benzene ring. For benzene ring substituents, the effect on the symmetrically substituted benzenes was greater than that on the unsymmetrically substituted benzenes. 相似文献
218.
Thiocarbonylation of a macrocyclic tetralactam gave a new macrocyclic tetrathiolactam. The chemical transformation enhances hydrogen-bonding ability of the NH protons in the cavity of the macrocycle, and provides strong affinity toward anions. The association properties of the polythiolactam with anions was examined, and molecular structures of the macrocycle and its Cl− complex were determined. 相似文献
219.
Yoshihiko Konno 《Annals of the Institute of Statistical Mathematics》1991,43(1):157-165
Let F
pxp
have the multivariate F-distribution with a scale matrix and degrees of freedom n
1and n
2. In this paper the problem of estimating eigenvalues of is considered. By constructing the improved orthogonally invariant estimators % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqefm0B1jxALjhiov2D% aebbfv3ySLgzGueE0jxyaibaiiYdd9qrFfea0dXdf9vqai-hEir8Ve% ea0de9qq-hbrpepeea0db9q8as0-LqLs-Jirpepeea0-as0Fb9pgea% 0lrP0xe9Fve9Fve9qapdbaqaaeGacaGaaiaabeqaamaabaabcaGcba% WaaCbiaeaacqqHuoaraSqabeaacaqGEbaaaOGaaiikaiaadAeacaGG% Paaaaa!402A!\[\mathop \Delta \limits^{\rm{\^}} (F)\] of , which are analogous to Haff-type estimators of a normal covariance matrix, new estimators of eigenvalues of are given. This is because the eigenvalues of % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqefm0B1jxALjhiov2D% aebbfv3ySLgzGueE0jxyaibaiiYdd9qrFfea0dXdf9vqai-hEir8Ve% ea0de9qq-hbrpepeea0db9q8as0-LqLs-Jirpepeea0-as0Fb9pgea% 0lrP0xe9Fve9Fve9qapdbaqaaeGacaGaaiaabeqaamaabaabcaGcba% WaaCbiaeaacqqHuoaraSqabeaacaqGEbaaaOGaaiikaiaadAeacaGG% Paaaaa!402A!\[\mathop \Delta \limits^{\rm{\^}} (F)\] are taken as estimates of the eigenvalues of . 相似文献
220.
Yoshihiko Imanaka Hideyuki Amada Fumiaki Kumasaka Naoki Awaji Akihito Kumamoto 《Journal of nanoparticle research》2016,18(4):102
Aerosol-type nanoparticle deposition (NPD) is a magical method to form a dense electroceramic film with a fine, nanoscale structure on a substrate surface by depositing ceramic particles through a nozzle at room temperature. This film has the potential to be applied to various electronic, environmental, and energy devices. However, the deposition mechanism and the nanostructure in the film are not understood sufficiently. This study aimed at investigating the crystal structure of an NPD as-deposited film, and compared the crystal structures of the NPD as-deposited film, annealed film, and the raw powders consisting of particles with diameters of 200 and 50 nm, respectively, using barium titanium oxide (BaTiO3). We found that the crystal in BaTiO3 with a disordered phase due to the Ba displacement within the BaTiO3 was responsible for the adhesion between the BaTiO3 crystalline particles having a diameter of approximately 10 nm, as well as with the substrate. 相似文献