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101.
Hirohara S Obata M Saito A Ogata S Ohtsuki C Higashida S Ogura S Okura I Sugai Y Mikata Y Tanihara M Yano S 《Photochemistry and photobiology》2004,80(2):301-308
Thirty-two glycoconjugated porphyrins were synthesized by a modification of Lindsey method in the presence of Zn(OAc)(2).2H(2)O as a template. The Zn(2+) ion template strategy improved the yield about three-fold in the case of meta-substituted tetraphenylporphyrins. In addition, free-base porphyrins were obtained almost quantitatively by demetalation with 4 M HCl. Sixteen deacetylated glycoconjugated porphyrins were tested as candidate photodynamic therapy (PDT) drugs using HeLa cells. Most of the deacetylated glycoconjugated porphyrins showed higher cellular uptake than tetraphenylporphyrin tetrasulfonic acid (TPPS), and 5,10,15,20-tetrakis[4-(beta-D-arabinopyranosyloxy)phenyl]porphyrin (p-5d) in particular showed 18.5-fold higher uptake than TPPS. The photocytotoxicity of 5,10,15,20-tetrakis[4-(beta-D-glucopyranosyloxy)phenyl]porphyrin (p-5a), p-5d and TPPS was examined with HeLa cells, using a light dose of 16 J/cm(2). These photosensitizers had no cytotoxicity in the dark, but their photocytotoxicity increased in the order of TPPS < p-5a < p-5d. These results suggest p-5d is a good candidate for a PDT drug. 相似文献
102.
T. Ishihara K. Nishida H. Nishiguchi Y. Takita K. Chaki 《Research on Chemical Intermediates》2006,32(3):253-262
A new reforming process was studied using Ni/SiO2 with a hydrogen-permeating membrane reactor. Nickel catalyst supported on SiO2 is highly active for CH4-H2O-O2 reaction in membrane reactor and the reaction close to CH4 + 0.35O2 + 1.3H2O → CO2 + 3.3H2 proceeds at 873 K. Since the selectivity to carbon and CO2 increased and decreased with decreasing contact time respectively, it is considered that the reaction was started by decomposition
of CH4 followed by oxidation of C and water shift reaction. Therefore, the reaction mechanism was different from so-called autothermal
reforming (ATR) reaction. 相似文献
103.
Dehydrogenation of benzyl-type alcohols and hydroaromatic compounds by 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tetrachloro-p-benzoquinone were examined, and the hydrogen transfer from 1-phenyl-1-propanol to DDQ was investigated in detail. The yield of the propiophenone increased when solvents which would be expected to increase the concentration of the charge transfer complex between the alcohol and DDQ were used. Initial rates of the reaction in dioxane were proportional to the concentration of the hydrogen donor and that of the hydrogen acceptor. In the dehydrogenation of several para- or meta-substituted 1-phenyl-1-propanols at 60°, ?3.30 was obtained as a value of reaction constant. Relative rates of the reaction of PhCH(OH)Et, PhCH(OD)Et, PhCD(OH)Et, and PhCD(OD)Et were 8.9,9.1,1.0 and 1, respectively. This result suggests that the transfer of the H atom attached to the α-carbon of the alcohol is the rate-determining step. This and some other results support a two-step ionic mechanism for the dehydrogenation of alcohols. 相似文献
104.
Homolytic aromatic substitution and hydrogen abstraction reactions with cyclopropyl radical were carried out to determine the reactivity and ionic character of cyclopropyl radical by examination of the orientation effect, partial rate factor and influence of substituents. By thermal decomposition of biscyclopropaneformyl peroxide in a series of substituted benzenes, the corresponding cyclopropylated benzene derivatives (the mixture of ortho, meta and para isomers) were obtained in moderate yield. In view of the orientation effect and the partial rate factor, the cyclopropyl radical seems to be fairly free from polar effect, and to resemble the phenyl radical more than the common alkyl radical although the cyclopropyl radical has a slightly higher reactivity than the phenyl radical. The relative reactivity of the 2-phenylcyclopropyl radical in the hydrogen abstraction reaction toward the benzylic position of ring-substituted toluenes gave good Hammett's correlation with the slope of + 0·20 suggesting little ionic character in the transition state. This result was in good agreement with the conclusion obtained from homolytic aromatic substitution reaction and with the chemical reactivity to be expected from the non-planar nearly sp2-hybridized conformation of the cyclopropyl radical. 相似文献
105.
A pair of copper(II) complexes 1 and 2 exhibit an enantiomeric chiral center at the oxygen atom that coordinates to the metal center. The configurations of the oxygen atom chirality and the chelate ring conformation are simply controlled by protected/free hydroxyl groups of the sugar moiety, yielding mirror image CD spectra. In this system, repulsive and attractive forces are used to regulate chirality on the copper-coordinated oxygen atom both in the solid state and in solution. 相似文献
106.
Shigenobu Hayashi 《Journal of solid state chemistry》2004,177(3):824-833
Sites and dynamics of deuterium in VD0.50 as well as in VD0.40 and VD0.57 have been studied by means of X-ray diffraction, differential scanning calorimetry and 2H NMR. VD0.40 consists of the body-centered-cubic (bcc) αD and body-centered-tetragonal (bct) βD phases at room temperature and only the octahedral (O) sites are occupied in the βD phase. On the other hand, in VD0.50, consisting of the bctβD phase at room temperature, the O site is dominantly occupied with a small occupancy of the tetrahedral (T) sites in the βD phase. VD0.57 is composed of the bccα′D (a high-deuterium-concentration phase of the αD phase) and bctβD phases at room temperature, and the occupancy of the T sites is observed. The mean activation energy (ED) of the deuterium diffusion is much larger for the O sites than for the T sites, and the diffusion is also much slower in the O sites. The mean ED values for the O sites are almost the same in the βD phase of VD0.40 and VD0.50, although the distribution of the mean residence time is much larger in VD0.50 than in VD0.40. 相似文献
107.
Shigenobu Hayashi Kikuko Hayamizu Osamu Yamamoto 《Journal of solid state chemistry》1983,46(3):306-312
The structure of the TiVH system is studied by X-ray diffraction and 1H and 51V NMR measurements. It is shown that the solid solution of TiV is separated into a few phases by hydrogenation. They are α-TiVH, β-TiVH, γ-TiVH, and γ-TiH phases, which are assumed to have their origins either in TiHx or in VHx. The concentration of each phase can be estimated by NMR, which is dependent on the composition of the system. The phase separation caused by hydrogenation is due to the large stability of the γ-TiH phase. 相似文献
108.
Storr T Fisher CL Mikata Y Yano S Adam MJ Orvig C 《Dalton transactions (Cambridge, England : 2003)》2005,(4):654-655
The synthesis and metal complexation of a glucosamine-appended 2,2'-dipicolylamine ligand to the tricarbonyls of 99mTc and 186Re is described; the ligand was found to bind in a tridentate fashion with the glucosamine function remaining pendant, and the 99mTc complex was found to exhibit exceptional stability towards in vitro ligand exchange experiments. 相似文献
109.
Hiroyasu Nishiguchi Shuji Kimura Tatsumi Ishihara Yusaku Takita 《Research on Chemical Intermediates》1998,24(4):391-399
Cu ion-exchanged SAPO-34 which is a highly active catalyst for selective reduction of NO with C3H6, was synthesized and the Cu ion was characterized in the SAPO-34 by ESR, XPS, IR, and XAFS. ESR study indicated that two
kinds of Cu(II) with different environments exist in SAPO-34. The Cu(II) species disappeared immediately by C3H6 treatment and recovered by oxygen treatment. XAFS study indicated that most of the Cu(II) was reduced to Cu(I) under the
presence of C3H6.
These studies revealed that a selective NO reduction by C3H6 over SAPO-34 should proceed by the redox reaction of a copper ion between Cu(I) and Cu(II). 相似文献
110.
Itoh S Takada N Haranou S Ando T Komatsu M Ohshiro Y Fukuzumi S 《The Journal of organic chemistry》1996,61(25):8967-8974
The reactions of a TTQ model compound [1, 3-methyl-4-(3'-methylindol-2'-yl)indole-6,7-dione] with several amines have been investigated in organic media to obtain mechanistic information on the action of quinoprotein methylamine and aromatic amine dehydrogenases. It has been found that compound 1 acts as an efficient catalyst for the autorecycling oxidation of benzylamine by molecular oxygen in CH(3)OH. In order to evaluate the oxidation mechanism of amines by 1, the product analyses and kinetic studies have been carried out under anaerobic conditions. In the first stage of the reaction of 1 with amines, 1 is converted into an iminoquinone-type adduct (so-called substrateimine), which was isolated and characterized by using cyclopropylamine as a substrate. The observed NOE of the isolated product indicates clearly that the addition position of the amine is C-6 of the quinone. The molecular orbital calculations suggest that the thermodynamic stability of the carbinolamine intermediate is a major factor to determine such regioselectivity; the C-6 carbinolamine is more stable than the C-7 counterpart by 2.9 kcal/mol. The reactivity of several primary amines and the electronic effect of the p-substituents of benzylamine derivatives in the iminoquinone formation suggest that the addition step of the amine to the quinone is rate-determining. When amines having an acidic alpha-proton such as benzylamine derivatives are employed as substrates, formation of the iminoquinone adduct was followed by rearrangement to the productimine. The kinetic analysis has revealed that this rearrangement consists of noncatalyzed and general base-catalyzed processes. Large kinetic isotope effects of 7.8 and 9.2 were observed for both the noncatalyzed and general base-catalyzed processes, respectively, since these steps involve a proton abstraction from the alpha-position of the substrate. In the reaction with benzhydrylamine, the product imine was isolated quantitatively and well characterized by several spectroscopic data. In the case of benzylamine, the product imine is further converted into the aminophenol derivative by the imine exchange reaction with excess benzylamine. These results indicate clearly that the amine oxidation by compound 1 proceeds via a transamination mechanism as suggested for the enzymatic oxidation of amines by TTQ cofactor. 相似文献