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61.
Nobuko WatanabeYasuhiro Nagashima Takahiro YamazakiMasakatsu Matsumoto 《Tetrahedron》2003,59(26):4811-4819
Tetrabutylammonium fluoride induces the decomposition of 1-tert-butyl-4,4-dimethyl-5-(3-siloxyphenyl)-2,6,7-trioxabicyclo[3.2.0]heptane (4a) in DMSO to form an oxyanion of aromatic ketone (14a) as an emitter with high singlet-chemiexcitation yield comparable with that for a chemically initiated electron exchange luminescence (CIEEL) active dioxetane producing an oxyanion of aromatic ester as an emitter. A 7-siloxynaphthalen-2-yl analog (4b) was found on similar treatment to emit light with the maximum wavelength the longest among CIEEL-active dioxetanes hitherto known. 相似文献
62.
63.
The title reaction was carried out with the help of the transient response method over MgO. It was concluded that no catalyst reduction occurred over this catalyst and the reaction proceeded through the reaction between adsorbed nitrous oxide and adsorbed carbon monoxide without participation of MgO oxygen.
MgO. , - MgO.相似文献
64.
A highly efficient copper-catalyzed coupling reaction of aryl iodides and thiobenzoic acid, using 10 mol % of copper iodide, 20 mol % of 1,10-phenanthroline, and iPr2NEt in toluene, was developed. This methodology is applicable to a variety of aryl iodides. 相似文献
65.
Fukuyama T Yamaura R Higashibeppu Y Okamura T Ryu I Kondo T Mitsudo TA 《Organic letters》2005,7(26):5781-5783
[reaction: see text] Catalytic [2 + 2 + 1 + 1] cocyclization reaction of an alkyne, an alkene, and two molecules of carbon monoxide, leading to functionalized hydroquinones, was studied. Using [Cp*RuCl2]2 as a catalyst, we found that a variety of electron-deficient alkenes, such as alpha,beta-unsaturated ketones, esters, amides, and nitriles, can be employed as an alkene coupling partner to give the corresponding hydroquinones. 相似文献
66.
Yoshiyuki Tanaka Makoto Arakawa Yohei Yamaguchi Chieko Hori Masahiro Ueno Takeyuki Tanaka Tatsushi Imahori Yoshinori Kondo 《化学:亚洲杂志》2006,1(4):581-585
A metal‐free acetylide was observed by using NMR spectroscopy. Metal‐free acetylides are closely related to reactive intermediates (carbanions) in solution; therefore, they have been regarded as unobservable species. However, we generated this highly reactive and unstable species through the deprotonation of phenylacetylene by using the strong nonmetallic phosphazene base tBu‐P4. In the presence of tBu‐P4, the J coupling between the ethynyl carbon and hydrogen nuclei (1JC,H) of phenylacetylene disappeared; this indicates the deprotonation of the alkyne terminal. Furthermore, a large low‐field shift (approximately 90 ppm) of the alkyne carbon resonance was observed. We concluded that we have observed a metal‐free carbanion with a formal charge on an sp‐hybridized carbon atom for the first time. 相似文献
67.
Determination of protein spots separated by two-dimensional polyacrylamide gel electrophoresis 总被引:1,自引:0,他引:1
A simple method for quantitating proteins in the spots on two-dimensional polyacrylamide gel electropherograms is described. The system consists in three steps: (1) O'Farrell's two-dimensional gel electrophoresis of the proteins to be analysed; (2) staining of the gels with Coomassie brilliant blue; and (3) determination of the area and integrated density of the stained spots by the Joyce Loebl Magiscan-1 image analysis system. The method can be used for the determination of proteins in the range 0.5-100 micrograms/cm2; the amount of protein involved in most spots detected by the staining method actually falls within this range. As the minimum spot diameter that can easily be handled by the method is about 2 mm, as much as 30 ng of protein in such a spot can be determined. The method can also be applied to autoradiograms. 相似文献
68.
[reaction: see text] 2-Methylfurans were prepared by an effective cyclization of 1-alkyn-5-ones in the presence of mercuric triflate as the catalyst under very mild reaction conditions with high catalytic turnover up to 100 times. Benzene, toluene, or dichloromethane was the solvent of choice. 相似文献
69.
Ishizaka T Miyanaga Y Mukai J Asaka K Nakai Y Tsuji E Uchida T 《Chemical & pharmaceutical bulletin》2004,52(8):943-948
The purpose of this study was to evaluate the bitterness of 18 different antibiotic and antiviral drug formulations, widely used to treat infectious diseases in children and infants, in human gustatory sensation tests and using an artificial taste sensor. Seven of the formulations were found to have a bitterness intensity exceeding 1.0 in gustatory sensation tests (evaluated against quinine as a standard) and were therefore assumed to have an unpleasant taste to children. The bitterness intensity scores of the medicines were examined using suspensions in water or an acidic sports drink. In the case of three macrolide antibiotic formulations containing erythromycin (ERYTHROCIN dry syrup), clarithromycin (CLARITH dry syrup for pediatric), and azithromycin (ZITHROMAC fine granules for pediatric use), the bitterness intensities of suspensions in acidic sports drinks were dramatically enhanced compared with the corresponding scores of suspensions in water. This enhancement could be predicted using the taste sensor. On the other hand, a reduction of bitterness intensity was observed for an acidic sports drink suspension of an amantadine product (SYMMETREL fine granules) compared with an aqueous suspension. This reduction in bitterness could also be predicted using the taste sensor output value. Thus, the taste sensor could predict whether or not suspension in an acidic sports drink would enhance or reduce the bitterness intensity of pediatric drug formulations, compared with suspensions in water. 相似文献
70.
From the standpoint of protein dynamics and metalloprotein design, it is interesting to create an artificial protein which induces structural change and regulates its function by metal-ion binding. We engineered a novel protein, "Antennafinger (Ant-F)", whose structure and function can be controlled with Zn(II), by introducing the consensus sequence of a Cys(2)His(2)-type zinc finger protein into a non-metalloprotein scaffold, an Antennapedia homeodomain mutant (Ant-wt), selected using a motif-searching system. The circular dichroism studies demonstrate that Ant-F has secondary structures similar to Ant-wt and also changes its conformation due to Zn(II)-binding. The optical absorption spectra of the Co(II) complexes of Ant-F and its derivative proteins suggest that the geometry of the metal center of holo-Ant-F is tetrahedral and that the mutated Cys(2)His(2) residues are involved in the complex formation. In addition, the gel mobility shift assay reveals that the DNA binding activity of Ant-F can be regulated through Zn(II)-induced structural alteration. These results provide valuable information about the dynamic properties of proteins and a novel concept for metalloprotein design. 相似文献