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41.
Sixteen dioxime compounds, including six new compounds, were synthesized and their reactions with nickel, cobalt, iron(II, III) and copper ions were examined. The nickel chelates of the glyoxime derivatives show hardly any absorption in the visible region, and are therefore unsuitable as color reagents. The nickel chelates of the benzildioxime derivatives can be extracted into organic solvents and provide a selective color reaction, so that useful extraction-spectrophotometric methods are possible. The metal complexes of quinonedioximes are extracted into some organic solvents, and the complexes have relatively large molar absorptivities in the visible region, but the reagents are not selective. However, the molar absorptivity of the ternary complex, Ni2+-reagent-zephiramine, with 1,2-naphthoquinonedioxime-4-sulfonic acid was 2.03·104 at 480 nm, and that of the nickel complex of 9,10-phenanthrenequinonedioxime was 2.49·104at 456 nm. The compositions of the nickel-dioxime complexes were examined spectrophotometrically. 相似文献
42.
Sakamoto M Ohba A Kuriyama J Maruo K Ueno S Sato K 《Colloids and surfaces. B, Biointerfaces》2004,37(1-2):27-33
We examined the crystallization of palm mid fraction (PMF) in oil-in-water (O/W) emulsion, after adding polyglycerol fatty acid esters (PGFEs). We employed ultrasonic velocity measurements and DSC techniques, with special emphases on the influences of fatty acid moiety and esterification of PGFE. Twelve types of PGFEs were examined as additives. PGFEs have a large hydrophilic moiety composed of 10 glycerol molecules to which palmitic, stearic and behenic acids were esterified as the fatty acid moiety with different degrees of esterification. Crystallization temperature (T(c)) of PMF remarkably increased with increasing concentrations of the PGFEs as the chain length of the fatty acid moiety increased, and the PGFE became more hydrophobic in accordance with increasing degree of esterification. We observed that the heterogeneous nucleation of PMF in the O/W emulsion was activated at the oil-water interface, where the template effect of very hydrophobic long saturated fatty acid chains of the PGFE might play the main role of heterogeneous nucleation. 相似文献
43.
Ozeki H Nomoto A Ogawa K Kobuke Y Murakami M Hosoda K Ohtani M Nakashima S Miyasaka H Okada T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(24):6393-6401
We synthesized special-pair/electron-acceptor systems consisting of a complementary slipped cofacial dimer of imidazolyl-substituted zinc porphyrin, bearing pyromellitdiimide as the electron acceptor. In the case of the dimer, the first and second oxidation potentials were split into a total of four peaks in the differential pulse voltammetry measurement. Furthermore, the shift values of the first oxidation potentials obtained by changing the solvent polarity for the dimer were almost half of those observed for the monomer. These results indicate that the radical cation is delocalized over the whole pi system of the dimer. Time-resolved transient absorption measurements revealed that, relative to the corresponding monomer, the dimer accelerated the charge separation rate, but decelerated the charge recombination rate. The smaller reorganization energy of the slipped cofacial dimer relative to that of the monomeric system demonstrates the significance of the special-pair arrangement for efficient charge separation in photosynthesis. 相似文献
44.
Makoto Masuda Satoru Takamatu Noriyuki Nishimura Saburo Komatsubara Tetsuya Tosa 《Applied biochemistry and biotechnology》1993,43(3):189-197
Serratia marcescens SP511 was previously reported to be anl-proline-producing strain that harbors a recombinant plasmid carrying the mutant type of the proline operon. This strain produced 65 g/L ofl-proline in a medium containing 22% sucrose and urea after 5 d of incubation under the conventional culture conditions. We searched for more suitable culture conditions for more abundantl-proline production by SP511. To improve the supply of a nitrogen source to cells, ammonium was used instead of urea and fed to a culture under control of the pH of the medium. The concentrations of MgSO4 and K2HPO4 were increased, and in addition, sucrose was continuously added to the culture at a final concentration of 32%. Under these conditions, the cell amount was increased twofold over that under the previous conditions andl-proline production reached a maximum of more than 100 g/L after 4 d of incubation. 相似文献
45.
Synthesis of 12-deoxyroyleanone, cryptoquinone, 11,14-dihydroxy-8,11,13-abietatrien-7-one, and related derivatives from dehydroabietic acid 总被引:1,自引:0,他引:1
Yoh-ichi Matsushita Yoshihisa Iwakiri Satoru Yoshida Kazuhiro Sugamoto Takanao Matsui 《Tetrahedron letters》2005,46(21):3629-3632
Naturally occurring abietane quinones and hydroquinone, namely, 12-deoxyroyleanone (1a), cryptoquinone (4a), and 11,14-dihydroxyabieta-8,11,13-trien-7-one (5a), together with the epimers of tryptoquinones D (2) and F (3), were first synthesized from dehydroabietic acid (6). 相似文献
46.
A simple aliphatic dipeptide, l-leucyl-l-alanine (Leu-Ala), includes several alkyl methyl sulfoxides enantioselectively to form inclusion crystals. From single-crystal X-ray analyses of three inclusion compounds of dimethyl sulfoxide (DMSO), isobutyl methyl sulfoxide, and benzyl methyl sulfoxide, it was elucidated that Leu-Ala molecules self-assemble to form layer structures and the sulfoxides are included via hydrogen bonding in a cavity between these layers. The inclusion cavity has methyl group and isobutyl group at its each side, and the guest sulfoxide is placed in such a manner that its methyl group faces toward the methyl of the Leu-Ala cavity. When the alkyl group of the sulfoxide is comparably large, it is located in the residual space of the cavity to attain effective crystal packing. Thus, the sulfoxides having a comparably large group such as isobutyl, butyl, and benzyl are included with a high (R)-enantioselectivity in Leu-Ala crystals. 相似文献
47.
S. Watanabe N. S. Ishioka T. Sekine A. Osa M. Koizumi H. Shimomura K. Yoshikawa H. Muramatsu 《Journal of Radioanalytical and Nuclear Chemistry》2003,255(3):495-498
Ion implantation was applied to the production of endohedral 133Xe-fullerene. Using an isotope separator, 133Xe ions were implanted into a fullerene target of C60 and C70 produced by vacuum evaporation on a Ni backing. An HPLC analysis following dissolution of the fullerene targets in o-dichlorobenzene corroborated the formation of 133Xe@C60 and 133Xe@C70, showing a strong correlation between C60/C70 and 133Xe. The observed tailing following 133Xe peaks in the elution curves suggests a possibility of the isolation of endohedral 133Xe-fullerene from empty fullerene. 相似文献
48.
α-Fluorinated esters were effectively prepared by the Baeyer-Villiger oxidation of α-fluorinated ketones with m-chloroperbenzoic acid (m-CPBA) under mild conditions. The yield of the esters was influenced by the choice of solvent, base, and substituent on the aryl group of the ketones. 4-Methoxyphenyl substituted fluoroketones were oxidized almost quantitatively with m-CPBA within 10 min to 12 h at room temperature using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a cosolvent with CH2Cl2 (1:1, v/v) and aqueous buffer (KH2PO4-NaOH, pH 7.6) as an additive base. The oxidation reaction rates of α-fluorinated ketones were higher than those of the corresponding non-fluorinated ketones. The fluorine atom at α-position of fluoromethyl aryl ketones enhanced the reactivity in the Baeyer-Villiger oxidation. 相似文献
49.
A new non-C2-symmetrical antimony-phosphorous ligand, (±)-2-diphenyl-phosphano-2′-di(p-tolyl)stibano-1,1′-binaphthyl (BINAPSb) 3, has been prepared from 2-bromo-2′-diphenylphosphano-1,1′-naphthyl 4 via its borane complex 6, and could be resolved by the separation of a mixture of the diastereomeric palladium complexes 8A and 8B derived from the reaction of (±)-3 with optically active palladium reagent (S)-7. The enantiomerically pure BINAPSb 3 has proved to be highly effective in the palladium-catalyzed asymmetric hydrosilylation of styrene as a chiral auxiliary. 相似文献
50.
Kamoda S Nomura C Kinoshita M Nishiura S Ishikawa R Kakehi K Kawasaki N Hayakawa T 《Journal of chromatography. A》2004,1050(2):211-216
Carbohydrate chains in glycoprotein pharmaceuticals have important roles for the expression of their biological activities. Therefore, development of an assessment method for the carbohydrate chains is an important parameter for quality control of glycoprotein pharmaceuticals such as newly developed therapeutic antibodies. In this report, we applied capillary electrophoresis with laser-induced fluorescence detection to the analysis of carbohydrate chains after releasing with glycoamidase followed by derivatization with 3-aminobenzoic acid. We found that four major oligosaccharides present in antibody pharmaceuticals were successfully separated with good resolution. The present method showed good precision in both migration times and relative peak areas, and gave comparable accuracy with that using a derivatization method with 8-aminopyrene-1,3,6-trisulfonate. 相似文献