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51.
Tokuyama R Takahashi Y Tomita Y Suzuki T Yoshida T Iwasaki N Kado N Okezaki E Nagata O 《Chemical & pharmaceutical bulletin》2001,49(4):347-352
A structure-activity relationship (SAR) study on 5-substituted oxazolidinones as an antibacterial agent is described. The oxazolidinones, of which 5-acetylaminomethyl moiety was converted into other functions, were prepared and evaluated for antibacterial activity. Elongation of the methylene chain (8) and conversion of the acetamido moiety into guanidino moiety (12) decreased the antibacterial activity. The replacement of carbonyl oxygen (=O) by thiocarbonyl sulfur (=S) enhanced in vitro antibacterial activity. Especially, compound 16, which had the 5-thiourea group, showed 4-8 stronger in vitro activity than linezolid. Our SAR study revealed that the antibacterial activity was greatly affected by the conversion of 5-substituent. 相似文献
52.
A. Fukumi I. Endo T. Horiguchi Y. Ishida T. Kondo T. Kuwamoto H. Matsuzaki T. Nakamura T. Takahashi 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1997,42(4):243-249
Systematic study of hyperfine structures, Zeeman and Stark effects in Sm I is performed for the lowest 7G1-6 levels belonging to the configuration 4f 66s6p by atomic-beam laser spectroscopy with fluorescence detection. The hyperfine coupling constants of 7G2-6 levels are determined. From the Zeeman splittings for the 4f 66s 2 7F2-6 ? 4f 66s6p 7G2-6 transitions, g-values are determined for the 7G2.6 levels and the precision is improved by several orders of magnitude. From the Stark splittings for the 7F0-3 ? 7G1-3 transitions, tensor polarizabilities α 2(J) are determined for the upper 7G1-3 levels. Particularly for the 7G1 level (15 650.55 cm?1) which has close-lying opposite-parity level, the isotope dependence of α 2(J) is clearly observed for the first time. 相似文献
53.
Takako Takahashi 《Journal of polymer science. Part A, Polymer chemistry》1968,6(12):3327-3331
Vinylcyclopropane derivatives, 1-chloro- and 1-bromo-2-vinylcyclopropane, have respectively two stereoisomers, and radical polymerizations of both isomers gave 1,5-type polymers. On the other hand, only the cis isomers gave a polymer which had mainly 1,2-type structural units in cationic polymerizations with Lewis acids. The difference between the cationic polymerizabilities of the cis and trans isomers is interpreted in terms of steric conformation of monomers. 相似文献
54.
Submicron-size monodisperse polystyrene/polyglutaraldehyde (PS/PGLA) composite particles having aldehyde groups at the surfaces were produced by the seeded aldol condensation polymerization of glutaraldehyde at various temperatures of 040°C. Since a part of aldehyde groups was consumed by the Cannizzaro reaction (hemiacetal formation) as a intermolecular reaction of PGLA, the amount of aldehyde groups on PS/PGLA composite particles was varied by the competition between the aldol condensation reaction and the Cannizzaro reaction at the various temperatures.Part CXXXIX of the series Studies on Suspension and Emulsion 相似文献
55.
Hiroki Nakamura Jiro Tanaka Nobuaki Nakashima Keitaro Yoshihara 《Chemical physics letters》1981,77(2):419-421
The photoionization of 8-anilino-1-naphthalenesulfonate in polar solvents occurs through a biphotonic process, as proved by nanosecond flash photolysis. A transient absorption of a charge transfer to solvent (CTTS) state is found with ≈10 ns life-time. The state is shown to be an intermediate of the photoionization process. 相似文献
56.
Kô Kaneko Mikako Tanaka Kimiaki Haruki Nobuaki Naruse Hiroshi Mitsuhashi 《Tetrahedron letters》1979,20(39):3737-3740
The 13C-NMR spectra of seven cavanine alkaloids isolated from Veratrum and Fritillaria plants were measured and their signals were assigned, and these results were applicated for structure elucidation of two new cevanine alkaloids, baimonidine and isoverticine, isolated from mature Fritillaria verticillata. 相似文献
57.
N. Takahashi T. Shimoda Y. Fujita T. Itahashi H. Miyatake 《Zeitschrift für Physik B Condensed Matter》1995,98(3):347-351
Short-lived ions12B (beta-radioactive, T1/2=20.3 ms) sustaining nuclear spin polarization were introduced into superfluid helium at 1.7 K. It was found that the12B ions were transported as charged entities under a static electric field and that the nuclear polarization was maintained throughout the lifetime of12B nuclei. Polarization of12B was determined through beta-NMR method. Snowball, a singly charged microcluster of helium atoms formed around an impurity ion, is responsible for the behaviour and thus constitutes a suitable environment for preserving nuclear polarization of the core ions12B. In a separate experiment snowballs were produced by implanting8Li (T1/2=830 ms) into liquid helium and detected by means of alpha particles from the core ions to guarantee that the snowballs survive longer than the lifetime of12B. 相似文献
58.
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60.
Koiso T Yamamoto K Hata Y Takahashi Y Kita E Ohshima K Okamura FP 《J Phys Condens Matter》1996,8(38):7059-7065
A structural study of [Formula: see text], grown from aqueous solution, was performed using anomalous x-ray scattering near the Cs K absorption edge to determine an absolute configuration of constituent atoms. The sense of the helical structure of the [Formula: see text] chain was found to be predominantly right-handed through a comparison of observed Bragg Bijvoet ratios with calculated ones. Assuming that [Formula: see text] consists of the two domains (i.e. right- and left-handed helices), we estimate that the volume fraction for the right-handed helix is [Formula: see text]. 相似文献