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641.
642.
Kenji Mori Masayuki Sakakibara Yoshitaka Ichikawa Hiraki Ueda Katsuhide Okada Takeaki Umemura Goro Yabuta Shigefumi Kuwahara Michitada Kondo Masao Minobe Akemi Sogabe 《Tetrahedron》1982,38(14):2099-2109
(22S, 23S)-Homobrassinolide (2α, 3α, 22S, 23S-tetrahydroxy-24S-etyl-B-homo-7-oxa-5α-cholestan-6-one) and brassinolide (2α, 3α 22R, 23R-tetrahydroxy-24S-methyl-B-homo-7-oxa-5α-cholestan-6-one) were synthesized from stigmasterol and shown to promote plant growth. 相似文献
643.
Lazarin AM Landers R Kholin YV Gushikem Y 《Journal of colloid and interface science》2002,254(1):31-38
This work describes the preparation and characterization of a cellulose acetate fiber coated with Al(2)O(3), resulting in the organic-inorganic hybrid Cel/Al(2)O(3). Furthermore, the hybrid was modified by attaching organofunctional groups by reaction with the precursor reagents (RO)(3)Si(CH(2))(3)L (L=NH(2), NH(CH(2))(2)NH(2), NH(CH(2))(2)NH(CH(2))(2)NH(2), and N(2)C(3)H(3) (imidazole)), resulting in Cel/Al(2)O(3)/Si(CH(2))(3)NH(2) (1), Cel/Al(2)O(3)/Si(CH(2))(3)NH(CH(2))(2)NH(2) (2), Cel/Al(2)O(3)/Si(CH(2))(3)NH(CH(2))(2)NH(CH(2))(2)NH(2) (3), and Cel/Al(2)O(3)/Si(CH(2))(3)N(2)C(3)H(3) (4). The amounts of attached organofunctional groups were (in mmol per gram of the material) 1=1.90, 2=1.89, 3=1.66, and 4=1.35. The isotherms of adsorption of FeCl(3), CuCl(2), and ZnCl(2) by Cel/Al(2)O(3)/Si(CH(2))(3)L from ethanol solutions were obtained at 298 K. Accurate estimates of the specific sorption capacities and the heteregeneous stability constants of the immobilized metal complexes were determined with the aid of several computational procedures. It is shown that the sorptional capacities are much less than the concentrations of the attached organofunctional groups. As all sorption isotherms are fitted properly with the Langmuir isotherm equation, the effects of the energetic heterogeneity and the lateral interactions do not affect the chemisorption equilibria. The heterogeneous stability constants of the immobilized complexes are fairly high, which provides efficient removal of the metal ions from solutions by the hybrid materials. 相似文献
644.
Nishida H Miyazaki Y Mukaihira T Shimada H Suzuki K Saitoh F Mizuno M Matsusue T Okamoto A Hosaka Y Matsumoto M Ohnishi S Mochizuki H 《Chemical & pharmaceutical bulletin》2004,52(4):459-462
Compounds containing an ethylenediamine structure in place of the piperazine ring of M55113 (1) and M55551 (2) were synthesized to investigate the effects of a piperazine moiety and evaluated for activity as factor Xa (FXa) inhibitors. Most such compounds, however, exhibited lower activity (1/10-1/100) than that of M55113 and M55551 as FXa inhibitors. 相似文献
645.
Tadashi Ii Yoko Ohashi Yuji Matsuzaki Tomoya Ogawa Yoshitaka Nagai 《Journal of mass spectrometry : JMS》1993,28(11):1340-1344
The structural characterization of large synthetic oligosaccharides and related glycoconjugates performed by the use of electrospray ionization mass spectrometry (ESIMS) is described. The largest molecules described here are unprotected and protected pentaantennary pentacosasaccharides 2 and 5 with average molecular masses of 4441 and 9416, respectively. The straight-chain neutral ceramide decasaccharide (d18:1/c24:0) 6 and the disialoganglioside GD2 (d18:1/c24:0) 7 were also successfully analyzed by ESIMS. In addition to exact mass determination, collision-induced dissociation (CID) spectrometry of these compounds provided saccharide chain sequence information. 相似文献
646.
Jianhua Liu Yoshitaka Masuda Eiichi Sekido Shin-Ichi Wakida Kazuo Hiiro 《Analytica chimica acta》1989
An ion-selective coated-wire/field-effect transistor electrode responding to dihydrogenphosphate is described. The device consists of a coated-platinum wire electrode connected to the gate of a conventional field-effect transistor. Cobalt phthalocyanine is used as ion-exchange electroactive substance and poly(vinyl chloride) as the membrane matrix. The characteristics of the device are investigated and its response is studied by two methods, the linear dependence of the square root of the drain current in the saturated region on the logarithm of ion activity for sodium dihydrogenphosphate, and the dependence of the gate-source potential on the logarithm of ion activity of the same ion. A linear response is obtained in the range of ion activity 10?5-10?1 mol dm?3 and the response slope is 45 mV per decade change of H2PO4? ion activity; the selectivity coefficients are discussed. 相似文献
647.
Yamaguchi Y Kashiwabara T Ogata K Miura Y Nakamura Y Kobayashi K Ito T 《Chemical communications (Cambridge, England)》2004,(19):2160-2161
The reaction of an imidazolium salt with LiBEt(3)H afforded triethylborane adduct of imidazol-2-ylidene, which can act as a carbene precursor for the synthesis of a transition metal complex as well as a main group element complex. 相似文献
648.
Zenjiro Osawa Takao Kimura Yoshitaka Ogiwara Noriyuki Matsubayashi 《Journal of polymer science. Part A, Polymer chemistry》1971,9(7):2039-2049
Polymerization of methyl methacrylate with Grignard reagent in toluene–dioxane mixed solvent was carried out under ultrasonic irradiation. The effects of ultrasonic irradiation and the order of catalyst addition on Grignard reagent and the microstructure in the reacting sites were examined on the basis of the stereoregularity of polymers and oligomers produced. The formation of oligomers was also discussed on the basis of the consumption of initiator. The stereoregularity of the polymers in series A (no ripening of catalyst with solvent) is higher than that in series B (ripening of catalyst with solvent). The effect of ultrasonic irradiation on the stereoregularity was completely reversed in series A and B; it increased in the former and decreased in the latter with ultrasonic irradiation. Similar results were obtained for the stereoregularity of the oligomers, but the stereoregularity of the oligomers was lower than that of polymers. 相似文献
649.
Hiroshi Horikawa Takashi Nishitani Tameo Iwasaki Yoshitaka Mushika Ichizo Inoue Muneji Miyoshi 《Tetrahedron letters》1980,21(42):4101-4104
The Diels-Alder reaction of N-acyl-α,β-dehydroalanine esters with cyclopentadiene afforded a mixture of the stereoisomers of acylaminonorbornene-2-carboxylic acid esters in good yields. 相似文献