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411.
Yoshikazu Isowa Muneki Ohmori Tetsuya Ichikawa Kaoru Mori Yuji Nonaka Kei-ichi Kihara Kiyotaka Oyama Heijiro Satoh Shigeaki Nishimura 《Tetrahedron letters》1979,20(28):2611-2612
The title reactions occur with concurrent peptide synthesis and optical resolutions of racemic substrates. With this method, Z-L-Asp-L-Phe-OME, the precursor to the synthetic sweetner, could be obtained in high yield. 相似文献
412.
Takako Yamaguchi Mayumi Inoue Kanako Miyachi Hiroshi Tominaga Yoshikazu Fujita 《Analytical sciences》2004,20(2):387-389
A simple and highly sensitive spectrophotometric method for the determination of glucosamine and its analogous amino sugars was established based on fading of the palladium(II)-o-hydroxyhydroquinonephthalein-hexadecyltrimethylammonium complex. In the determination of glucosamine, Beer's law is obeyed in the range of 0.02 - 0.18 microg ml(-1), with an effective molar absorptivity at 630 nm and the relative standard deviation being 8.4 x 10(5) dm3 mol(-1) cm(-1) and 1.08% (n = 10). This method is about 70-times more sensitive than the Elson-Morgan method. The method was successfully applied to the assay of glucosamine in actual samples. 相似文献
413.
Ayumu Niida Yoshikazu Sasaki Hirokazu Tamamura Akira Otaka 《Tetrahedron letters》2005,46(24):4183-4186
Regio- and stereoselective anti-SN2′ alkylation of γ-phosphoryloxy-α,β-unsaturated-δ-lactams with organocopper reagents allowing the preparation of N-alkylated-α,δ-substituted-β,γ-unsaturated-δ-lactams as highly functionalized diketopiperazine mimetics is presented. 相似文献
414.
415.
Naoya Ogata Kohei Sanui Yoshikazu Hosoda Hiroyuki Nakamura 《Journal of polymer science. Part A, Polymer chemistry》1976,14(4):783-792
Polycondensation of diethyl 2,3,4,5-tetrahydroxyadipate with various diamines was carried out in solutions under mild conditions. The polycondensation reaction occurred rapidly even at room temperature in polar solvents such as alcohols, and in aqueous solution a cyclic product was obtained instead of linear polymers although the reaction with diamines was completed within several minutes. Polymers obtained from diethyl 2,3,4,5-tetrahydroxyadipate were a linear polyamide having pendant hydroxyl groups, which decomposed on heating at around 200°C. A solid-phase polycondensation of the precursor polyamide yielded a high molecular weight polyamide. 相似文献
416.
417.
The title asymmetric synthesis has been developed by featuring bromolactonization of (−)-acetals, derived from 2-acetyl-3,4-dihydronaphthacene-6,11-diones and (2R,3R)-(+)-N,N,N′,N′-tetraalkyltartaric acid diamides, as a key diastereoselective reaction. The produced bromolactone mixtures could be readily converted to the highly optically active key synthetic intermediates of 4-demethoxy- and 11-deoxy-4-demethoxyanthracyclinones. 相似文献
418.
Yoshikazu Shizuri Seiji Kosemura Shosuke Yamamura Hideyuki Furukawa Kazuaki Kawai Nobuo Okada 《Tetrahedron letters》1984,25(15):1583-1584
13C NMR spectroscopy using INADEQUATE pulse sequence method has been used to deduce the labelling patterns of the three metabolites of B. derived from [1,2-13C]acetate, indicating that their carbon skeletons consist of two different units [CH3COCH2COCH2COS-Enzyme and CH3COCH2COS-Enzyme]. 相似文献
419.
Kanazawa H Tsubayashi A Nagata Y Matsushima Y Mori C Kizu J Higaki M 《Journal of chromatography. A》2002,950(1-2):303-308
The chiral separation of loxoprofen was achieved on a chiral column with UV and circular dichroism (CD) detection. The good resolution of four loxoprofen stereoisomers was obtained. The column used for the chiral separation was Chiralcel OJ column (250 x 4.6 mm) using hexane-2-propanol-trifluoroacetic acid (95:5:0.1), as an eluent. The flow-rate was 1.0 ml/min and the detection was at 225 nm. In addition, CD and UV spectra were obtained by stopped flow scanning. The method allows the determination of the stereoisomers of loxoprofen in human plasma after the administration of therapeutic dose of the racemic drug, thus HPLC with CD detector is useful for the stereospecific determination of loxoprofen products in biological samples. 相似文献
420.
A bound for global solutions of semilinear heat equations 总被引:13,自引:0,他引:13
Yoshikazu Giga 《Communications in Mathematical Physics》1986,103(3):415-421
We show that global positive solutions of the initial-boundary value problem foru
t
=u+u
p
are bounded, provided thatp>1 is subcritical. Our bound depends only on sup norm of the initial data and is useful to classify initial data by the asymptotic behavior of the solutions as time tend to infinity.Partially supported by the Sakkokai Foundation 相似文献