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401.
Naofumi Naga Yoshikazu Ohkura Nanae Tagaya Haruhiko Tomoda 《Journal of polymer science. Part A, Polymer chemistry》2011,49(23):4935-4940
Alternating copolymerization of 9,9‐bis(3,6,9‐trioxadecyl)‐2,7‐dibromofluorene (ODFl) or 9,9‐bis(3,6‐dioxaheptyl)‐2,7‐dibromofluorene with Si containing divinyl compounds, divinyldiphenylsilane (VPS), or divinyldimethylsilane (VMS) is investigated using the Mizoroki–Heck reaction with palladium(II) acetate. The corresponding alternating copolymer is obtained in the copolymerization of ODFl with VPS. The copolymerization of ODFl with VMS yields low molecular weight oligomers. Optical properties of the ODFl–VPS copolymer have been investigated with UV–vis absorption and photoluminescence (PL) spectroscopy. The ODFl–VPS copolymer shows absorption peaks due to π–π* transition and intramolecular charge transfer through σ–π moiety at around 330 and 360–400 nm, respectively. An emission peak is observed at 450 nm in the PL spectrum of the ODFl–VPS copolymer, and the PL quantum yield is 0.19. The PL spectroscopy of ODFl–VPS copolymer is investigated in the presence of Li+, Na+, and K+, and the intensity of emission peak is decreased by those metal cations, especially by Na+. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011. 相似文献
402.
Kanako Miyachi Kenzo Moriyama Takako Yamaguchi Hiroshi Tominaga Shinichiro Kamino Yoshikazu Fujita 《Analytical sciences》2007,23(9):1103-1107
A simple and highly sensitive spectrophotometric method for the determination of spermine (Spm) was established based on the ternary complex formation reaction of Spm with o-hydroxyhydroquinonephthalein (QP) as a xanthene dye and manganese(II) as a metal ion in the presence of a dispersion agent. The apparent molar absorptivity at 555 nm and the relative standard deviation of the proposed method were 1.4 x 10(5) dm(3) mol(-1) cm(-1) and 0.50% (n = 10), respectively. In the method for flow-injection analysis (FIA), which employs a single-channel flow manifold system, a good linear relationship was observed over the 2 - 20 pg microl(-1) range of Spm by direct injection. 相似文献
403.
404.
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
405.
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
406.
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
407.
408.
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
409.
410.
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