排序方式: 共有102条查询结果,搜索用时 336 毫秒
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Dr. Jianlin Han Dr. Nataliya V. Lyutenko Dr. Alexander E. Sorochinsky Ayaka Okawara Dr. Hiroyuki Konno Dr. Sarah White Dr. Vadim A. Soloshonok 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(70):17510-17528
Over the recent years there has been a noticeable upsurge of interest in aza-analogs of tryptophan which are isosteric to the latter and found numerous applications in medicinal, bioorganic chemistry, and peptide research. In the present review article, five aza-tryptophan derivatives are profiled, including aza-substitution in the positions 2, on the five-membered ring, as well as in positions 4, 5, 6, and 7 on the six-membered ring. A detailed and comprehensive literature overview of the synthetic methods for the preparation of these aza-tryptophans is presented and general facets of the biological properties and most promising applications are discussed. 相似文献
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A series of dihalodiaryl(acetylacetonato)antimony(V) compounds, (p-Y-C6H4)2SbX2Acac (X=F, Cl, Br; Y=NO2, Cl, H, CH3, CH3O), were prepared. All of these compounds are monomeric and exist in solution as a mixture of two isomers both with chelated hexacoordinate configurations. From the temperature- and solvent-dependent PMR spectra of these compounds, it is concluded that the two isomers are in equilibrium in solution. The assignments of the PMR signals to the isomers were made by considering the effects of solvent and the substituents X and Y on the spectra. 相似文献
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Toshikazu Kurosaki Kyu Wan Lee Makoto Okawara 《Journal of polymer science. Part A, Polymer chemistry》1972,10(11):3295-3310
Polymers having stable nitroxyl free radicals, poly-4-methacryloylamino- and poly-4-methacryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyls, were synthesized from their precursor polymers by oxidizing them in a methanolic solution of hydrogen peroxide. The precursor polymers were prepared by radical polymerization of 4-methacryloyl-amino/oxy-2,2,6,6-tetramethylpiperidines in various solvents. These polymerizations in acetic acid were found to yield polymers of high molecular weight. The copolymers of the precursor monomers with styrene and methyl methacrylate were also prepared as precursor copolymers. These precursor polymers of a piperidine type were converted to the polymers having stable nitroxyl free radicals by the hydrogen peroxide method. In this report, it was assumed that the post-oxidation reaction introduced a nitroxyl group smoothly and quantitatively at room temperature. Elucidations of the stable radical formation and the electron spin behavior of the stable radical polymers were made in terms of elemental analyses, infrared, ultraviolet, and ESR spectroscopy. 相似文献
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Gohei Yoshida Hideo Kurosawa Rokuro Okawara 《Journal of organometallic chemistry》1977,131(2):309-315
Oxidative addition of ClCH2SCH3 to PtL4 afforded trans-PtL2(CH2SCH3)Cl (Ia, L = Ph3P;Ib, L = MePh2P). Treatment of I with NH4PF6 or Et3OBF4 in CH2C12 gave ionic species, [PtL2(CH2SCH3)]X (II, L = Ph3P, MePh2P, X = BF4, PF6), while similar treatment with MeSO3F in benzene yielded a new type of stable dimethylsulfonium methylide—platinum complex, trans-[PtL2(CH2SMe2)Cl] SO3F (IIIa, L = Ph3P; IIIb, L = MePh2P). Action of H2O2 on Ia gave [Pt(Ph3P)(μ-CH2SCH3)C1]2 (IV) and its triphenylarsine analog, [Pt(Ph3As)(μ-CH2SCH3)C1]2 (V) was prepared in one step by oxidative addition of ClCH2SCH3 to Pt(AsPh3)4. The structural difference between [Pt(Ph3P)(μ-CH2SCH3)C1]2 and Pd(Ph3P)- (CH2SCH3)C1 is discussed in terms of the difference in the ionization potential from d10 to d8 electronic state of metals. 相似文献
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Kentaro Ageishi Takeshi Endo Makoto Okawara 《Journal of polymer science. Part A, Polymer chemistry》1983,21(1):293-300
Polymers of viologen structure were prepared by oxidation of quinoid polymers obtained by the dimerization of alkylene dipyridinium salts with cyanide ion as catalyst. These polymers showed the behavior of polyelectrolytes and redox polymers that turn a deep blue when reduced chemically or electrically. 相似文献
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3-Acetylpyrrolidines are prepared from 5-methyl-5-vinyloxazolidines in a reaction which involves a directed 2-azonia-[3,3]-sigmatropic rearrangement. 相似文献
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Junzo Nokami Toshiyuki Yamamoto Mikio Kawada Mari Izumi Nobuko Ochi Rokuro Okawara 《Tetrahedron letters》1979,20(12):1047-1048
Malonic acid derivatives(gem-dicarboxylic acids) were converted to the corresponding ketones by the electrolysis. The reaction was employed for the synthesis of jasmones. 相似文献
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Takero Teramoto Mikito Deguchi Toshikazu Kurosaki Makoto Okawara 《Tetrahedron letters》1981,22(12):1109-1112
Preparations of optically active N-hydroxytartrimides were achieved. 1,3,4-Trihydroxysuccinimide ester of Z-L-alanine and 1-hydroxy-3,4-diacetoxysuccinimide ester of Z-D-alanine were allowed to react with D,L-alaninate to produce L-L form and D-D form of Z-Ala-Ala-OEt respectively (optical yield 100%). 相似文献