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81.
Dr. Masahito Yoshida Dr. Koya Saito Dr. Hikaru Kato Prof. Dr. Sachiko Tsukamoto Prof. Dr. Takayuki Doi 《Angewandte Chemie (International ed. in English)》2018,57(18):5147-5150
The total synthesis of siladenoserinol A, an inhibitor of the p53–Hdm2 interaction, has been achieved. AuCl3‐catalyzed hydroalkoxylation of an alkynoate derivative smoothly and regioselectively proceeded to afford a bicycloketal in excellent yield. A glycerophosphocholine moiety was successfully introduced through the Horner–Wadsworth–Emmons reaction using an originally developed phosphonoacetate derivative. Finally, removal of the acid‐labile protecting groups, followed by regioselective sulfamate formation of the serinol moiety afforded the desired siladenoserinol A, and benzoyl and desulfamated analogues were also successfully synthesized. Biological evaluation showed that the sulfamate is essential for biological activity, and modification of the acyl group on the bicycloketal can improve the inhibitory activity against the p53–Hdm2 interaction. 相似文献
82.
83.
84.
Summary A manual method for predicting the detection ranges of fluorescent compounds for the HPLC-peroxyoxalate chemiluminescence
detection system is presented utilizing bis(4-nitro-2-(3,6,9-trioxadecyloxycarbonyl)phenyl) oxalate (TDPO) as a chemilumigenic
reagent. The generated chemiluminescence decay curves were measured on a photomultiplier and extrapolated to zero time based
on the first part of the decay curve. Dipyridamole, perylene, DNS-Ser, Rose Bengal, DNS-Asp, Trp-P-1, pyrencarboxylic acid
methyl ester, perfenazine, alimemazine, oxypertine, Glu-P-2, benzydamine and doxorubicin gave chemiluminescence intensity
(Icl) values of 3.2 × 106, 2.8 × 106, 2.3 × 105, 2.1 × 105, 1.9 × 105, 1.4 × 105, 9.4 × 103, 6.2 × 103, 4.2 × 103, 3.3 × 103, 2.3 × 103, 9.7 × 102 and 3.1 × 102, respectively. The reaction conditions for the HPLC-CL detection system were investigated and optimum conditions obtained. 相似文献
85.
K. Fuke K. Tsukamoto F. Misaizu 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1993,26(Z1):204-206
Photoionization thresholds of Si
n
(n=2–40) were examined by vacuum UV radiation (5.7–8.5 eV) generated by stimulated Raman scattering of narrow-bandwidth 193-nm radiation in high pressure hydrogen and deuterium gases. A strong threshold energy dependence on cluster size is observed, featuring major maxima at 10 and 20. The magic behavior atn=10 is consistent with the results of the photofragmentation and CID experiments reported previously. 相似文献
86.
87.
K. Matsumura J. Tsukamoto A. Takahashi 《Journal of polymer science. Part A, Polymer chemistry》1984,22(7):1551-1564
Cyanoacetylene can be polymerized from the vapor state onto an inactive surface of substrate at a temperature as low as 200°C. The polymerization first occurs by way of the carbon–carbon triple bond. The reaction product obtained at 1000°C contains nitrogen at a concentration as high as 13.7%. At least some of this nitrogen is in naphtiridine ring or rings similar to it. The product obtained at 400°C is amorphous, while the product obtained at 1000°C has at least partly graphite-like crystalline structures with an apparent crystallite size (Lc) of about 17 Å. The electric conductivities of the products obtained at 400, 700, and 1000°C are 7.7 × 10?2, 91, and 1600 S/cm, respectively. These values are extremely high compared to the pyrolized PAN treated at the same temperature. Electric conductivity of the product obtained at 400°C is well explained by the variable range hopping model in 3-dimensional amorphous materials. With the products obtained at the higher temperatures, conductivity cannot be accounted for by the hopping model. This is probably due to the development of graphite-like structure. 相似文献
88.
89.
Kinetic resolution of various α,α-difluoro-β-hydroxyketones was conducted by enantioselective hydrolysis of the corresponding acetates with lipase MY to afford optically active products. Both enantiomers of 3,3-difluoro-2-hydroxy-4-decanone were obtained in a highly enantioselective manner by screening enzymes and acyl groups. 相似文献
90.
Tatsuya Moriai Dr. Takamasa Tsukamoto Dr. Makoto Tanabe Dr. Tetsuya Kambe Prof. Dr. Kimihisa Yamamoto 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(51):23251-23255
The science of particles on a sub-nanometer (ca. 1 nm) scale has attracted worldwide attention. However, it has remained unexplored because of the technical difficulty in the precise synthesis of sub-nanoparticles (SNPs). We recently developed the “atom-hybridization method (AHM)” for the precise synthesis of SNPs by using a suitably designed macromolecule as a template. We have now investigated the chemical reactivity of alloy SNPs obtained by the AHM. Focusing on the coinage metal elements, we systematically evaluated the oxidation reaction of an olefin catalyzed by these SNPs. The SNPs showed high catalytic performance even under milder conditions than those used with conventional catalysts. Additionally, the hybridization of multiple elements enhanced the turnover frequency and the selectivity for the formation of the hydroperoxide derivative. We discuss the unique quantum-sized catalysts providing generally unstable hydroperoxides from the viewpoint of the miniaturization and hybridization of materials. 相似文献