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排序方式: 共有1719条查询结果,搜索用时 15 毫秒
101.
Dr. Koichi Mitsudo Ren Matsuo Toki Yonezawa Haruka Inoue Dr. Hiroki Mandai Prof. Dr. Seiji Suga 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(20):7877-7881
The first electrochemical dehydrogenative C−S bond formation leading to thienoacene derivatives is described. Several thienoacene derivatives were synthesized by dehydrogenative C−H/S−H coupling. The addition of nBu4NBr, which catalytically promoted the reaction as a halogen mediator, was essential. 相似文献
102.
Tsuneo Imamoto Masatoshi Matsuo Taro Nonomura Kuniyuki Kishikawa Masao Yanagawa 《Heteroatom Chemistry》1993,4(5):475-486
Cyclohexyl(o-methoxyphenyl)menthyloxyphosphineborane and t-butyl(o-methoxyphenyl)menthyloxyphosphine-borane were prepared from dichlorocyclohexylphosphine and t-butyldichlorophosphine by successive treatments with (−)-menthol, o-methoxyphenylmagnesium bromide, and borane-THF complex. The separated pure diastereomers of each of the compounds underwent reaction with lithium naphthalenide to afford optically pure cyclohexyl(o-methoxyphenyl)phosphine-borane and t-butyl(o-methoxyphenyl)phosphine-borane, respectively. These secondary phosphine-boranes reacted readily with various electrophiles in the presence of bases with virtually net retention of configuration. A new chiral phosphine ligand, (S,S)-1,2-bis[cyclohexyl(o-methoxyphenyl)phosphino]ethane was synthesized via the optically pure phosphine-boranes. 相似文献
103.
Shahi Imam Reja Yuichiro Hori Takuya Kamikawa Kohei Yamasaki Miyako Nishiura Steven D. Bull Kazuya Kikuchi 《Chemical science》2022,13(5):1419
The ability to monitor proteolytic pathways that remove unwanted and damaged proteins from cells is essential for understanding the multiple processes used to maintain cellular homeostasis. In this study, we have developed a new protein-labeling probe that employs an ‘OFF–ON–OFF’ fluorescence switch to enable real-time imaging of the expression (fluorescence ON) and degradation (fluorescence OFF) of PYP-tagged protein constructs in living cells. Fluorescence switching is modulated by intramolecular contact quenching interactions in the unbound probe (fluorescence OFF) being disrupted upon binding to the PYP-tag protein, which turns fluorescence ON. Quenching is then restored when the PYP-tag–probe complex undergoes proteolytic degradation, which results in fluorescence being turned OFF. Optimization of probe structures and PYP-tag mutants has enabled this fast reacting ‘OFF–ON–OFF’ probe to be used to fluorescently image the expression and degradation of short-lived proteins.An “OFF–ON–OFF” fluorescence probe for real-time imaging of the expression (fluorescence ‘OFF’) and degradation (fluorescence ‘ON’) of short lived PYP-tag proteins in cellular systems. 相似文献
104.
Meccanica - The static deformation of symmetric bow limbs has been widely studied in the last century. However, asymmetries in shape and length which correspond to a more realistic situation, have... 相似文献
105.
H. Hanabata T. Matsuo H. Suga 《Journal of inclusion phenomena and macrocyclic chemistry》1987,5(3):325-333
Heat capacities of crystalline-cyclodextrin undecahydrate have been measured in the temperature range between 13 and 300K by use of a miniaturized adiabatic low-temperature calorimeter. A first-order phase transition occurred at 226K with a discontinuous entropy change of 45.0 ± 1.0J
K
–1 mol–1. The highly disordered nature of the high temperature phase was considered in relation to the entropy contribution. A glass transition phenomenon observed around 150K was ascribed to the freezing of a configurational change of the protons engaged in the four-membered hydrogen-bonded ring which appeared only in the low temperature phase. 相似文献
106.
Kentaro Yonesato Hiroyasu Ito Daisuke Yokogawa Kazuya Yamaguchi Kosuke Suzuki 《Angewandte Chemie (International ed. in English)》2020,59(38):16361-16365
Small Agn nanoclusters (n<10) have been emerging as promising materials as sensing, biolabeling, and catalysis because of their unique electronic states and optical properties. However, studying synthesis, structure determination, and exploration of their properties remain major challenges as a result of the low stability of small Ag nanoclusters. Herein, we synthesized an atomically precise face‐centered‐cubic‐type small {Ag7}5+ nanocluster supported by a novel triangular hollow polyoxometalate (POM) framework [Si3W27O96]18?. The cluster showed unique {Ag7}5+‐to‐POM charge transfer bands in both visible and UV light regions. Furthermore, this small {Ag7}5+ nanocluster exhibited an unprecedented ultrastability in solution, despite having exposed Ag sites that can be accessed by small molecules, such as O2, water, and solvents. 相似文献
107.
108.
Keika Hattori Kazuya Yamaguchi Junichiro Yamaguchi Kenichiro Itami 《Tetrahedron》2012,68(37):7605-7612
The palladium- and copper-catalyzed C–H arylation reactions of 1H- and 2H-indazoles with haloarenes are described. A PdCl2/phen/Ag2CO3/K3PO4 catalytic system is effective for the C–H arylation of 1H- and 2H-indazoles with haloarenes, whereas a less expensive CuI/phen/LiOt-Bu catalytic system is applicable to the C–H coupling of substituted 2H-indazoles and iodoarenes. The utility of newly developed catalyst was demonstrated in the rapid synthesis of YC-1 (an antitumor agent) and YD-3 (platelet anti-aggregating agent). These new reactions represent important direct functionalization tools of indazoles, well-known bioisosteres of pharmaceutically important indole core. 相似文献
109.
110.
The Gaussian expansion method (GEM) is applied to calculations of the nuclear excitations in the random-phase approximation (RPA). We adopt the mass-independent basis-set that is successful in the mean-field calculations. The RPA results obtained by the GEM are compared with those obtained by several other available methods in Ca isotopes, by using a density-dependent contact interaction along with the Woods–Saxon single-particle states. It is confirmed that energies, transition strengths and widths of their distribution are described by the GEM with good precision, for the 1−, 2+ and 3− collective states. The GEM is then applied to the self-consistent RPA calculations with the finite-range Gogny D1S interaction. The spurious center-of-mass motion is well separated from the physical states in the E1 response, and the energy-weighted sum rules for the isoscalar transitions are fulfilled reasonably well. Properties of low-energy transitions in 60Ca are investigated in some detail. 相似文献