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941.
Ruthenium-catalyzed enantioselective propargylation of indoles with propargylic alcohols affords the corresponding beta-propargylated indoles in good yields with a high enantioselectivity (up to 95% ee). A remarkable effect of the nature of the N-substituent of indoles is observed for the enantioselectivity of the propargylated indoles. The preparative method described in this paper may provide a novel protocol for asymmetric Friedel-Crafts alkylation of indoles using propargylic alcohols as a new type of electrophiles. 相似文献
942.
The fluxon dynamics in a long Josephson junction with a ferromagnetic insulating layer is investigated. It is found that the Josephson phase obeys a double sine-Gordon equation involving a bound pi fluxon solution, and the internal oscillations of the bound pair acting as a clock exhibit Lorentz reductions in their frequencies regarded as a relativistic effect in the time domain, i.e., time dilation. This is the complement to the Lorentz contraction of fluxons with no clock. A possible observation scheme is also discussed. 相似文献
943.
Indium Tribromide Catalyzed Coupling Reaction of Enol Ethers with Silyl Ketene Imines toward the Synthesis of β,γ‐Unsaturated Nitriles
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Dr. Yoshihiro Nishimoto Takashi Nishimura Prof. Dr. Makoto Yasuda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(50):18301-18308
Herein, a coupling reaction of enol ethers with silyl ketene imines in the presence of catalytic amounts of InBr3 and Me3SiBr is described. Kinetic studies have revealed that an indium catalyst and Me3SiBr accelerated the coupling process and the regeneration of the catalyst, respectively. Various types of enol ethers and silyl ketene imines are applicable. In addition, a formal synthesis of verapamil was achieved by using this novel coupling reaction. 相似文献
944.
Bond Formation and Coupling between Germyl and Bridging Germylene Ligands in Dinuclear Palladium(I) Complexes
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Dr. Makoto Tanabe Shumpei Omine Naoko Ishikawa Prof. Dr. Kohtaro Osakada Yoshihiro Hayashi Prof. Dr. Susumu Kawauchi 《Angewandte Chemie (International ed. in English)》2015,54(9):2679-2683
The dinuclear palladium(I) complexes [L(Ar2HGe)Pd(μ‐GeAr2)2Pd(GeHAr2)L] (Ar=Ph, p‐Tol; L=PMe3, tBuNC) contain terminal germyl and bridging germylene ligands with the experimentally observed Ge???Ge bond lengths of 2.8263(4) Å (L=PMe3) and 2.928(1) Å (L=tBuNC), which are close to the longest Ge? Ge bond reported to date [2.714(1) Å]. Significant Ge???Ge interactions between the germylene and germyl ligands (PMe3 complexes > tBuNC complexes) are supported by DFT calculations, Wiberg bond indices (WBI), and natural bond orbital (NBO) analyses. Exchanging tBuNC for PMe3 ligands increases the Ge???Ge interaction, and simultaneously activates two Pd? Ge bonds. Adding the chelating diphosphine 1,2‐bis(diethylphosphino)ethane (depe) to the PMe3 complexes results in the intramolecular coupling of germyl and germylene ligands followed by extrusion of a digermane. 相似文献
945.
Synthesis and Structure–Property Relationships of Phosphole‐Based π Systems and Their Applications in Organic Solar Cells
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Yoshihiro Matano 《Chemical record (New York, N.Y.)》2015,15(3):636-650
Phosphole is a chemically tunable heterole, and its π‐conjugated derivatives are potential candidates for optoelectronic materials. This account describes recent developments in the synthesis and structure–property relationships of π‐conjugated phosphole derivatives made by my research group. Thiophene–phosphole–styrene, phosphole–acetylene–arene, oligophosphole, polyphosphole, areno[c]phosphole, and phosphole–heterole π systems are synthesized using titanacycle‐mediated metathesis and palladium‐catalyzed cross‐coupling reactions. The structural, optical, and electrochemical properties of selected compounds are discussed. Initial results on some applications of thiophene–phosphole copolymers, acenaphtho[c]phospholes, and amine–terthiophene–phosphole donor–π–acceptor dyes in organic solar cells are described. These results give valuable information and guidelines for designing new phosphorus‐containing organic materials for molecular electronics. 相似文献
946.
Dr. Jun Matsumoto Prof. Dr. Masayuki Nakamori Tatsumasa Okamoto Prof. Dr. Asako Murata Prof. Dr. Chikara Dohno Prof. Dr. Kazuhiko Nakatani 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(63):14305-14309
Expanded CUG repeat RNA in the dystrophia myotonia protein kinase (DMPK) gene causes myotonic dystrophy type 1 (DM1) and sequesters RNA processing proteins, such as the splicing factor muscleblind-like 1 protein (MBNL1). Sequestration of splicing factors results in the mis-splicing of some pre-mRNAs. Small molecules that rescue the mis-splicing in the DM1 cells have drawn attention as potential drugs to treat DM1. Herein we report a new molecule JM642 consisted of two 1,3-diaminoisoquinoline chromophores having an auxiliary aromatic unit at the C5 position. JM642 alternates the splicing pattern of the pre-mRNA of the Ldb3 gene in the DM1 cell model and Clcn1 and Atp2a1 genes in the DM1 mouse model. In vitro binding analysis by surface plasmon resonance (SPR) assay to the r(CUG) repeat and disruption of ribonuclear foci in the DM1 cell model suggested the binding of JM642 to the expanded r(CUG) repeat in vivo, eventually rescue the mis-splicing. 相似文献
947.
Tanaka H Tsurumura T Aritake K Furubayashi N Takahashi S Yamanaka M Hirota E Sano S Sato M Kobayashi T Tanaka T Inaka K Urade Y 《Journal of synchrotron radiation》2011,18(1):88-91
Human hematopoietic prostaglandin synthase, one of the better therapeutic target enzymes for allergy and inflammation, was crystallized with 22 inhibitors and in three inhibitor-free conditions in microgravity. Most of the space-grown crystals showed better X-ray diffraction patterns than the terrestrially grown ones, indicating the advantage of a microgravity environment on protein crystallization, especially in the case of this protein. 相似文献
948.
Biswanath Dinda Sudhan Debnath Santanu Majumder Noriko Sato Yoshihiro Harigaya 《中国化学快报》2011,22(10):1233-1236
A new iridoid glucoside,10-O-veratroyleranthemoside(1) was isolated from the roots of Wendlandia tinctoria.The structure was established by spectroscopic(including 2D NMR) and chemical methods. 相似文献
949.
In this report, local electronic structures of steps and terraces on rutile TiO(2) single crystal faces were studied by second harmonic and sum frequency generation (SHG∕SFG) spectroscopy. We attained selective measurement of the local electronic states of the step bunches formed on the vicinal (17 18 1) and (15 13 0) surfaces using a recently developed step-selective probing technique. The electronic structures of the flat (110)-(1×1) (the terrace face of the vicinal surfaces) and (011)-(2×1) surfaces were also discussed. The SHG∕SFG spectra showed that step structures are mainly responsible for the formation of trap states, since significant resonances from the trap states were observed only from the vicinal surfaces. We detected deep hole trap (DHT) states and shallow electron trap (SET) states selectively from the step bunches on the vicinal surfaces. Detailed analysis of the SHG∕SFG spectra showed that the DHT and SET states are more likely to be induced at the top edges of the step bunches than on their hillsides. Unlike the SET states, the DHT states were observed only at the step bunches parallel to [1?1?1] [equivalent to the step bunches formed on the (17 18 1) surface]. Photocatalytic activity for each TiO(2) sample was also measured through methylene blue photodegradation reactions and was found to follow the sequence: (110) < (17 18 1) < (15 13 0) < (011), indicating that steps along [0?0?1] are more reactive than steps along [1?1?1]. This result implies that the presence of the DHT states observed from the step bunches parallel to [1?1?1] did not effectively contribute to the methylene blue photodegradation reactions. 相似文献
950.
Ge M Nagel U Hüvonen D Rõõm T Mamone S Levitt MH Carravetta M Murata Y Komatsu K Lei X Turro NJ 《The Journal of chemical physics》2011,135(11):114511
We report on the dynamics of two hydrogen isotopomers, D(2) and HD, trapped in the molecular cages of a fullerene C(60) molecule. We measured the infrared spectra and analyzed them using a spherical potential for a vibrating rotor. The potential, vibration-rotation Hamiltonian, and dipole moment parameters are compared with previously studied H(2)@C(60) parameters [M. Ge, U. Nagel, D. Hüvonen, T. R??m, S. Mamone, M. H. Levitt, M. Carravetta, Y. Murata, K. Komatsu, J. Y.-C. Chen, and N. J. Turro, J. Chem. Phys. 134, 054507 (2011)]. The isotropic part of the potential is similar for all three isotopomers. In HD@C(60), we observe mixing of the rotational states and an interference effect of the dipole moment terms due to the displacement of the HD rotation center from the fullerene cage center. 相似文献