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71.
Naofumi Naga Ayaka Okada Yuka Satoh Hidemitsu Furukawa Takahiro Yamamoto 《Liquid crystals》2016,43(11):1616-1625
Organic–inorganic hybrid liquid crystal (LC) gels have been synthesised by the thiol-ene reaction of a multifunctional cyclic siloxane, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (TVMCTS) and alkane dithiols, 1,6-hexanedithiol (HDT) or 1,9-decanedithiol (DDT), in LC matrices, 4-cyano-4?-pentylbiphenyl (5CB) or 4′-n-octyl-4-cyano-biphenyl (8CB). The LC gels were prepared in an isotropic phase at 70°C or mesophases at 25°C using radical initiators. The phase transition temperatures from a mesophase to an isotropic phase of the resulting gels were lower than those of the original LCs. The gels containing 8CB (8CB gels) prepared at 25°C showed two phase transitions: smectic-to-nematic and nematic-to-isotropic transitions. By contrast, the 8CB gels synthesised in the isotropic phase showed only one phase transition from smectic phase directly to isotropic phase. Reaction conversions in the LC gels prepared at 70°C were higher than that in the gels prepared at 25°C. Scanning microscopic light scattering analysis of the LC gels cleared homogeneous small size mesh with a small amount of large defect. Polarisation micrographs of the LC gels showed framed optical textures derived from the LC molecules at room temperature. The LC gels containing more than 90 wt% of LC showed electro-optic response. 相似文献
72.
Ayaka Sasaki 《Tetrahedron letters》2009,50(32):4637-4638
First total synthesis of (−)-pyriculariol, a phytotoxin isolated from rice blast fungus, Magnaporthe grisea, was achieved to determine the absolute configuration of the natural product to be 5′R,6′S. The key step was Stille coupling reaction using microwave irradiation from −78 °C to control the reaction. 相似文献
73.
A supramolecular chiral host consisting of N-(2-naphthoyl)-L-aspartic acid (L-1) and meso-1,2-diphenylethylenediamine (2) is effective in enantioseparation of 1-arylethanols (up to 96% ee with 100% inclusion ratio). Here we report three different methods to prepare the inclusion crystals and discuss the chiral recognition mechanism on the basis of X-ray crystallography results. 相似文献
74.
Reaction of p-substituted phenols 2 with a catalytic amount of 4-iodophenoxyacetic acid (1) and Oxone® as a co-oxidant in tetrahydrofuran (THF) or 1,4-dioxane-water gave the corresponding p-quinols 3 in excellent yields. Reaction of p-dialkoxyarenes 4 in 2,2,2-trifluoroethanol-water gave the corresponding p-quinones 5 in excellent yield without purification. These reactions provide efficient and practical methods for the preparation of p-quinols and p-quinones from p-substituted phenols and p-dialkoxyarenes, respectively. This quinone synthesis was applied to synthesis of blattellaquinone (13), the sex pheromone of the German cockroach Blattella germanica. 相似文献
75.
Bathini Madhusree S. Tanabe Ayaka Amaha ?ztürk Ryo Tatsukawa Nobuyuki Miyazaki Emin ?zdamar Orhan Aral Osman Samsun Bayram ?ztürk 《Fresenius' Journal of Analytical Chemistry》1997,359(3):244-248
Concentrations of butyltin compounds (BTs) were determined in harbour porpoise (Phocoena phocoena) collected from the Turkish coastal waters of the Black Sea. Total butyltin compounds (∑ BTs) in the liver were in the range
of 89–219 ng/g on a wet weight basis. The dibutyltin (DBT) residues were higher than those of tributyltin (TBT), suggesting
the degradation of TBT to DBT in the liver and the metabolic capacity comparable to other marine mammals. Any sex difference
and age-dependent accumulation of BTs residues were not found in harbour porpoises, but residue levels increased until maturity
and then remained constant. When compared with other marine mammals, the present results indicate that the Black Sea is also
contaminated with butyltin compounds, but to a lesser degree than coastal waters of developed nations. The biomagnification
factor in harbour porpoises was 0.8, which was comparable with pinnipeds and lower than cetaceans.
Received: 23 December 1996 / Revised: 15 April 1997 / Accepted: 16 April 1997 相似文献
76.
Both enantiomers and racemate of pyricuol, a phytotoxin isolated from the rice blast disease fungus, Magnaporthe grisea, have been synthesized by using Stille coupling and [2,3]-Wittig rearrangement reactions as the key steps. Both enantiomers induced dark necrotic lesions on rice leaves almost equally, but did not affect the growth of rice second leaf sheath and the germination of lettuce. Only natural enantiomer promoted the root growth of rice and lettuce. 相似文献
77.
Hajime Kameo Jun Yamamoto Ayaka Asada Hiroshi Nakazawa Hiroyuki Matsuzaka Didier Bourissou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(52):18959-18963
Metal–Lewis acid cooperation provides new opportunities in catalysis. In this work, we report a new type of palladium–borane cooperation involving anionic Pd0 species. The air‐stable DPB palladium complex 1 (DPB=diphosphine‐borane) was prepared and reacted with KH to give the Pd0 borohydride 2 , the first monomeric anionic Pd0 species to be structurally characterized. The boron moiety acts as an acceptor towards Pd in 1 via Pd→B interaction, but as a donor in 2 thanks to B‐H‐Pd bridging. This enables the activation of C?Cl bonds and the system is amenable to catalysis, as demonstrated by the hydro‐/deutero‐dehalogenation of a variety of (hetero)aryl chlorides (20 examples, average yield 85 %). 相似文献
78.
79.
Kajigaya H Tanaka KF Hayashi A Suzuki A Ishibashi T Ikenaka K Baba H 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2011,87(7):415-424
Sulfatide is a myelin glycolipid that functions in the formation of paranodal axo-glial junctions in vivo and in the regulation of oligodendrocyte differentiation in vitro. Cerebroside sulfotransferase (CST) catalyzes the production of two sulfated glycolipids, sulfatide and proligodendroblast antigen, in oligodendrocyte lineage cells. Recent studies have demonstrated significant increases in oligodendrocytes from the myelination stage through adulthood in brain and spinal cord under CST-deficient conditions. However, whether these result from excess migration or in situ proliferation during development is undetermined. In the present study, CST-deficient optic nerves were used to examine migration and proliferation of oligodendrocyte precursor cells (OPCs) under sulfated glycolipid-deficient conditions. In adults, more NG2-positive OPCs and fully differentiated cells were observed. In developing optic nerves, the number of cells at the leading edge of migration was similar in CST-deficient and wild-type mice. However, BrdU(+) proliferating OPCs were more abundant in CST-deficient mice. These results suggest that sulfated glycolipids may be involved in proliferation of OPCs in vivo. 相似文献
80.
Tomohiko Inomata Mayuka Hatano Yuya Kawai Ayaka Matsunaga Takuma Kitagawa Yuko Wasada-Tsutsui Tomohiro Ozawa Hideki Masuda 《Molecules (Basel, Switzerland)》2021,26(22)
To develop low-cost and efficient dye-sensitized solar cells (DSSCs), we designed and prepared three homoleptic Cu(I) complexes with asymmetric ligands, M1, M2, and Y3, which have the advantages of heteroleptic-type complexes and compensate for their synthetic challenges. The three copper(I) complexes were characterized by elemental analysis, UV-vis absorption spectroscopy, and electrochemical measurements. Their absorption spectra and orbital energies were evaluated and are discussed in the context of TD-DFT calculations. The complexes have high VOC values (0.48, 0.60, and 0.66 V for M1, M2, and Y3, respectively) which are similar to previously reported copper(I) dyes with symmetric ligands, although their energy conversion efficiencies are relatively low (0.17, 0.64, and 2.66%, respectively). 相似文献