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81.
Yuhei Yamamoto Hiroo Mizuno Takayuki Tsuritani Toshiaki Mase 《Tetrahedron letters》2009,50(42):5813-5815
A practical one-pot synthesis of N,N′,N″-trisubstituted guanidines via Tiemann rearrangement involving the reaction of α-chloroaldoxime O-methanesulfonates with alkyl amines is disclosed. 相似文献
82.
Y Shimizu H Morimoto M Zhang T Ohshima 《Angewandte Chemie (International ed. in English)》2012,51(34):8564-8567
The combination of an ammonium salt and ethylenediamine promotes deacylation of a variety of unactivated amides to give the corresponding amines in high yields without the use of strong acids or bases. The reactions proceed without special care regarding air and moisture, and tolerate a wide range of functional groups. 相似文献
83.
[reaction: see text] The skeletal reorganization of enynes is achieved by the presence of InCl(3) as the catalyst. The reaction of enynes having a terminal acetylenic moiety proceeds in a stereospecific manner to give 1-vinylcycloalkenes. The reaction of enynes containing an alkyl group on the acetylenic terminal carbon resulted in a new type of skeletal reorganization to give 1-allylcycloalkenes, formation of which involves a double cleavage of the C-C double bond and the triple bond. 相似文献
84.
Photoluminescence (PL) dynamics in single-walled carbon nanotubes (SWNTs) has been studied by the femtosecond excitation correlation method with a 150 fs time resolution. The SWNT samples were synthesized by different methods and suspended in gelatin films or D2O solutions. The PL dynamics of SWNTs depends on the local environment surrounding the SWNTs rather than the synthesis methods. The very weak temperature dependence of tauPL and the environment-dependent tauPL reveal that the PL relaxation process is dominated by the interplay between free excitons and weakly localized excitons. 相似文献
85.
Shintaro HigeNaoki Shiota Yuhei KobayashiTakashi Wakabayashi Tomohiro SatoYoshitane Imai 《Tetrahedron》2012,68(48):9999-10004
Three types of supramolecular benzoheterocyclic host complexes were successfully prepared using (1R,2S)-2-amino-1,2-diphenylethanol and three types of benzoheterocyclic (benzothiophene, benzofuran, and benzopyrrole) acid derivatives. The host complexes had one-dimensional (1D) channel-like cavities that were formed by the assembly of two-component 21-helical columnar network structures, which included guest alcohol molecules. The release behavior of the guest molecules could be tuned by the type of heterocyclic ring in the supramolecular host complex. 相似文献
86.
Kazuo Arakawa Tadao Seguchi Yuhei Watanabe Naohiro Hayakawa 《Journal of polymer science. Part A, Polymer chemistry》1982,20(9):2681-2692
Oxygen consumption and yield of oxidation products during γ-irradiation were studied on five types of polyethylene (PE), ethylene–butene copolymer (EB), and ethylene–propylene copolymer (EPR) using gas chromatography, mass spectrography, and high-resolution NMR. Samples were irradiated in oxygen under pressure from 0 to 500 torr by 60Co γ-rays up to 20 Mrad at 22–25°C. In enough oxygen, oxygen consumption and yield of oxidation products are independent of oxygen pressure for low-density PE, EB, and EPR. The G values of oxygen consumption were 14–18.4 for PE, 11.6 for EB at 1 × 106 rad/h, and 8.3 for EPR at 2 × 105 rad/h. The oxidation products determined were carboxylic acid (? CH2? CO? OH), H2O, CO2, and CO. The oxygen consumption and oxidation products for PE were found to increase with increasing crystallinity. 相似文献
87.
Katsuhiko Fujio Tsunehiro Mitsui Hiroshi Kurumizawa Yoshikazu Tanaka Yuhei Uzu 《Colloid and polymer science》2004,282(3):223-229
In order to investigate the effect of added salt on micelle size, shape, and structure the solubilization of Orange OT in aqueous NaBr solutions of decylpyridinium bromide (DePB), dodecylpyridinium bromide (DPB), tetradecylpyridinium bromide (TPB), and hexadecylpyridinium bromide (CPB) has been examined. The solubilization powers of DePB and DPB micelles increase with increasing NaBr concentration up to 2.86 and 3.07 mol dm–3, respectively, but above these concentrations remain unaltered. This suggests that spherical micelles of DePB and DPB can have a maximum and constant size at NaBr concentrations higher than these threshold concentrations. On the other hand, the solubilization powers of TPB and CPB micelles increase in the whole range of NaBr concentration studied. The dependencies of the solubilization powers of their micelles on the counterion concentration change at 0.10 and 0.03 mol dm–3 NaBr, respectively, as suggests that TPB and CPB micelles undergo the sphere–rod transition at those concentrations. Orange OT is a more suitable probe for detecting the presence of the maximum- and constant-size spherical micelle than Sudan Red B. 相似文献
88.
Yuhei Katsuma Linlin Wu Zhenyang Lin Seiji Akiyama Makoto Yamashita 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(1):323-327
The diboration of the C≡N bond in organic nitriles, and the N=N bond in azobenzene and pyridazine, by the highly Lewis‐acidic tetra(o‐tolyl)diborane(4) are reported. In the reactions with nitriles, azobenzene, and pyridazine, the addition of diborane(4) to the C≡N and N=N bonds was observed. Conversely, the N=N bond in phthalazine was cleaved by an addition/rearomatization sequence. 相似文献
89.
Jukiya Sakamoto Yuhei Umeda Kenta Rakumitsu Prof. Dr. Michinori Sumimoto Prof. Dr. Hayato Ishikawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13516-13524
A collective synthesis of glycosylated monoterpenoid indole alkaloids is reported. A highly diastereoselective Pictet–Spengler reaction with α-cyanotryptamine and secologanin tetraacetate as substrates, followed by a reductive decyanation reaction, was developed for the synthesis of (−)-strictosidine, which is an important intermediate in biosynthesis. This two-step chemical method was established as an alternative to the biosynthetically employed strictosidine synthase. Furthermore, after carrying out chemical and computational studies, a transition state for induction of diastereoselectivity in our newly discovered Pictet–Spengler reaction is proposed. Having achieved the first enantioselective total synthesis of (−)-strictosidine in just 10 steps, subsequent bioinspired transformations resulted in the concise total syntheses of (−)-strictosamide, (−)-neonaucleoside A, (−)-cymoside, and (−)-3α-dihydrocadambine. 相似文献
90.
Triplet superconductors such as Sr2RuO4 and NaxCoO2·yH2O are now found to be p-wave (px±ipy) or f-wave ((px±ipy)coscpz) superconductors. In conventional singlet superconductors, vortices are quantized because phase of order parameter must rotate by 2π around a vortex. But triplet superconductors have a degree of freedom of spin, which is described by d-vector. The d-vector and phase can rotate by π around a vortex, separately. Therefore appearance of HQVs is predicted. Theoretically, it is found that a pair of HQVs is more stable than a singly quantized vortex, for several parameter regions.In this study, in order to investigate quasi-particle bound states around two vortices in s-wave superconductors, we have developed a new numerical method to solve the BdG equation for two vortices state, using Mathieu functions. We confirmed the validity of this method for two vortices state and applied it in case of a pair of vortices. And we solved it. 相似文献