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141.
A variety of 2-azabicyclo[2.1.0]pentanes were synthesized by the intramolecular nucleophilic substitution of cyclopropylmagnesium carbenoids with magnesium anilide. The 1-chlorocyclopropyl p-tolyl sulfoxides possessing an N-aryl-substituted aminomethyl group were prepared from dichloromethyl p-tolyl sulfoxide, α,β-unsaturated carboxylic acid esters, and anilines in four steps. The deprotonation of the amine with t-BuMgCl followed by sulfoxide/magnesium exchange of the sulfoxides with i-PrMgCl led to the generation of the cyclopropylmagnesium carbenoids possessing a magnesium anilide moiety. Subsequent intramolecular nucleophilic substitution of the cyclopropylmagnesium carbenoids occurred in a 4-exo-tet manner to give the 2-azabicyclo[2.1.0]pentanes. The optically active 2-azabicyclo[2.1.0]pentane was synthesized using a p-tolylsulfinyl group as a chiral auxiliary. 相似文献
142.
Reaction of 2-propargylphenylcarbamates with diphenyliodonium salts via Meyer-Schuster rearrangement
Hideki Minami Noriko Okamoto Takuya Sueda Takatsugu Sakaguchi Minoru Ishikura Reiko Yanada 《Tetrahedron letters》2017,58(45):4277-4280
The syntheses of 2,3-dihydro-4-quinolones from 2-propargylphenylcarbamates by one-pot tandem process that involves Meyer-Schuster rearrangement or arylative Meyer-Schuster rearrangement/Michael addition of carbamate nitrogen to the resulting vinyl ketones have been developed. Phenylcarbamates tethering tertiary propargyl alcohols underwent arylative Meyer-Schuster rearrangement/Friedel-Crafts alkylation to produce 2,3-dihydroindenones. 相似文献
143.
Development of sulfide glass-ceramic electrolytes for all-solid-state lithium rechargeable batteries
Akitoshi Hayashi Keiichi Minami Masahiro Tatsumisago 《Journal of Solid State Electrochemistry》2010,14(10):1761-1767
Development of Li2S–P2S5-based glass-ceramic electrolytes is reviewed. Superionic crystals of Li7P3S11 and Li3.25P0.95S4 were precipitated from the Li2S–P2S5 glasses at the selected compositions. These high temperature or metastable phases enhanced conductivity of glass ceramics
up to over 10−3 S cm−1 at room temperature. The original (or mother) glass electrolytes itself showed somewhat lower conductivity of 10−4 S cm−1 and have important role as a precursor for obtaining the superionic crystals, which were not synthesized by a conventional
solid-state reaction. The substitution of P2O5 for P2S5 at the composition 70Li2S·30P2S5 (mol%) improved both conductivity and electrochemical stability of glass-ceramic electrolytes. The all-solid-state In/LiCoO2 cell using the 70Li2S·27P2S5·3P2O5 (mol%) glass-ceramic electrolyte showed initial capacity of 105 mAh g−1 (gram of LiCoO2) at the current density of 0.13 mA cm−2 and exhibited higher electrochemical performance than that using the 70Li2S·30P2S5 glass-ceramic electrolyte. 相似文献
144.
Recent cosmological observations, such as the measurement of the primordial 4He abundance, CMB, and large scale structure, give preference to the existence of extra radiation component, ΔNν>0. The extra radiation may be accounted for by particles which were in thermal equilibrium and decoupled before the big bang nucleosynthesis. Broadly speaking, there are two possibilities: (1) there are about 10 particles which have very weak couplings to the standard model particles and decoupled much before the QCD phase transition; (2) there is one or a few light particles with a reasonably strong coupling to the plasma and it decouples after the QCD phase transition. Focusing on the latter case, we find that a light chiral fermion is a suitable candidate, which evades astrophysical constraints. Interestingly, our scenario predicts a new gauge symmetry at TeV scale, and therefore may be confirmed at the LHC. As a concrete example, we show that such a light fermion naturally appears in the E6-inspired GUT. 相似文献
145.
Resistivity and thermoelectric power were measured as a function of temperature and composition for Ge20BixSe70?xTe10 glasses (x = 0–11). The results were compared with the case of of Ge20BixSe80?x glasses to see on the electrical properties the influence of the substitution of Te for a part of Se. The glasses show n-type conduction for x ? 9, which was not affected by the substitution of Te. The resistivity was about three orders of magnitude lower for the glasses with x < 10, and remained almost the same for x ? 10, compared with the glasses not containing Te. From the composition dependence of the calculated concentration of covalent bonds in the glasses, it was proposed that the appearance of n-type conduction was closely related to the formation of a sufficient number of BiSe bonds and the disappearance of the bonds between two chalcogen atoms such as TeSe or SeSe bonds, and that the remarkably low resistivity in the present glasses with x < 10 was likely to be attributed to the formation of TeSe bonds. 相似文献
146.
Noboru Tohge Atsunori Matsuda Tsutomu Minami Yoshihiro Matsuno Shinya Katayama Yoshirou Ikeda 《Journal of Non》1988,100(1-3):501-505
A novel process has been developed to form fine patterns on glass substrates. The process consists of the following steps: (1) coating of gel film on a substrate, (2) patterning on the gel film, and (3) heat-treatment. The key point in this process is the control of hardening of the gel films by the addition of organic polymers such as polyethylene glycol (PEG). The addition of PEG increased the viscosity of the coating solutions and delayed the gelation time, but had little effect on the optical properties of the resultant heat-treated glass films. The newly developed process is expected to be applicable to the formation of the optical devices such as diffraction gratings and pre-groovesof optical memory disks. 相似文献
147.
High‐performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles 下载免费PDF全文
Yang Zhu Kei Morisato George Hasegawa Nirmalya Moitra Tsutomu Kiyomura Hiroki Kurata Kazuyoshi Kanamori Kazuki Nakanishi 《Journal of separation science》2015,38(16):2841-2847
The optimization of a porous structure to ensure good separation performances is always a significant issue in high‐performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high‐performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high‐performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high‐performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36 000 m?1. Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans‐stilbene with separation factor as 7 and theoretical plate number as 76 000 m?1 for cis‐stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long‐ established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes. 相似文献
148.
149.
In the present study, we synthesized dextran (MW = ca. 2,000 kDa)-based macromolecular probes containing multiple molecules
of alkaline phosphatase (ALP) as a signal-trigger enzyme and of biotin as an assembly mediator. The ALP and biotin molecules
were covalently attached into the dextran backbone after the formation of aldehyde groups into the macromolecule by periodate
oxidation. The synthesized probes contained 27–31 molecules of ALP in their macromolecules when 50-fold molar ratio of ALP
to the dextran was used for the synthesis. These probes provided 14–20 times stronger chemiluminescence (CL) than that of
the equimolar free ALP adsorbed on a nylon membrane. The velocity of the CL reaction of ALP-catalyzed adamantlyl-1,2-dioxetane
substrate was improved from a slower emission (glow type) of CL to a faster one (flash type). The CL signal integrated for
2 min under strongly alkaline conditions (pH 13.0) was about ten times greater than that obtained by the conventional conditions
(pH 9.5). Therefore, the synthesized macromolecular probe could be successfully utilized for the high-throughput CL detection
of biotin-conjugated anti-rabbit IgG antibody with a lower detection limit of 880 amol per spot on the nylon membrane. This
study provides analytical strategy for the rapid, convenient, and sensitive detection of target proteins in immunoassays. 相似文献
150.
Keisuke Yoshiki Hiroki Azuma Kazuhiko Yoshioka Mamoru Hashimoto Tsutomu Araki 《Optical Review》2005,12(5):415-419
We have investigated the fluorescence lifetime properties of 8 calcium ion probes, calcium-green-1, calcium green-2, calcium
green-5N, calcium orange, oregon green 488 BAPTA-6F, fluo-3, fluo-4, and fluo-5N. We found that the decay time of calcium
green-5N varied more sensitively with calcium concentration than calcium green-1 which was known to be a highly sensitive
probe. We have also found that the center of observable range of calcium concentration by fluorescence lifetime measurement
is lower than that by fluorescence intensity measurement. 相似文献