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排序方式: 共有322条查询结果,搜索用时 15 毫秒
81.
Uenishi J Hamada M Aburatani S Matsui K Yonemitsu O Tsukube H 《The Journal of organic chemistry》2004,69(20):6781-6789
Stereospecific substitutions of optically pure 1-(pyridinyl)ethyl methanesulfonates with various amines are described. The reaction of (R)- or (S)-1-(2-pyridinyl)ethyl methanesulfonate with primary amines, including amino acid esters, gives N-substituted (S)- or (R)-1-(2-pyridinyl)ethylamines (4) with inversion of the configuration. Secondary cyclic amines are also reacted with (R)-2 to give the corresponding substituted amines (5) in excellent yields. Optically pure and meso triamine ligands having two pyridine rings, (S,S)-4f and meso-4f, (S,S)-9e, (S,R)-9e, and (S,S)-9f, have been prepared in stereochemically pure form by this method. Not only the substitution reaction of optically active 2 but also that of 1-(4-pyridinyl)ethyl and 1-(3-pyridinyl)ethyl methanesulfonates 11 and 14 take place stereospecifcally with inversion of the chiral center. 相似文献
82.
Joerg Freitag You Yokoyama Hidetoshi Kuramochi Katsuya Kawamoto Kunio Nagahama Satoru Kato 《Fluid Phase Equilibria》2007
The solubilities of phenylalanine and tyrosine in supercritical carbon dioxide (SCCO2) were measured after derivatization as the N-acetyl amino acid ethyl ester, N-carbobenzoxy amino acid and N-acetyl amino acid. Using an SCCO2 flow system, a measuring method of the saturated solubilities of the derivatized amino acids was established in which the contact height of the extraction cell, i.e. a packed column, is increased till the concentration of a derivatized amino acid at the exit of the cell reaches a plateau. The solubilities of N-acetyl phenylalanine ethyl ester (APEE) exceeded 0.001 mole fraction, which is higher than those of caffeine produced in industrial SCCO2 processes. A possible way of separating the amino acid mixtures using polarity differences in different amino acid side chains was demonstrated using the solubility data of the N-acetyl-amino acid ethyl esters in SCCO2, as the solubilities of APEE are higher than those of N-acetyl tyrosine ethyl ester by two orders of magnitude. 相似文献
83.
Katsuma Hiraki Toshihiro Itoh Katsuya Eguchi Masayoshi Onishi 《Journal of organometallic chemistry》1983,241(1):C16-C20
Benzylchlorobis(triphenylphosphine)palladium(II) reacted with dimethyl acetylenedicarboxylate to give [Pd[C(CO2Me)=C(CH2Ph)(CO2Me)]Cl(PPh3)2] (II) and [(Ph3P)ClPdμ-C(CO2Me)=C(CO2Me)PdCl(PPh3) (III). Complexes II and III reacted with Tl(acac) to afford [PdC(CO2Me=C(CH2Ph)(CO2Me)-(acac)(PPh3)] and [(Ph3P)(acac)Pdμ-C(CO2Me)=C(CO2Me)Pd(acac)(PPh3)], respectively. 相似文献
84.
Noboro Nishii Katsuya Hashimoto Rokuro Okawara 《Journal of organometallic chemistry》1973,55(1):133-137
Several adducts of monoorganoantimony tetrachlorides, RSbCl4L (R = CH3, C6H5, p-CH3C6H4; L = HMPT, PyO, 4-CH3PyO, DMSO), were prepared. In the solid state all of these adducts are stable at room temperature. They are monomeric in solution, and the existence of hexacoordinate antimony is indicated. CH3SbCl4L (L = PyO, 4-CH3PyO) exists in two isomeric forms in solution and decomposes above 70° into CH3Cl and SbCl3L. CH3SbCl4(HMPT) decomposes in a similar manner even at room temperature. 相似文献
85.
Wang Z Zhang B Otsuka T Inoue K Kobayashi H Kurmoo M 《Dalton transactions (Cambridge, England : 2003)》2004,(15):2209-2216
We present the synthesis, characterization by IR, TGA, single crystal X-ray structure and magnetic properties of a novel series of NaCl-type frameworks of [AmineH(+)][Mn(HCOO)(3)(-)], templated by alkylammonium. The anionic NaCl-framework of [Mn(HCOO)(3)(-)] is counter-balanced by the alkylammonium cations located in the cavities of the framework to which they are hydrogen-bonded. The divalent manganese ions have octahedral geometry and are bridged by the formate in an anti-anti mode of coordination. All the compounds exhibit long-range antiferromagnetism below 9 K with a slight non-collinear arrangement of the moments. The canting, likely due to second-order spin-orbit coupling, is via a Dzyaloshinski-Moriya antisymmetric exchange mechanism. A spin-flop is observed in each case at fairly low fields. An orthorhombic to monoclinic transformation was observed for the protonated cyclotrimethyleneamine that is accompanied by localization of the cations into two positions below 240 K from the rapid dynamic flipping of the ring observed at room temperature. 相似文献
86.
87.
88.
Inside Back Cover: Electrical Network of Single‐Crystalline Metal Oxide Nanoclusters Wired by π‐Molecules (Angew. Chem. Int. Ed. 42/2014) 下载免费PDF全文
89.
Morikawa T Pan Y Ninomiya K Imura K Yuan D Yoshikawa M Hayakawa T Muraoka O 《Chemical & pharmaceutical bulletin》2010,58(10):1403-1407
Three iridoid glycosides, kankanosides L, M, and N, and two acyclic monoterpene glycosides, kankanosides O and P, were isolated from fresh stems of Cistanche tubulosa (Orobanchaceae) together with eight iridoid glycosides, five acyclic monoterpene glycosides, three phenylpropanoid glycosides, and four lignan glycosides. Their structures were elucidated on the basis of chemical and physicochemical evidence. 相似文献
90.
Hidetoshi Nakano Katsuya Oguri Yasuaki Okano Tadashi Nishikawa 《Applied Physics A: Materials Science & Processing》2010,101(3):523-531
We investigated spatiotemporal evolution of expanding ablation plume of aluminum created by a 100-fs, 1014–1015-W/cm2 laser pulse. For diagnosing dynamic behavior of ablation plume, we employed the spatiotemporally resolved X-ray absorption
spectroscopy (XAS) system that consists of a femtosecond-laser-plasma soft X-ray source and a Kirkpatrick–Baez (K–B) microscope.
We successfully assigned the ejected particles by analyzing structure of absorption spectra near the L
II,III absorption edge of Al, and we clarified the spatial distribution of Al+ ions, Al atoms, and liquid droplets of Al in the plume. We found that the ejected particles strongly depend the irradiated
laser intensity. The spatial distribution of atomic density and the expansion velocity of each type of particle were estimated
from the spatiotemporal evolution of ablation particles. We also investigated a temperature of the aluminum fine particles
in liquid phase during the plume expansion by analyzing the slope of the L
II,III absorption edge in case of 1014-W/cm2 laser irradiation where the nanoparticles are most efficiently produced. The result suggests that the ejected particles travel
in a vacuum as a liquid phase with a temperature of about 2500 to 4200 K in the early stage of plume expansion. 相似文献