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661.
Bo Sun Tatsuhiko Yoshino Motomu Kanai Shigeki Matsunaga 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(44):13160-13164
The synthesis of isoquinolines by site‐selective C H activation of O‐acyl oximes with a Cp*CoIII catalyst is described. In the presence of this catalyst, the C H activation of various unsymmetrically substituted O‐acyl oximes selectively occurred at the sterically less hindered site, and reactions with terminal as well as internal alkynes afforded the corresponding products in up to 98 % yield. Whereas the reactions catalyzed by the Cp*CoIII system proceeded with high site selectivity (15:1 to 20:1), use of the corresponding Cp*RhIII catalysts led to low selectivities and/or yields when unsymmetrical O‐acyl oximes and terminal alkynes were used. Deuterium labeling studies indicate a clear difference in the site selectivity of the C H activation step under Cp*CoIII and Cp*RhIII catalysis. 相似文献
662.
1A pseudo-schlieren technique is applied to the interferometric computed tomography (CT) measurement of three-dimensional
(3-D) shock waves discharged from a square open end and a pair of circular open ends in a shock tube experiment. The experiment
is performed for incident shock Mach numbers of 2.0 and 2.2 in nitrogen gas under supersonic post shock flow conditions at
the open end. The 3-D density-gradient distributions are evaluated from the CT data of the 3-D density distributions, and
are depicted in gray-scale CT images of the gradient magnitude and in pseudo-color CT images of the gradient component. The
resultant pseudo-schlieren CT images clearly illustrate the 3-D flow features of shock waves, contact surfaces, and the other
sharp density fronts. Their image characteristics and meaning in gas dynamics are discussed in comparison with the pseudo-color
images of the density. We demonstrate that the pseudo-schlieren CT technique is a useful tool for studying 3-D problems in
shock dynamics.
Communicated by K. Takayama
PACS 47.32.cd; 47.40.Nm; 47.80.jk 相似文献
663.
Masatoshi Ishida Hiroyuki Fujimoto Tatsuki Morimoto Shigeki Mori Motoki Toganoh Soji Shimizu 《Supramolecular chemistry》2017,29(1):8-16
Synthesis and properties of a novel meso-oxo carbaphlorin analogue embedded with an N-free pyrazole moiety are described. The N-benzyl precursor was prepared by a [3 + 1]-MacDonald condensation of N-benzyl pyrazole dialdehyde and β-alkyl-substituted tripyrrane dicarboxylic acid and subsequent oxidation by ferric chloride. Upon deprotection of the benzyl group, the resulting N-free oxophlorin analogue formed a unique supramolecular dimer through mutual hydrogen bonding interactions between the pyrazole NH and meso-carbonyl group. The assembled behaviour was characterised by various spectroscopies, X-ray crystallographic analysis and vapour pressure osmometry. Under the similar reaction conditions, the condensation of meso-phenyl-substituted tripyrrane derivative afforded an unprecedented tetrapyrrolic macrocycle fused with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone unit at their α-pyrrolic positions. The X-ray crystallographic analysis of the macrocycle revealed a twisted core structure, and nonaromatic nature was elucidated. 相似文献
664.
Yudai Suzuki Bo Sun Dr. Ken Sakata Dr. Tatsuhiko Yoshino Prof. Dr. Shigeki Matsunaga Prof. Dr. Motomu Kanai 《Angewandte Chemie (International ed. in English)》2015,54(34):9944-9947
The unique reactivity of [Cp*CoIII] over [Cp*RhIII] was demonstrated. A cationic [Cp*CoIII] catalyst promoted direct dehydrative C? H allylation with non‐activated allyl alcohols, thus giving C2‐allylated indoles, pyrrole, and phenyl‐pyrazole in good yields, while analogous [Cp*RhIII] catalysts were not effective. The high γ‐selectivity and C2‐selectivity indicated that the reaction proceeded by directing‐group‐assisted C? H metalation. DFT calculations suggested that the γ‐selective substitution reaction proceeded by C? H metalation and insertion of a C? C double bond, with subsequent β‐hydroxide elimination. The [Cp*CoIII] catalyst favored β‐hydroxide elimination over β‐hydride elimination. 相似文献
665.
An extension of the definition of primitivity of a real nonnegative matrix to matrices with univariate polynomial entries is presented. Based on a suitably adapted notion of irreducibility an analogue of the classical characterization of real nonnegative primitive matrices by irreducibility and aperiodicity for matrices with univariate polynomial entries is given. In particular, univariate polynomials with nonnegative coefficients which admit a power with strictly positive coefficients are characterized. Moreover, a primitivity criterion based on almost linear periodic matrices over dioids is presented. 相似文献
666.
667.
Prof. Dr. Tetsuo Okujima Chie Ando Dr. John Mack Dr. Shigeki Mori Dr. Ichiro Hisaki Dr. Takahiro Nakae Prof. Dr. Hiroko Yamada Prof. Dr. Keishi Ohara Prof. Dr. Nagao Kobayashi Prof. Dr. Hidemitsu Uno 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(41):13970-13978
An acenaphthylene‐fused cyclo[8]pyrrole was synthesized by using an oxidative coupling reaction of the corresponding 2,2′‐bipyrrole. Two conformational isomers 1 a and 1 b were isolated, and their molecular structures were elucidated by X‐ray crystallographic studies. The less‐polar and lower‐symmetry 1 b isomer can be converted into the 1 a isomer through a thermal ring flip. Application of the perimeter model developed by Michl to magnetic circular dichroism spectroscopic data and theoretical calculations demonstrate that there is a marked redshift of the near‐IR absorption maxima relative to cyclo[8]isoindole because there is a significant stabilization of the LUMO due to the differing effects of a fused ring expansion with acenaphthylene and benzene moieties on the frontier π molecular orbitals. 相似文献
668.
This article examines the accuracy of radiation thermometry in measuring the temperature of silicon wafers in a diffusion furnace. This technique uses optical guides to bring thermal radiation from the wafers to the outside of the furnace. The error due to veiling glare of a rod-type optical guide is 40°C and that of a prism-type is 0.5°C at steady state. 相似文献
669.
670.
Shigeki Habaue Hiroharu Ajiro Yoshio Okamoto 《Journal of polymer science. Part A, Polymer chemistry》2000,38(22):4088-4094
Ortho‐substituted styrenes, such as 2‐(N,N‐dimethylaminomethyl)styrene ( 1 ), 2‐(1‐pyrrolidinylmethyl)styrene ( 2 ), and 2‐[(S)‐2‐(1‐pyrrolidinylmethyl)‐1‐pyrrolidinylmethyl]styrene ( 3 ), were synthesized, and the effects of the ortho‐substituents on the polymerizability and stereoregularity of the obtained polymers using the anionic method were examined. The bulkiness and coordination of the ortho‐substituted amino groups to the counter cation significantly affected the polymerizability and stereochemistry of the obtained polymers. The anionic and radical polymerizations of 2 with a less hindered ortho‐substituent afforded polymers in good yields, whereas those of 1 and 3 resulted in lower yields. The anionic polymerization of 3 bearing an optically active diamine derivative at the ortho‐position with n‐butyllithium in toluene at 0 °C gave a polymer with a high stereoregularity and stable regular conformation based on the stereoregular backbone structure. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4088–4094, 2000 相似文献