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221.
Ruthenium‐Catalyzed Cycloisomerization of 2,2′‐Diethynyl‐ biphenyls Involving Cleavage of a Carbon–Carbon Triple Bond 下载免费PDF全文
Prof. Dr. Takanori Matsuda Kotaro Kato Tsuyoshi Goya Shingo Shimada Prof. Dr. Masahiro Murakami 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):1941-1943
A ruthenium complex catalyzes a new cycloisomerization reaction of 2,2′‐diethynylbiphenyls to form 9‐ethynylphenanthrenes, thereby cleaving the carbon–carbon triple bond of the original ethynyl group. A metal–vinylidene complex is generated from one of the two ethynyl groups, and its carbon–carbon double bond undergoes a [2+2] cycloaddition with the other ethynyl group to form a cyclobutene. The phenanthrene skeleton is constructed by the subsequent electrocyclic ring opening of the cyclobutene moiety. 相似文献
222.
Jun-Ichi Asakura Masakuni Yoshihara Takaaki Shindo Yoshio Matsubara Toshihisa Maeshima 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(3):371-377
The radical copolymerization of vinylidene chloride (Vc, M1) with 3(2-methyl)-6-methylpyridazinone (I, M2) was carried out in benzene, ethanol, phenol, and acetic acid at 60 and 80°C. The monomer reactivity ratios were found to vary with the reaction conditions. The linear correlationships were obtained by plotting the values of log r1 against those of V C[dbnd]O and V C[dbnd]C of monomers determined in the solvents. 相似文献
223.
The condensation heat transfer characteristic curves for a ternary vapor mixture of water, ethanol, and air (or nitrogen) under several ethanol concentrations and relatively low concentrations of air (or nitrogen) were measured. The effect of non-condensable gas on several different domains in the condensation curves was discussed. The effect of non-condensable gas in the domains controlled by the diffusion resistance and the filmwise condensation was not notable; whereas that in the domain dominated by the condensate resistance of dropwise mode was remarkable. Moreover, variations due to changes in non-condensable gas concentration of several characteristic points representing the curves were discussed. 相似文献
224.
Kazuhide Matsuda 《The Ramanujan Journal》2014,34(3):449-456
In this paper, we derive two interesting theta constant identities by considering determinant structures. One of the two identities which we obtained is given by the Pfaffian, and the other is expressed by the resultant. 相似文献
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226.
Yusuke Kawashima Mamoru Satoh Tatsuya Saito Takashi Matsui Fumio Nomura Hiroyuki Matsumoto Yoshio Kodera 《Biomedical chromatography : BMC》2013,27(6):691-694
We report a cyclic sample pooling technique devised in two‐dimensional liquid chromatography–electrospray ionization mass spectrometry (LC‐ESI‐MS) shotgun proteomics that renders deeper proteome coverage; we combined low pH reversed‐phase (RP) LC in trifluoroacetic acid in the first dimension, followed by cyclic sample pooling of the eluate and low‐pH RP‐LC in formic acid in the second dimension. The new protocol has a significantly higher resolving power suitable for LC‐ESI‐MS/MS shotgun proteomics. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
227.
Mina Sakuragi Naoto Aoyagi Yoshio Furusho Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2014,52(14):2025-2031
In this study, we investigated the CO2‐capture/release behavior of the polystyrene‐bearing cyclic amidine pendant groups, which was synthesized via free radical polymerization of HCl salt of the corresponding styrene monomer followed by neutralization. For comparison, we also prepared the polystyrene bearing N‐formyl‐1,3‐propanediamine pendant groups through the hydrolysis of the cyclic amidine group by treatment with an alkaline solution. First, we examined the CO2‐capture/release behaviors of the amidine and amine monomers in aqueous solution in terms of conductivity. The conductivity of a wet DMSO solution of the amidine monomer increased upon CO2 bubbling at 25 °C and reached a stationary value of about 11 mS/m, which indicated the formation of the bicarbonate salt. Conversely, the conductivity decreased to its original value upon N2 bubbling at 50 °C, reflecting the complete release of the trapped CO2 molecules. Both solutions showed the changes in the conductivity with quick responses, and no appreciable difference was observed between them. We then investigated the CO2‐capture/release behaviors of the amidine and amine polymers, by taking advantage of the binary system with polyethylene glycol, and found that the binary system with the amidine polymer captured and released CO2 more efficiently than that with the amine polymer. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2025–2031 相似文献
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229.
Dr. Yusaku Nomura Dr. Frédéric Thuaud Dr. Daisuke Sekine Prof. Dr. Akihiro Ito Satoko Maeda Dr. Hiroyuki Koshino Dr. Daisuke Hashizume Dr. Atsuya Muranaka Dr. Thomas Cruchter Prof. Dr. Masanobu Uchiyama Prof. Dr. Satoshi Ichikawa Prof. Dr. Akira Matsuda Prof. Dr. Minoru Yoshida Prof. Dr. Go Hirai Prof. Dr. Mikiko Sodeoka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(35):8387-8392
A synthetic methodology to access all possible stereoisomers of spectomycin A1 (SMA1) and A2 (SMA2) has been established through late-stage diversification. The key reaction for the construction of all four diastereomers is an intramolecular cyclization based on the umpolung of π-allyl palladium species with bis(pinacolato)diborane (B2(pin)2). Silyl group assisted direct benzylic oxidation of each isomer enabled construction of the fragile β-hydroxytetralone skeleton to provide the SMAs. The relative and absolute stereochemistry of SMA2 was also determined, and the absolute stereochemistry of SMA1 was extrapolated based on the optical rotation of SMA2. The axial chirality of SMAs is discussed based on circular dichroism spectra and DFT calculations, and it is concluded that the M isomer is predominant in solution. Biochemical assessment of all isomers in vitro revealed that the C9 hydroxyl group and dimeric structure were both important for protein SUMOylation-inhibitory activity. 相似文献
230.
Chikako Matsuda Ryo Igarashi Prof. Dr. Hiroshi Katagiri Dr. Takashi Murase 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(19):e202200132
Tri- and tetra-fluorinated [7]helicenes are photolabile and undergo a double fluorine atom transfer. Herein, we show that the transferred product further undergoes a skeletal transformation on silica gel. The transformation begins with activation of the allylic C−F bond on the silanol surface. Then, the resulting carbocation readily undergoes a regioselective nucleophilic aromatic substitution with water, depending on the position of the fluorine substituents. Hexafluoro-2-propanol also activated the allylic C−F bond and acted as a nucleophile. These findings support the generation of a highly reactive cationic electrophilic intermediate in the successive transformations involving fluorine atoms. 相似文献