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961.
Masato Noguchi Tsukasa Fujieda Wei Chun Huang Masaki Ishihara Atsushi Kobayashi Shin‐ichiro Shoda 《Helvetica chimica acta》2012,95(10):1928-1936
A facile and practical method for synthesis of sugar oxazolines (=dihydrooxazoles) from the corresponding N‐acetyl‐2‐amino sugars has been developed by using 2‐chloro‐1,3‐dimethyl‐1H‐benzimidazol‐3‐ium chloride (CDMBI) as a dehydrative condensing agent. The intramolecular dehydrative reaction between the 2‐acetamido group and the anomeric OH group of unprotected N‐acetyl‐2‐amino sugars took place smoothly in H2O, leading to the formation of a 1,2‐oxazoline (=4,5‐dihydrooxazole) moiety in good yield. Since the reaction proceeds in H2O without using any protecting groups, the resulting oxazolines can be utilized as effective glycosyl donors for the subsequent enzymatic glycosylation. We have successfully demonstrated a highly efficient chemoenzymatic transglycosylation of a disialo‐oligosaccharide moiety to p‐nitrophenyl N‐acetylglucosaminide catalyzed by a mutant endo‐N‐acetylglucosaminidase without isolating disialo‐oligosaccharide oxazoline as synthetic intermediate. 相似文献
962.
Masaki Matsui Takahiro Shiota Yasuhiro Kubota Kazumasa Funabiki Jiye Jin Tsukasa Yoshida Shinji Higashijima Hidetoshi Miura 《Tetrahedron》2012,68(22):4286-4291
The effect of N-(2-alkoxyphenyl) group in double rhodanine indoline dye on the performance of zinc oxide dye-sensitized solar cell was examined. Both Jsc and Voc were improved by introducing long alkoxy group due to prevention of H-aggregates formation and inhibition of electron recombination from zinc oxide surface to electrolyte. 相似文献
963.
Aoi Kimishima Tomoyasu Hirose Akihiro Sugawara Takanori Matsumaru Kaoru Nakamura Ken Katsuyama Masaki Toda Hirokazu Takada Rokuro Masuma Satoshi Ōmura Toshiaki Sunazuka 《Tetrahedron letters》2012,53(23):2813-2816
Luminamicin (1) was found to exhibit selective antibacterial activity against anaerobic bacteria by our group in 1985. The concise structure of 14-membered lactone of 1 was synthesized. Construction of a versatile enol ether moiety was achieved by Stille cross coupling via hydrostanylation of the ethynyl ether, and a maleic anhydride moiety was derived from the furan constitution by the oxidation after the macrolactonization at a late-stage. 相似文献
964.
965.
966.
Basic phenomena of the reduction of carbon dioxide to reusable organic materials including methane and methanol were investigated
by using a radio frequency impulse discharge in a low gas pressure range without catalysis. The discharge took place under
different discharge parameters such as voltage, gas flow rate, gas-mixing ratio, and gas residence time, where the carbon
dioxide was mixed with hydrogen at total gas pressure of 1–10 Torr. Organic materials such as methane and methanol were observed.
Carbon monoxide was a major product from carbon dioxide. Methane was the dominant organic species produced by the discharge.
The concentration of methane increased with discharge voltage, and its volume fraction attained 10–20% of the products containing
carbon that came from carbon dioxide. This fraction was also dependent on the mixing ratio of carbon dioxide and hydrogen.
We also observed the formation of methanol, though its fraction was low, a few %, compared with methane. 相似文献
967.
Oral prochlorperazine (PCZ), an antiemetic, undergoes extensive first-pass metabolism. The study developed a simultaneous analytical method for PCZ and its major metabolites, prochlorperazine sulfoxide (PCZSO), N-demethylprochlorperazine (NDPCZ) and 7-hydroxyprochlorperazine (PCZOH), in human plasma using an isocratic liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Deproteinized plasma specimens were separated using a 3 μm particle size octadecylsilyl column, and the run time was 10 min. The calibration curves were linear over the concentration ranges of 0.01-40 μg/L for PCZ, NDPCZ and PCZOH, and 0.05-80 μg/L for PCZSO. The intra- and inter-assay precisions and accuracies were within 7.0 and 99-104% and within 9.0 and 99-105%, respectively. The lower limits of quantification in human plasma were 10 ng/L for PCZ, NDPCZ and PCZOH, and 50 ng/L for PCZSO. The validated method was applied to the determination of plasma samples in 37 cancer patients receiving PCZ. Large interindividual variations were observed in plasma concentrations of PCZ, PCZSO, NDPCZ and PCZOH (relative standard deviation, 89.4, 88.7, 86.4 and 78.2%, respectively). In conclusion, this simultaneous LC-MS/MS method with acceptable analytical performance can be helpful for evaluating the pharmacokinetics of PCZ, including the determination of its metabolites in cancer patients and in clinical research. 相似文献
968.
M Goto A Wilk K Kataoka S Chodankar N Tamai M Fukui J Kohlbrecher HO Ito H Matsuki 《Langmuir : the ACS journal of surfaces and colloids》2012,28(33):12191-12198
The myristoylpalmitoylphosphatidylcholine (MPPC) bilayer membrane shows a complicated temperature-pressure phase diagram. The large portion of the lamellar gel (L(β)'), ripple gel (P(β)'), and pressure-induced gel (L(β)I) phases exist as metastable phases due to the extremely stable subgel (L(c)) phase. The stable L(c) phase enables us to examine the properties of the L(c) phase. The phases of the MPPC bilayers under atmospheric and high pressures were studied by small-angle neutron scattering (SANS) and fluorescence spectroscopy using a polarity-sensitive fluorescent probe Prodan. The SANS measurements clearly demonstrated the existence of the metastable L(β)I phase with the smallest lamellar repeat distance. From a second-derivative analysis of the fluorescence data, the line shape for the L(c) phase under high pressure was characterized by a broad peak with a minimum of ca. 460 nm. The line shapes and the minimum intensity wavelength (λ″(min)) values changed with pressure, indicating that the L(c) phase has highly pressure-sensible structure. The λ″(min) values of the L(c) phase spectra were split into ca. 430 and 500 nm in the L(β)I phase region, which corresponds to the formation of a interdigitated subgel L(c) (L(c)I) phase. Moreover, the phase transitions related to the L(c) phase were reversible transitions under high pressure. Taking into account the fluorescence behavior of Prodan for the L(c) phase, we concluded that the structure of the L(c) phase is highly probably a staggered structure, which can transform into the L(c)I phase easily. 相似文献
969.
Richard I. Thomson Dr. Christopher M. Pask Dr. Gareth O. Lloyd Prof. Masaki Mito Prof. Jeremy M. Rawson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(28):8629-8633
The structure of the canted antiferromagnet β‐p‐NCC6F4CNSSN ( 1 ) was determined from synchrotron powder‐diffraction studies in the pressure range 0–21.6 kbar. Radical 1 crystallizes in the orthorhombic space group Fdd2, but undergoes an asymmetric contraction of the unit‐cell size with increasing pressure. At the molecular level, this contraction of the unit cell is simultaneously accommodated by: 1) an increase in twist angle between aryl and heterocyclic rings; and 2) a shortening of the intermolecular S ??? N contacts, which propagate the magnetic‐exchange pathway. DFT calculations based on the structures in this pressure range revealed an increase in the magnetic‐exchange interaction (J) with increasing pressure, and an excellent correlation was observed between J and the magnetic‐ordering temperature, which increased from 36 K at ambient pressure up to 70 K at 16 kbar. 相似文献
970.
Tadao Seguchi Kiyotoshi Tamura Akihiko Shimada Masaki Sugimoto Hisaaki Kudoh 《Radiation Physics and Chemistry》2012,81(11):1747-1751
The mechanism of polymer oxidation by radiation and thermal ageing was investigated for the life evaluation of cables installed in radiation environments. The antioxidant as a stabilizer was very effective for thermal oxidation with a small content in polymers, but was not effective for radiation oxidation. The ionizing radiation induced the oxidation to result in chain scission even at low temperature, because the free radicals were produced and the antioxidant could not stop the oxidation of radicals with the chain scission. A new mechanism of antioxidant effect for polymer oxidation was proposed. The effect of antioxidant was not the termination of free radicals in polymer chains such as peroxy radicals, but was the depression of initial radical formation in polymer chains by thermal activation. The antioxidant molecule was assumed to delocalize the activated energy in polymer chains by the Boltzmann statics (distribution) to result in decrease in the probability of radical formation at a given temperature. The interaction distance (delocalization volume) by one antioxidant molecule was estimated to be 5–10 nm by the radius of sphere in polymer matrix, though the value would depend on the chemical structure of antioxidant. 相似文献