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911.
Matsuda H Morikawa T Ishiwada T Managi H Kagawa M Higashi Y Yoshikawa M 《Chemical & pharmaceutical bulletin》2003,51(4):440-443
The methanolic extract and its fractions from the fresh flowers of Prunus mume SIEB. et ZUCC. were found to show scavenging effects on 1,1-diphenylpicryl-2-hydrazyl (DPPH) radical and superoxide. The fragrance constituents of P. mume were analyzed by GC-MS and a new polyacylated sucrose, prunose III, was isolated from the ethyl acetate-soluble fraction. The structure of prunose III was determined on the basis of chemical and physicochemical evidence as 4,3',4',6'-tetra-O-acetyl-6-O-p-coumaroylsucrose. In addition, the scavenging effects of the principal constituents on DPPH radical and superoxide were examined. 相似文献
912.
The hydrogenation of olefins using H2O or D2O as a hydrogen source and zinc metal as a reducing agent has been found to be catalyzed by a rhodium complex. α,β-Unsaturated ketones also underwent hydrogenation, affording the corresponding saturated ketones selectively. 相似文献
913.
Yang Y Nogami M Shi J Chen H Ma G Tang S 《The journal of physical chemistry. B》2005,109(11):4865-4871
The composite nanoparticles of Au-core capped by CdS shells of different thickness were prepared and assembled into densely packed 3-dimensional films by the layer-by-layer self-assembly (LBL) technique. These films exhibited the 3-dimensional structure of densely packed Au@CdS composite nanoparticles and the shell thickness was tunable by changing the concentration of Cd2+-thiourea complexes. These multilayer films exhibited enhanced third-order optical nonlinear responses and ultrafast response times (several picoseconds). The third-order nonlinear optical susceptibility of the film with the CdS shell thickness of 4.4 nm was estimated to be 1.48 x 10(-9) esu and the value decreases with the increase of the CdS shell thickness. The enhancement of the optical nonlinearity was explained based on the calculation according to the electrostatic approximation by the solution of Laplace's equation under the boundary conditions appropriate to the model of core-shell nanoparticles, and mainly attributed to localized electric field effects in the CdS shell region. Additionally, the nonlinearity was optimized by determination of the values of the dielectric constant and thickness of the different shell. 相似文献
914.
Kadota I Takamura H Sato K Ohno A Matsuda K Satake M Yamamoto Y 《Journal of the American Chemical Society》2003,125(39):11893-11899
The convergent total syntheses of gambierol (1) and 16-epi-gambierol (2) have been achieved. The ABC and FGH ring segments 4 and 5 were prepared from known compounds 6 and 13, respectively, by linear manners. The fragments prepared were connected by our own synthetic strategy including the intramolecular allylation of alpha-acetoxy ether followed by ring-closing metathesis to furnish the octacyclic ether 3. The diiodoalkene 45, prepared from 3, was converted to the Z-iodoalkene 50 via a novel and stereoselective hydrogenolysis followed by deprotection. Construction of the triene side chain was performed by the modified Stille coupling of 50 with the Z-vinylic stannane 41 to afford 1. The similar transformations were carried out on the epimeric octacycle 34 to give 2, which showed no toxicity against mice at the concentration of 14 mg/kg. 相似文献
915.
The synthesis of 1,1-dimethylcarba-2-penem derivatives via a Dieckmann-type cyclization and the use of a new method for removing the benzyl protecting group are reported. 相似文献
916.
917.
918.
919.
Fengyu Zhao Yutaka Ikushima Masayuki Shirai Takeo Ebina Masahiko Arai 《Journal of molecular catalysis. A, Chemical》2002,180(1-2)
The selective hydrogenation of cinnamaldehyde (CAL) was investigated using silica supported platinum catalysts in supercritical carbon dioxide. Selectivity to cinnamyl alcohol (COL) is enhanced as Pt0/Pt2+ ratio increases; namely, zero-valent metallic surface is beneficial to the formation of COL compared with less reduced surface. The influence of Pt0/Pt2+ ratio is more significant on the selectivity than on the total conversion. For the catalyst with small Pt0/Pt2+ value, the selectivity also depends on the degree of platinum dispersion. The selectivity to COL is higher for higher degree of platinum dispersion. The CO2 pressure did not affect the conversion and selectivity so much. 相似文献
920.
Takiguchi Yu Seo Min-Woong Kagawa Keiichiro Takamoto Hisayoshi Inoue Takashi Kawahito Shoji Terakawa Susumu 《Optical Review》2016,23(2):364-368
Optical Review - We propose a novel full-electronically controlled laser confocal microscope in which a liquid-crystal-on-silicon spatial light modulator and a custom CMOS imaging sensor are... 相似文献