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941.
Nohara T Kiyota Y Sakamoto T Manabe H Ono M Ikeda T Fujiwara Y Nakano D Kinjo J 《Chemical & pharmaceutical bulletin》2012,60(6):747-751
Several novel sulfides from acetone extracts of bulbs of garlic (Allium sativum L.), were identified and investigated. These were named garlicnins B(1) (1), C(1) (2), and D (3), and they were found to have the ability to control macrophage activation. Garlicnins B(1) (1) and C(1) (2) possess a new skeleton of cyclic sulfoxide and their structures of garlicnins B(1) (1) and C(1) (2) were characterized as 3,4-dimethyltetrahydrothiophene-S-oxide derivatives carrying the substitutions of a propenyl and a sulfenic acid, and an allyldithiine and a 1-propene-sulfenic acid (a), respectively. The mechanism of the proposed production of these compounds is discussed. Garlicnin D (3), dithiine-type, was estimated to be derived by addition of (a)+allyl thiosulfenic acid (b) derived from allicin. The identification of these novel sufoxides from onion and garlic accumulates a great deal of new chemistry to the Allium sulfide field, and future pharmacological investigations aid the development of natural, healthy foods and anti-cancer agents that could potentially prevent or combat disease. 相似文献
942.
Tsuyoshi Satoh Takahiro Tsuru Shotaro Ikeda Toshifumi Miyagawa Hitoshi Momochi Tsutomu Kimura 《Tetrahedron》2012,68(4):1071-1084
The addition reactions of α,β-unsaturated carbonyl compounds with dichloromethyl p-tolyl sulfoxide in the presence of NaHMDS or LDA resulted in the formation of adducts, 1-chlorocyclopropyl p-tolyl sulfoxides bearing a carbonyl group at the 2-position, in almost quantitative yields. The carbonyl group of the adducts was transformed to various ether groups to give 1-chlorocyclopropyl p-tolyl sulfoxides bearing an ether functional group at the 2-position in short steps. Treatment of these products with i-PrMgCl at low temperature afforded cyclopropylmagnesium carbenoids via the sulfoxide-magnesium exchange reaction. 1,5-Carbon–hydrogen insertion (1,5-CH insertion) reaction of the generated magnesium carbenoid intermediates took place to give 3-oxabicyclo[3.1.0]hexanes or bicyclo[3.1.0]hexanes bearing an ether group at the 4-position in moderate to good yields. When this procedure was carried out starting with enantiopure dichloromethyl p-tolyl sulfoxide, enantiopure 3-oxabicyclo[3.1.0]hexanes were obtained in good overall yields. These procedures provide a good way for the synthesis, including asymmetric synthesis, of multisubstituted 3-oxabicyclo[3.1.0]hexanes and bicyclo[3.1.0]hexanes from α,β-unsaturated carbonyl compounds and dichloromethyl p-tolyl sulfoxide in short steps. 相似文献
943.
Teigo Asai Yu-Ming Chung Hiroaki Sakurai Tomoji Ozeki Fang-Rong Chang Yang-Chang Wu Kouwa Yamashita Yoshiteru Oshima 《Tetrahedron》2012,68(29):5817-5823
The concomitant addition of a histone deacetylase inhibitor, suberoyl bis-hydroxamic acid, and a DNA methyltransferase inhibitor, RG-108, to the culture medium of Gibellula formosana, an entomopathogenic fungus, induced a significant increase in diversity of secondary metabolites. From the culture media were isolated two new highly oxidized ergosterols, formosterols A (1) and B (2), and five new isariotin analogs, 12′-O-acetylisariotin A (4), 1-epi-isariotin A (5), and isariotins K–M (6–8), together with 22,23-epoxy-3,12,14,16-tetrahydroxyergosta-5,7-dien-11-one (named formosterol C) (3), isariotins A (9), C (10), and E (11), TK-57-164A (12), and beauvericin (13). The NMR spectra, X-ray single crystallographic diffraction, and chemical transformations revealed the structures of the two new formosterols and five new isariotins. The stereochemistry of formosterol C (3) was deduced from its spectroscopic data. The side chains of formosterols A–C (1–3) contained cis-22,23-epoxide, which is rarely present in naturally occurring sterols and triterpenes. 相似文献
944.
Yuichi Hatsukawa Takahito Osawa Masumi Oshima Yosuke Toh Atsushi Kimura Mitsuo Koizumi Kazuyoshi Furutaka 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(1):143-145
In this study, the Ir concentrations in some standard rock samples were determined by using the multiple γ-ray detection method.
The use of the multiple γ-ray detection method, which was developed for nuclide quantification, yielded better resolution
and sensitivity than the ordinary singles γ-ray detection method. Iridium is one of the least abundant elements in Earth’s
crust, with an average mass fraction of 0.001 ppm in a crust rock. However, iridium is relatively more abundant (concentration:
0.5 ppm or more) in undifferentiated meteorites. Therefore iridium abundance anomalies in geological samples provide important
information about meteorite impact. The standard rock samples used in this study were SARM-76, FC-1 and FC-2. The SARM-76
was prepared from a platinum ore, and issued by the south African bureau of standards. FC-1 and FC-2 were obtained from fish
clay sediment samples from Stevens Klint, Denmark. 相似文献
945.
Takahashi Y Taura S Akiyama T Yamada S 《Langmuir : the ACS journal of surfaces and colloids》2012,28(24):9155-9160
A polythiophene thin film was fabricated on gold nanoparticle (AuNP)-deposited indium-tin-oxide (ITO) electrodes with electropolymerization, whereas AuNPs were predeposited on the ITO surface. A photocurrent via photoexcited polythiophene increased with AuNPs which was attributed to the localized surface plasmon resonance. Investigation of the AuNP-density dependence on the relative enhancement of photocurrent revealed the maximum effect at 14% of AuNP-density, while 68% of AuNP-density exhibited smaller photocurrent than the polythiophene electrode without AuNPs. We have revealed that the effects of AuNPs saturate in the fairly low density region, and that the excess AuNPs even in the range of submonolayer resulted in the decrement of photocurrents. 相似文献
946.
Mohsen Farahat Tsuyoshi Hirajima Keiko Sasaki Katsumi Doi 《Colloids and surfaces. B, Biointerfaces》2009,74(1):140-149
The adhesion of Escherichia coli onto quartz, hematite and corundum was experimentally investigated. A strain of E. coli was used that had the genes for expressing protein for silica precipitation. The maximum cell adhesion was observed at pH <4.3 for quartz and at pH 4.5–8.5 for corundum. For hematite, cell adhesion remained low at all pH values. The microbe–mineral adhesion was assessed by the extended DLVO theory approach. The essential parameters for calculation of microbe–mineral interaction energy (Hamaker constants and acid–base components) were experimentally determined. The extended DLVO approach could be used to explain the results of the adhesion experiments. The effect of E. coli on the floatability of three oxide minerals was determined and the results showed that E. coli can act as a selective collector for quartz at acidic pH values, with 90% of the quartz floated at 1.5 × 109 cells/ml. However, only 9% hematite and 30% corundum could be floated under similar conditions. By using E. coli and no reagents, it was possible to separate quartz from a hematite–quartz mixture with Newton's efficiency of 0.70. Removal of quartz from the corundum mixture was achieved by E. coli with Newton's efficiency of 0.62. 相似文献
947.
948.
949.
Nakayama R Matsubara H Fujino D Kobatake T Yoshida S Yorimitsu H Oshima K 《Organic letters》2010,12(24):5748-5751
Tin hydride mediated radical addition of organic halide to 2-(2,2,2-trifluoroethylidene)-1,3-dithiane 1-oxide has been devised. The reaction is equivalent to an unrealizable radical addition to trifluoromethylketene, providing useful α-trifluoromethyl carbonyl equivalents. The trifluoromethyl and the sulfoxide groups of the substrate play key roles for the success of the radical addition, lowering the barrier of the radical addition step and controlling the stereoselectivity of the reaction, which DFT calculations have elucidated. 相似文献
950.
Tsuyoshi Nakayama Ha Minh Hiep Satoshi Furui Yuji Yonezawa Masato Saito Yuzuru Takamura Eiichi Tamiya 《Analytical and bioanalytical chemistry》2010,396(1):457-464
DNA analysis with the polymerase chain reaction (PCR) has become a routine part of medical diagnostics, environmental inspections,
food evaluations, and biological studies. Furthermore, the development of a microscale PCR chip is an essential component
of studies aimed at integrating PCR into a micro total analysis system (μ-TAS). However, the occurrence of air bubbles in
microchannels complicates this process. In this study, we investigated a new technique based on the fluid dynamics of laminar
flow that utilizes a small amount of mineral oil at the beginning of sample injection to prevent air bubbles from occurring
in microchannels. We also further optimized the pressure, the length of the pressurizing channel and the volume of oil, thus
making our microfluidic device more useful for high-temperature PCR. Additionally, quantitative continuous-flow PCR was performed
using the optimized PCR chip in order to detect genetically modified (GM) maize. DNA was extracted from GM maize, MON 810,
and non-GM maize at several concentrations from 0% (w/v) to 100% (w/v). The DNA amplification signals were then analyzed on
the PCR chip using a laser-based system. The signal from our microfluidic PCR chip was found to increase in direct proportion
to the initial GM maize concentration. 相似文献