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991.
992.
H Matsunaga M Katano H Yamamoto H Fujito M Mori K Takata 《Chemical & pharmaceutical bulletin》1990,38(12):3480-3482
The effects of the three polyacetylene compounds, panaxynol, panaxydol and panaxytriol, on in vitro-cell growth were studied. These compounds are much different in their water-solubility. In order to increase water-solubility, solid complexes of polyacetylene compounds with alpha-cyclodextrin (CD) were prepared. Accurate concentrations of the active compounds in a culture medium were determined by gas chromatography. All of these CD-complexes inhibited the growth of various kinds of cultured cell lines in a dose-dependent fashion. The cell growth inhibitory activity of these complexes was much stronger against malignant cells than against normal cells. A continuous contact between the compounds and target cells was not necessarily required for growth inhibition. And the inhibition was cytotoxic at high concentrations and cytostatic at low concentrations. These findings indicate that these polyacetylene compounds' mode of action is more dose-dependent than time-dependent. The panaxynol, panaxydol and panaxytriol contents in red ginseng powder were 250, 297 and 320 micrograms/g, respectively. 相似文献
993.
Masashi Gotoh Kazuhide Mori Reikichi Itoh 《International journal of quantum chemistry》1995,56(3):163-173
An automated method by the algebraic programming language REDUCE3 for specifying the matrix elements expressed in second quantization language is presented and then applied to the case of the matrix elements in the TDHF theory. This program works in a very straightforward way by commuting the electron creation and annihilation operators (a? and a) until these operators have completely vanished from the expression of the matrix element under the appropriate elimination conditions. An improved method using singlet generators of unitary transformations in the place of the electron creation and annihilation operators is also presented. This improvement reduces the time and memory required for the calculation. These methods will make programming in the field of quantum chemistry much easier. © 1995 John Wiley & Sons, Inc. 相似文献
994.
Daisuke Mori Atsuo Yamada Masaki Azuma Katsumi Suda 《Journal of solid state chemistry》2006,179(3):935-940
Single crystals of the thallium ruthenium pyrochlore have been grown by flux method under high oxygen pressure. The growth conditions were determined by direct observations using in situ powder X-ray diffraction (XRD) method under high pressure and high temperature. The crystals were grown using NaCl-KCl flux at 1350 °C and B2O3 flux at 1150 °C. High growth temperature of 1350 °C for the NaCl-KCl flux caused Pt contamination from the crucible and oxygen deficiency for the crystals obtained. The crystal growth using B2O3 flux proceeded at lower temperature by grain growth with material transfer through B2O3. The crystal obtained was characterized by single-crystal XRD method, and was found to have a stoichiometric composition, Tl2Ru2O7−δ (δ=0), with a structural phase transition around 120 K. The grain growth technique with B2O3 is efficient for high-temperature single-crystal growth under high pressure. 相似文献
995.
Nakatsuji S Ikemoto H Akutsu H Yamada J Mori A 《The Journal of organic chemistry》2003,68(5):1708-1714
Series of aminoxyl radicals (TEMPO or nitronyl nitroxide radicals) bearing phenyl benzoate, troponoid, or biphenylcarbonitrile as mesogenic cores with long alkyl substituents were prepared. Although most aminoxyl radicals showed only weak antiferromagnetic interactions due probably to the remote spin centers as clarified by the X-ray analysis of 4a and no appreciable mesogenic phase was observed in each compound, an unusual magnetic transition from an original Curie-Weiss phase to another magnetic phase well-expressed by a singlet-triplet (ST) model was disclosed through the thermal transition in the 4'-undecyloxy-4-biphenylcarbonitrile derivative with oxocarbonyl-TEMPO 12b. 相似文献
996.
The both enantiomers of (Z)-14-methylhexadec-8-enal were synthesized starting from (R)-(+)-citronellol. The (R)-(?)enantiomer (1) was about 250 times more active than its antipode (1') when tested on dermestid beetle. 相似文献
997.
A practical synthesis of (+)-biotin from L-cysteine 总被引:1,自引:0,他引:1
Seki M Hatsuda M Mori Y Yoshida S Yamada S Shimizu T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(23):6102-6110
Alpha-amino aldehyde 4, which is readily derived from L-cysteine through cyclization and elaboration of the carboxy group, was subjected to the Strecker reaction, which, via sodium bisulfite adduct 16, afforded alpha-amino nitrile 5 with high diastereoselectivity (syn/anti=11:1) and in high yield. Amide 6, derived from 5, was converted to thiolactone 8, a key intermediate in the synthesis of (+)-biotin (1), by a novel S,N-carbonyl migration and cyclization reaction. The Fukuyama coupling reaction of 8 with the zinc reagent 21, which has an ester group, in the presence of a heterogeneous Pd/C catalyst allowed the efficient installation of the 4-carboxybutyl chain to provide 9. Compound 9 was hydrogenated and the protecting groups removed to furnish 1 in 10 steps and in 34 % overall yield from L-cysteine. 相似文献
998.
H. Matsumoto H. Uchida H. Yoneyama T. Sakata H. Mori 《Research on Chemical Intermediates》1994,20(7):723-733
Gallium arsenide nanocrystals of 1.5 to 9.0 nm were prepared in triethylene glycol dimethylether (triglyme), and photoinduced
reduction of methylviologen (MV2+) on the nanocrystals was investigated. The rate of MV+ production determined for an initial stage of photoinduced reduction
of MV2+ was found to be low compared to that determined for bulk GaAs particles of 0.4 mm, if the rate was evaluated for unit surface
area of the semiconductor particles. To account for this finding, the apparent association constant of MV2+ to GaAs was determined, which suggested that molecular species which worked as stabilizing agents for the GaAs nanocrystals
retarded the adsorption of MV2+ onto the particle surfaces. 相似文献
999.
Nakamura M Mori Y Okuyama K Tanikawa K Yasuda S Hanada K Kobayashi S 《Organic & biomolecular chemistry》2003,1(19):3362-3376
Large-scale synthesis, design, and structure-activity relationships of khafrefungin are reported. Khafrefungin is an antifungal agent that inhibits inositol phosphorylceramide (IPC) synthase, an enzyme involved in fungal sphingolipid biosynthesis. Unlike other inhibitors that inhibit the corresponding enzyme in fungi and mammals to the same extent, khafrefungin does not impair sphingolipid synthesis in mammals. We have developed an efficient method for large-scale synthesis of khafrefungin, and various khafrefungin derivatives were synthesized based on this method. While most of the khafrefungin derivatives lost antifungal activity, a lactone-type derivative had almost the same activity as khafrefungin. We also designed and synthesized derivatives which contain a five- or six-membered ring at the central part of the structure based on NOE experiments of khafrefungin. A macrocyclic khafrefungin derivative was also synthesized, but the antifungal activity was lost. These results suggest that the structure of khafrefungin might be strictly recognized in fungi. 相似文献
1000.
Simultaneous use of N-hydroxysuccinimide (HOSu) and CuCl2 with a HOSu-based uronium coupling reagent, O-(N-succinimidyl)-1,1,3,3-tetramethyluronium tetrafluoroborate, has been found to eliminate the racemization of the carboxy-terminal N-methylamino acid residue during the segment condensation. 相似文献