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81.
Oxazolinethiones and oxazolidinethiones for the first copper-catalyzed desulfurative cross-coupling reaction and first sonogashira applications 总被引:1,自引:0,他引:1
Cyclic thionocarbamates, namely chiral oxazolidinethiones (OZT) and aromatic oxazolinethiones (OXT), were involved, for the first time, in Sonogashira cross-coupling. A cooperative effect of two different copper (I) species-CuI and CuTC-accounts for this new copper-catalyzed desulfurative carbon-carbon cross-coupling reaction. This cooperative reactivity could also be extended to other copper (I) catalysts. 相似文献
82.
(+)-MK7607 is a patented naturally occurring unsaturated pseudo-carbasugar possessing herbicidal activity. We present herein the first synthesis of the 5-fluorinated analogue (1S, 2S, 3R, 4R)-5-fluoro-6-(hydroxymethyl)cyclohex-5-ene-1,2,3,4-tetrol as well as that of two related compounds, namely its 1-epimer and its 6-deoxy derivative. 相似文献
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La-Torre-Riveros Lyda Doménech-Carbó Antonio Cabrera Carlos R. Doménech-Carbó María Teresa Huahuasoncco-Condori Wilber Quispe Guzmán Dino Gutiérrez-Castillo María del Carmen Carmona-Ochoa Katia Pérez-Trujillo Amelia 《Journal of Solid State Electrochemistry》2019,23(5):1541-1552
Journal of Solid State Electrochemistry - A series of sherds from the archeological site of Qotakalli in the area of Cusco (Perú), corresponding to four different Inka periods, were studied by... 相似文献
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Jesús-Mario Bilbao 《International Journal of Game Theory》1998,27(1):131-145
Games with cooperation structure are cooperative games with a family offeasible coalitions, that describes which coalitions can negotiate in the game. We study a model ofcooperation structure and the corresponding restricted game, in which the feasible coalitions are those belonging to apartition system. First, we study a recursive procedure for computing the Hart and Mas-Colell potential of these games and we develop the relation between the dividends of Harsanyi in the restricted game and the worths in the original game. The properties ofpartition convex geometries are used to obtain formulas for theShapley andBanzhaf values of the players in the restricted game in terms of the original gamev. Finally, we consider the Owen multilinear extension for the restricted game.The author is grateful to Paul Edelman, Ulrich Faigle and the referees for their comments and suggestions. The proof of Theorem 1 was proposed by the associate editor's referee. 相似文献
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Gregianini TS da Silveira VC Porto DD Kerber VA Henriques AT Fett-Neto AG 《Photochemistry and photobiology》2003,78(5):470-474
The effects of ultraviolet (UV) radiation on chlorophyll content and accumulation of the anti-inflammatory monoterpene-indole alkaloid brachycerine in plants and calli of Psychotria brachyceras (Rubiaceae) were investigated. In this study, we also investigated a protective role for brachycerine against stress conditions. Calli and tip cuttings incubated in nutrient media were daily supplemented with 4 or 16 h of UV. High-performance liquid chromatography analyses of methanolic extracts showed only traces of brachycerine in irradiated aseptic cultures, with no alkaloid being observed in control calli. In cuttings, a 10-fold increase in brachycerine content was seen after exposure for 16 h to UV-C, whereas a 4 h daily supplementation doubled the amount of the alkaloid in leaves. Exposure to a UV-B source also doubled the alkaloid yield. In vitro brachycerine was able to quench singlet oxygen. The data indicate a potential protective role for brachycerine against UV radiation, acting as a UV filter (absorption peaks are within the UV range) and a reactive oxygen species scavenger. In addition, UV radiation may be used to increase yields of this compound of pharmaceutical interest. 相似文献