Search results for "rafts"
showing 10 items of 228 documents
Reacciones de Friedel-Crafts enantioselectivas de naftoles, fenoles e hidroxiindoles catalizadas por derivados de alcaloides de la Cinchona
2016
Durante los últimos años, han sido descritos numerosos ejemplos de reacciones enantioselectivas con hidroxiarenos, especialmente usando organocatalizadores bifuncionales. A pesar de ello, la funcionalización asimétrica de hidroxiarenos ha sido menos estudiada si la comparamos con reacciones de Friedel-Crafts con indoles o pirroles. Además, el alcance de la reacción respecto del nucleófilo es limitado en muchos casos. En el capítulo 2.2, se describe una descripción detallada de todos las reacciones de Friedel-Crafts enantioselectivas con hidroxiarenos descritas en la bibliografía. En este contexto, durante la presente tesis hemos descrito el desarrollo de nuevos métodos para la funcionalizac…
The impact of tumor nitric oxide production on VEGFA expression and tumor growth in a zebrafish rat glioma xenograft model.
2015
International audience; To investigate the effect of nitric oxide on tumor development, we established a rat tumor xenograft model in zebrafish embryos. The injected tumor cells formed masses in which nitric oxide production could be detected by the use of the cell-permeant DAF-FM-DA (diaminofluorophore 4-amino-5-methylamino-2'-7'-difluorofluorescein diacetate) and DAR-4M-AM (diaminorhodamine-4M). This method revealed that nitric oxide production could be co-localized with the tumor xenograft in 46% of the embryos. In 85% of these embryos, tumors were vascularized and blood vessels were observed on day 4 post injection. Furthermore, we demonstrated by qRT-PCR that the transplanted glioma ce…
ChemInform Abstract: Enantioselective Synthesis of Substituted Indoles Through Zirconium(IV)-Catalyzed Friedel-Crafts Alkylation.
2013
The method allows the introduction of a C-3 side chain bearing a tertiary stereogenic center.
Highly Enantioselective Friedel−Crafts Alkylations of Indoles with Simple Enones Catalyzed by Zirconium(IV)−BINOL Complexes
2007
Complexes of BINOL-based ligands with Zr(OtBu)4 catalyze the Friedel-Crafts alkylation reaction of indoles and pyrrole with nonchelating beta-substituted alpha,beta-enones at room temperature affording the expected products with good yields and ee above 95% in most of the studied examples.
ChemInform Abstract: Enantioselective Synthesis of Tertiary Alcohols Through a Zirconium-Catalyzed Friedel-Crafts Alkylation of Pyrroles with α-Ketoe…
2011
Chiral complexes of 1,1′-bi-2-naphthol-based ligands with zirconium tert-butoxide catalyze the Friedel–Crafts alkylation of pyrroles with α-ketoesters to afford tertiary alcohols in good yields and ee up to 98%. The reaction is also of application to 4,7-dihydroindole to give C2-alkylated indoles after oxidation with p-benzoquinone.
Enantioselective Synthesis of Tertiary Alcohols through a Zirconium-Catalized Friedel-Crafts Alkylation of Pyrroles with alpha-Ketoesters
2011
Chiral complexes of 1,10-bi-2-naphthol-based ligands with zirconium tert-butoxide catalyze the Friedel Crafts alkylation of pyrroles with R-ketoesters to afford tertiary alcohols in good yields and ee up to 98%. The reaction is also of application to 4,7-dihydroindole to give C2-alkylated indoles after oxidation with p-benzoquinone.
ChemInform Abstract: Synthesis of Functionalized Indoles with a Trifluoromethyl-Substituted Stereogenic Tertiary Carbon Atom Through an Enantioselect…
2010
Chiral complexes of BINOL-based ligands with zirconium tert-butoxide catalyze the Friedel-Crafts alkylation reaction of indoles with beta-trifluoromethyl-alpha,beta-unsaturated ketones to give functionalized indoles with an asymmetric tertiary carbon center attached to a trifluoromethyl group. The reaction can be applied to a large number of substituted alpha-trifluoromethyl enones and substituted indoles. The expected products were obtained with good yields and ees of up to 99%.
Les radeaux membranaires et la signalisation végétale
2016
Face à une fluctuation des paramètres de son milieu ambiant ou à une agression biotique, la cellule végétale met en place une réponse adaptative dont les étapes les plus précoces sont la reconnaissance précise et rapide du stress, capable d’induire le développement d’une cascade de signalisation appropriée. Certains des acteurs de ces voies sont localisés sur la membrane plasmique (MP). En fonction de l’espèce, l’état physiologique… d’une cellule, on trouve au sein de sa MP des lipides, des protéines et des oses de structures et en concentrations variables. Chez les cellules de tabac, par exemple, on compte environ 50 lipides pour une protéine.Bien que moins nombreuses, les protéines ont po…
Plant lipid rafts : from proteic composition to physiological roles
2007
International audience; A large body of evidence supports the existence, in membrane from animal and yeast cells, of functional microdomains playing important roles in protein sorting, signal transduction, or infection by pathogens (1). We demonstrated the presence, in plants, of detergent resistant fractions isolated from plasma membrane, with a lipidic composition similar to animal microdomains (2). Electrophoresis experiments indicated that these fractions were able to recruit a specific set of plasma membrane proteins and exclude others. We used mass spectrometry to give an extensive description of a tobacco plasma membrane microdomains. This led to the identification of 145 proteins wh…
Nevers (Nièvre). Place Mossé, quai des Mariniers [notice archéologique]
2019
Les sondages archéologiques réalisés sur la place Mossé et à ses abords (quai des Mariniers et Tour Goguin) à Nevers, apportent des connaissances nouvelles sur cette partie du quartier bas des faïenciers.