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51.
Francesca Cardona Andrea Goti Sylviane Picasso Pierre Vogel Alberto Brandi 《Journal of carbohydrate chemistry》2013,32(4-5):585-601
ABSTRACT (+)-Lentiginosine (14) and (7R)-7-hydroxylentiginosine (26), powerful inhibitors of amyloglucosidases, and their enantiomers were obtained in high overall yields by a multistep synthesis involving 1,3-dipolar cycloaddition of enantiopure tartaric acid derived pyrroline N-oxides. Structurally related (S,S)-3,4-dihydroxypyrrolidines 29-33 were synthesized as simpler models and tested towards 24 glycosidases. 相似文献
52.
Gloaguen Y Alcaraz G Petit AS Clot E Coppel Y Vendier L Sabo-Etienne S 《Journal of the American Chemical Society》2011,133(43):17232-17238
The reactivity of the (o-phosphinophenyl)(amino)borane compound HB(N(i)Pr(2))C(6)H(4)(o-PPh(2)) prepared from Li(C(6)H(4))PPh(2) and HBCl(N(i)Pr(2)) toward the bis(dihydrogen) complex RuH(2)(H(2))(2)(PCy(3))(2) (1) was studied by a combination of DFT, X-ray, and multinuclear NMR techniques including solid-state NMR, a technique rarely employed in organometallic chemistry. The study showed that the complex RuH(2){HB(N(i)Pr(2))C(6)H(4)(o-PPh(2))}(PCy(3))(2) (3), isolated in excellent yield as yellow crystals and characterized by X-ray diffraction, led in solution to PCy(3) dissociation and formation of an unsaturated 16-electron complex RuH(2){HB(N(i)Pr(2))C(6)H(4)(o-PPh(2))}(PCy(3)) (4), with a hydride trans to a vacant site. In both cases, the (phosphinoaryl)(amino)borane acts as a bifunctional ligand through the phosphine moiety and a Ru-H-B interaction, thus featuring an agostic interaction. 相似文献
53.
Bénac-Lestrille G Helmstedt U Vendier L Alcaraz G Clot E Sabo-Etienne S 《Inorganic chemistry》2011,50(21):11039-11045
The reaction of cyclodiborazane [Me(2)N-BH(2)](2) with the chloro(dihydrogen) ruthenium complex RuHCl(η(2)-H(2))(P(i)Pr(3))(2) (1) led to the formation of the unsymmetricaly coordinated dimethylaminoborane complex RuHCl(H(2)BNMe(2))(P(i)Pr(3))(2) (2). The dimethylaminoborane coordination (H(2)BNMe(2)) to the ruthenium center in 2 was carefully studied by combining X-ray, multinuclear NMR, and density functional theory (DFT) techniques, and compared with the recently reported osmium analogue which was originally formulated as a σ-B-H borinium complex [OsH(2)Cl(HBNMe(2))(P(i)Pr(3))(2)] (4). All our data are in favor of a bis(σ-B-H) coordination mode at a very activated stage in the case of the ruthenium complex 2, whereas in the osmium complex 4, full oxidative addition is favored leading to a complex better formulated as an osmium(IV) boryl species with an α-agostic B-H interaction. The synthesis and characterization of the symmetrical dihydride complex RuH(2)(H(2)BNMe(2))(P(i)Pr(3))(2) (3) from addition of the lithium dimethylaminoborohydride to 1 is reported for comparison. 相似文献
54.
Audrey Cassen Yann Gloaguen Laure Vendier Carine Duhayon Amalia Poblador‐Bahamonde Christophe Raynaud Eric Clot Gilles Alcaraz Sylviane Sabo‐Etienne 《Angewandte Chemie (International ed. in English)》2014,53(29):7569-7573
Tuning the nature of the linker in a L~BHR phosphinoborane compound led to the isolation of a ruthenium complex stabilized by two adjacent, δ‐C? H and ε‐Bsp2? H, agostic interactions. Such a unique coordination mode stabilizes a 14‐electron “RuH2P2” fragment through connected σ‐bonds of different polarity, and affords selective B? H, C? H, and B? C bond activation as illustrated by reactivity studies with H2 and boranes. 相似文献
55.
Delphine Gallois-Montbrun Nicolas Thiebault Vincent Moreau Geneviève Le Bas Jean-Christophe Archambault Sylviane Lesieur Florence Djedaïni-Pilard 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):131-135
A novel amphiphilic cyclodextrin derivative was obtained by controlled esterification of lauric acid chloride on the primary
face of the native β-cyclodextrin in a one step synthesis. The characterization of the substitution degree and isomer structure
was performed by mass and NMR spectroscopies. A specific purification procedure by sublimation was developed in order to eliminate
the excess of lauric acid molecules in the reaction product. The sublimation efficiency was assessed by differential scanning
calorimetry (DSC) in quantifying the remaining fatty acid. In this way the duration of the sublimation process could be optimized. 相似文献
56.
Sylviane R Schwer 《Comptes Rendus Mathematique》2002,334(4):261-266
We study natural correspondances between the set of arrangements of subsets with repetitions and families of objects met in various areas of mathematics (walks in lattices, pre-order) and computer science (formal languages, Petri nets, Artificial Intelligence), using the framework of formal languages. For n=2, they are enumerated by Delannoy numbers. To cite this article: S.R. Schwer, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 261–266. 相似文献
57.
58.
[reaction: see text] A 4-methyl-5-oxo docetaxel analogue has been prepared starting from 10-deacetylbaccatin III. This new D-seco docetaxel analogue is slightly less potent than docetaxel at microtubule stabilization in vitro and has about 1/1000th the cytotoxicity of docetaxel. The lack of improved activity for this compound compared to other D-modified taxoids confirms that a C-5 oxygen atom is not required for biological activity. 相似文献
59.
Godin JP Richelle M Metairon S Fay LB 《Rapid communications in mass spectrometry : RCM》2004,18(3):325-330
This paper validates the use of high-temperature conversion elemental analyser isotope-ratio mass spectrometry (TC-EA/IRMS) for measuring the [(2)H/H] enrichment of plasma [(2)H(5)]cholesterol. From a molecular point of view, the free cholesterol is initially separated from plasma by thin-layer chromatography (TLC) and then injected onto the TC-EA reactor which converts cholesterol molecules into CO and H(2) gases. The slope of the curve of the experimental mole percent excess (MPE((exp.))) versus MPE((theor.)) was very close to 1, demonstrating that no significant isotopic fractionation was observed during all processing of the samples (i.e., isolation of plasma free cholesterol by TLC and pyrolysis in the TC-EA reactor). Excellent linearity (r(2) = 0.9994, n = 4) of delta ( per thousand ) of [(2)H/H] isotopic measurements versus mole percent (MP) was assessed over the range 0 to 0.1 MP. The precision of the [(2)H/H] measurement, evaluated with two calibration points processed with TLC, was delta(2)H(V-SMOW) = -192.5 +/- 3.4 per thousand and delta(2)H(V-SMOW) = -136.9 +/- 2.9 per thousand. The standard deviations of the within-assay and between-assay repeatabilities of the analytical process, evaluated using the quality control (QC) of plasma samples, were 4.6 and 6.1 per thousand, respectively. Plant sterols are known to reduce cholesterol absorption and therefore were used as a positive control in a clinical study performed with normocholesterolemic volunteers. This present method produces biological results consistent with those already reported in the literature. 相似文献
60.
Lachaize S Sabo-Etienne S Donnadieu B Chaudret B 《Chemical communications (Cambridge, England)》2003,(2):214-215
Silylation of ethylene by chlorosilanes is catalysed by ruthenium complexes. Mechanistic investigations reveal the presence of a complicated network of reactions leading to new sigma-silane, ethylene and silyl complexes. 相似文献