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121.
Use of capillary electrophoresis as a versatile tool to measure interaction constants between a KDR‐binding PEGylated lipopeptide and pegylated phospholipid micelles 下载免费PDF全文
In the frame of our molecular imaging activities, a PEGylated lipopeptide has been developed as a specific ligand for the human vascular endothelial growth factor receptor 2, which is considered as one of the important molecular marker of angiogenesis. In this study, the potential of affinity capillary electrophoresis (ACE) is evaluated to measure the interactions of an active PEGylated lipopeptide, its hydrolysis product and its precursor consisting of a peptide structure with different micelles including Brij‐35, Tween‐20, and pegylated phospholipids. Given the amphiphilic structure of the PEGylated lipopeptide, a MEKC method allowing the simultaneous separation of the compounds of interest was set up, using low percentages of acetonitrile. Analytes were resolved using a BGE consisting of 100 mM borate buffer pH 9.0, 1 mM Brij, and 25% acetonitrile. Optimized conditions were then used to perform ACE experiments. The affinity constants of the analytes with the micelles were calculated on the basis of their mobility decrease when surfactant concentration increased in the electrolyte. The use of different linearization models to estimate affinity constants was discussed and comparison of different surfactants was reported. PEGylated lipopeptide interacted more strongly with pegylated phospholipid micelles than with Brij‐35 or Tween‐20. Moreover, it is likely that the chemical structure of the compounds, and particularly the lipidic part of the molecules, significantly affects the interaction with micelles. In conclusion, the ACE method can be readily applied to investigate interactions of our targeting lipopeptides with various micelles currently used for the preparation of pharmaceutical vehicles. 相似文献
122.
Hammoud H Schmitt M Bihel F Antheaume C Bourguignon JJ 《The Journal of organic chemistry》2012,77(1):417-423
A modified Ullmann reaction using p-methoxybenzyl (PMB) guanidine as guanidinylation agent yielded various aryl and heteroaryl guanidines in good yields. 相似文献
123.
Martine Assié Abdelkrim Meddour Jean-Claude Fiaud Jean-Yves Legros 《Tetrahedron: Asymmetry》2010,21(13-14):1701-1708
Alkylation of racemic 1-(6-methoxynaphth-2-yl)ethyl acetate by potassium dimethyl malonate catalyzed by a chiral palladium-DUPHOS complex afforded the substitution product with 87% ee, along with 6-methoxy-2-vinylnaphthalene that arose from an elimination process, in a 43/57 substitution/elimination ratio. The reaction performed on a mixture of quasi-enantiomeric substrates provided insight into the stereochemical course of the reaction, establishing that—for a given enantiomer of the catalyst, one enantiomer of the substrate afforded mainly the substitution product whereas the other enantiomer underwent elimination. 相似文献
124.
Amandine Fabrello Chiara Dinoi Lionel Perrin Philippe Kalck Laurent Maron Martine Urrutigoity Odile Dechy‐Cabaret 《Magnetic resonance in chemistry : MRC》2010,48(11):848-856
103Rh NMR represents a powerful tool to assess the global electronic and steric contribution of diphosphine ligands on [Rh(COD)(diphosphine)]+ complexes. In the case of DIOP, BINAP and MeDUPHOS, this approach proved to be more informative than classical CO‐stretching frequency measurements. After validation, this method has been extended to a set of seven diphosphines. 103Rh NMR measurements on [Rh(COD)(diphosphine)]PF6 lead to the following order of donor properties: dppe > MeBPE > MeDUPHOS > dppb > DIOP > BINAP > Tol‐BINAP. This trend has been validated by DFT in the case of DIOP, BINAP and MeDUPHOS. In conjunction, 31P NMR chemical shift has been shown to reflect the ring constraints of the Rh‐diphosphine scaffold. This contribution is a step towards a mechanistic investigation of the catalytic hydrogenation of unsaturated substrates by 103Rh NMR and DFT. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
125.
[reaction: see text] Acid-catalyzed nucleophilic substitution of bicyclic hydrazine-epoxide involves nitrogen participation, leading to a skeletal rearrangement. This transformation enables the fast preparation of disubstituted bicyclic hydrazines in a regio- and stereoselective manner, leading to several polyfunctional diaminocyclopentanes after hydrogenolysis. 相似文献
126.
Pietro Belotti Martine Labbé Francesco Maffioli Malick M. Ndiaye 《4OR: A Quarterly Journal of Operations Research》2007,5(4):299-314
The obnoxious p-median (OpM) problem is the repulsive counterpart of the ore known attractive p-median problem. Given a set I of cities and a set J of possible locations for obnoxious plants, a p-cardinality subset Q of J is sought, such that the sum of the distances between each city of I and the nearest obnoxious site in Q is maximised. We formulate (OpM) as a {0,1} linear programming problem and propose three families of valid inequalities whose separation problem is polynomial.
We describe a branch-and-cut approach based on these inequalities and apply it to a set of instances found in the location
literature. The computational results presented show the effectiveness of these inequalities for (OpM).
The work of the first author has been partially supported by the Coordinated Project C.A.M.P.O. and that of the third author
by a short mobility grant, both of the Italian National Research Council. 相似文献
127.
Some recent results of Ayache on going-down domains and extensions of domains that either are residually algebraic or have DCC on intermediate rings are generalized to the context of extensions of commutative rings. Given a finite maximal chain 𝒞 of R-subalgebras of a weak Baer ring T, it is shown how a “min morphism” hypothesis can be used to transfer the “going-down ring” property from R to each member of 𝒞. The integral minimal ring extensions which are min morphisms are classified. The ring extensions satisfying FCP (i.e., for which each chain of intermediate rings is finite) are characterized as the strongly affine extensions with DCC on intermediate rings. In the relatively integrally closed case, such extensions R ? T induce open immersions Spec(S) → Spec(R) for each R-subalgebra S of T. 相似文献
128.
Pierre Thury Zouhair Asfari Martine Nierlich Jacques Vicens 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(4):o223-o225
Two complexes between mono‐deprotonated calix[4]arene and Et3HN+ are reported. The first, triethylammonium 26,27,28‐trihydroxypentacyclo[19.3.1.13,7.19,13.115,19]octacosa‐1(25),3,5,7(28),9,11,13(27),15,17,19(26),21,23‐dodecaen‐25‐olate, C6H16N+·C28H23O4?, comprises only the cationic and anionic species, whereas the second, tris(triethylammonium) tris[26,27,28‐trihydroxypentacyclo[19.3.1.13,7.19,13.115,19]octacosa‐1(25),3,5,7(28),9,11,13(27),15,17,19(26),21,23‐dodecaen‐25‐olate] acetonitrile solvate, 3C6H16N+·3C28H23O4?·C2H3N, comprises one acetonitrile solvent molecule for three such units. In both cases, the units are stacked in columns so that the ammonium cation is hydrogen bonded to a phenolic or phenolate O atom of one molecule and included in the hydrophobic cavity of another neighbouring calixarene. The short contacts present indicate that cation?π and C—H?π interactions are likely to be involved in the inclusion phenomena. 相似文献
129.
Luna AP Bonin M Micouin L Husson HP 《Journal of the American Chemical Society》2002,124(41):12098-12099
The Ir-catalyzed asymmetric hydroboration of bicyclic hydrazines with ee and chemical yields up to 64% is reported. The switch from rhodium to iridium leads systematically to opposite enantiomers in this desymmetrization reaction. 相似文献
130.
Anne-Solenn Le Hô Martine Regert Olivier Marescot Chloé Duhamel Juliette Langlois Tetsuo Miyakoshi Christophe Genty Michel Sablier 《Analytica chimica acta》2012
This paper focuses on the identification of several chemical markers of vegetal species of Oriental lacquers with the aim at providing a methodology consistent with sampling restrictions necessarily applied in the field of cultural heritage. The method proposed is based on rapid and easy single step thermally assisted hydrolysis–methylation (THM) pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) analysis that can be carried out with a minimum amount of matter (typically 10 μg for a sample collected on a museum or an archaeological object). 相似文献