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排序方式: 共有114条查询结果,搜索用时 15 毫秒
61.
Influence of Fluorination on the Conformational Properties and Hydrogen‐Bond Acidity of Benzyl Alcohol Derivatives
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62.
Costanza Vanni Anne Bodlenner Marco Marradi Jrmy P. Schneider Maria de los Angeles Ramirez Sergio Moya Andrea Goti Francesca Cardona Philippe Compain Camilla Matassini 《Molecules (Basel, Switzerland)》2021,26(19)
Among carbohydrate-processing enzymes, Jack bean α-mannosidase (JBα-man) is the glycosidase with the best responsiveness to the multivalent presentation of iminosugar inhitopes. We report, in this work, the preparation of water dispersible gold nanoparticles simultaneously coated with the iminosugar deoxynojirimycin (DNJ) inhitope and simple monosaccharides (β-d-gluco- or α-d-mannosides). The display of DNJ at the gold surface has been modulated (i) by using an amphiphilic linker longer than the aliphatic chain used for the monosaccharides and (ii) by presenting the inhitope, not only in monomeric form, but also in a trimeric fashion through combination of a dendron approach with glyconanotechnology. The latter strategy resulted in a strong enhancement of the inhibitory activity towards JBα-man, with a Ki in the nanomolar range (Ki = 84 nM), i.e., more than three orders of magnitude higher than the monovalent reference compound. 相似文献
63.
An efficient access to 1,1-diarylethylenes of biological interest by coupling functionalized aryl Grignard reagents and 1-arylvinyl halides in the presence of FeCl(3)/CuTC is described. This bimetallic system proved to be superior to the use of Fe or Cu catalyst alone. The synthetic utility of this protocol is illustrated in the field of steroid chemistry. 相似文献
64.
JD Cafun J Lejeune F Baudelet P Dumas JP Itié A Bleuzen 《Angewandte Chemie (International ed. in English)》2012,51(36):9146-9148
In from the cold: The Co(III) Fe(II) state of a CoFe Prussian blue analogue undergoes a Co(III) ?Fe(II) →(Co(II) ?Fe(III) )* electron transfer at room temperature when irradiated by visible light (532?nm; see scheme). This property was confirmed using energy-dispersive X-ray absorption spectroscopy at the Co and Fe K-edges of the piezo-induced Co(III) Fe(II) state. 相似文献
65.
Narrowly distributed poly(N-vinyl caprolactam) obtained by the MADIX/RAFT process was used for the preparation of novel thermoresponsive gold nanoparticles presenting a sharp reversible response to temperature, which can be easily modulated near the physiological temperature by simply changing the polymer molecular weight or concentration. 相似文献
66.
Valerio Scarani Jean-Daniel Bancal Antoine Suarez Nicolas Gisin 《Foundations of Physics》2014,44(5):523-531
We discuss models that attempt to provide an explanation for the violation of Bell inequalities at a distance in terms of hidden influences. These models reproduce the quantum correlations in most situations, but are restricted to produce local correlations in some configurations. The argument presented in (Bancal et al. Nat Phys 8:867, 2012) applies to all of these models, which can thus be proved to allow for faster-than-light communication. In other words, the signalling character of these models cannot remain hidden. 相似文献
67.
Decroocq C Rodríguez-Lucena D Russo V Mena Barragán T Ortiz Mellet C Compain P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(49):13825-13831
In contrast to most lectins, glycosidases may appear to be unpromising targets for multivalent binding because they display only a single active site. To explore the potential of multivalency on glycosidase inhibition, unprecedented cyclodextrin-based iminosugar conjugates have been designed and prepared. The synthesis was performed by way of Cu(I) -catalyzed azide-alkyne cycloaddition reaction under microwave activation between propargylated multivalent β-cyclodextrins and an azide-armed N-alkyl 1-deoxynojirimycin derivative. Evaluation with a panel of glycosidases of this new class of glycomimetic clusters revealed the strongest affinity enhancement observed to date for a multivalent glycosidase inhibitor, with binding enhancement up to four orders of magnitude over the corresponding monovalent ligand for α-mannosidase. These results demonstrate that the multivalency concept extends beyond carbohydrate-lectin recognition processes to glycomimetic-enzyme inhibition. 相似文献
68.
Clara Fournier Jean-Daniel Marty Christian Bourgerette Alain Boudet Monique Mauzac 《Liquid crystals》2013,40(4):435-443
Ordered beads were obtained by the suspension copolymerization of amesogenic methacrylate-based monomer and methacrylic acid. The stability of these particles and the liquid crystal organization inside the particles depend mainly on the time of polymerization and on the crosslinking. Suspended droplets of monomers or polymers can be obtained as well as solid spheres. The solid particles exhibit ordered microstructures with a liquid crystal configuration that has a variable form depending on polymerization time and observation temperature. Bead characteristics such as morphology, size and polydispersity, and porosity are discussed and compared with those of non-mesomorphic beads. The mesomorphic beads are smaller and their porosity lower. The presence of a crosslinker during the polymerization process leads to more mechanically stable particles with retention of polymorphism. 相似文献
69.
Aldolic condensations with 0-ethyl thioesters are performed on basic alumina to give 2,3-unsaturated thioates. The stereochemistry of the reaction is discussed and compared with Knoevenagel's, Pinner's and Wittig-Horner's reactions. 相似文献
70.
The scope and limitations of a novel intramolecular azetidine ring-opening/closing cascade reaction affording spirocyclopropyl γ-lactams from azetidines in high regio- and stereoselectivity is reported. The key step of the process is a SN2-type ring-opening of TMSOTf-activated azetidine rings by silyl ketene acetals generated by treatment with TMSOTf and TEA. This study is a very rare example of nucleophilic ring-opening of azetidines that does not require formation of quaternary azetidinium salts by N-alkylation or the use of N-electron-withdrawing groups. Application of this process to 2-azetidinone system led to a complete change in reactivity and provide 6-aza-bicyclo[3.2.0]heptane derivatives via an unprecedented Mukaiyama aldol-like reaction involving an ester acceptor and a silyl imidate. 相似文献