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61.
Fluorous quaternary ammonium and phosphonium salts, as well as fluorous macrocyclic ligands, such as crown and aza-crown ethers, have been gradually emerging as viable alternatives to classical phase transfer catalysts. The major results thus far obtained in this burgeoning field will be the focus of this review. 相似文献
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Concetta De Stefano Antonio Gianguzza Ottavia Giuffr Alberto Pettignano Silvio Sammartano 《应用有机金属化学》2008,22(1):30-38
Thermodynamic data of mono‐, di‐ and tri‐methyltin(IV)‐carboxylate complexes (acetate, malonate, succinate, oxydiacetate, diethylenetrioxydiacetate, malate, citrate, 1,2,3‐tricarballylate, 1,2,3,4‐butanetetracarboxylate, 1,2,3,4,5,6‐benzenehexacarboxylate) in aqueous solution are reported at t = 25 °C and I = 0 mol l−1. Thermodynamic parameters obtained were analysed to formulate empirical predictive relationships as a function of different parameters, such as the number of carboxylate groups of the ligand and the charge of the alkyltin(IV) cation. Sequestration diagrams of citrate and 1,2,3‐tricarballylate towards alkyltin(IV) cations at different pH values are also reported and discussed. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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New five-ring hockey-stick liquid crystalline materials with 4-bromoresorcinol as the central core unit and an azobenzene-based side arm were synthesised and their mesophase behaviour was investigated by polarising optical microscopy, differential scanning calorimetry, X-ray diffraction and under a triangular wave electric field. Additional structural modification was done by introducing a lateral fluorine atom in the terminal ring of one of the side arms. It is found that regardless of the alkyl chain length or the lateral fluorine substitution, all of the prepared materials are liquid crystalline exhibiting nematic phases composed of cybotactic clusters of the SmC-type (NCybC) in addition to a monotropic SmC phase for the longest homologue. 相似文献
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Erika Cerutti Annelaure Damont Frédéric Dollé Simona Baroni Silvio Aime 《Magnetic resonance in chemistry : MRC》2013,51(2):116-122
DPA‐713 is the lead compound of a recently reported pyrazolo[1,5‐a]pyrimidineacetamide series, targeting the translocator protein (TSPO 18 kDa), and as such, this structure, as well as closely related derivatives, have been already successfully used as positron emission tomography radioligands. On the basis of the pharmacological core of this ligands series, a new magnetic resonance imaging probe, coded DPA‐C6‐(Gd)DOTAMA was designed and successfully synthesized in six steps and 13% overall yield from DPA‐713. The Gd‐DOTA monoamide cage (DOTA = 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid) represents the magnetic resonance imaging reporter, which is spaced from the phenylpyrazolo[1,5‐a]pyrimidineacetamide moiety (DPA‐713 motif) by a six carbon‐atom chain. DPA‐C6‐(Gd)DOTAMA relaxometric characterization showed the typical behavior of a small‐sized molecule (relaxivity value: 6.02 mM?1 s?1 at 20 MHz). The good hydrophilicity of the metal chelate makes DPA‐C6‐(Gd)DOTAMA soluble in water, affecting thus its biodistribution with respect to the parent lipophilic DPA‐713 molecule. For this reason, it was deemed of interest to load the probe to a large carrier in order to increase its residence lifetime in blood. Whereas DPA‐C6‐(Gd)DOTAMA binds to serum albumin with a low affinity constant, it can be entrapped into liposomes (both in the membrane and in the inner aqueous cavity). The stability of the supramolecular adduct formed by the Gd‐complex and liposomes was assessed by a competition test with albumin. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Silvano Ellena Alessandra Viale Roberto Gobetto Silvio Aime 《Magnetic resonance in chemistry : MRC》2012,50(8):529-533
Para‐hydrogen–induced polarization effects have been observed in the 29Si NMR spectra of trimethylsilyl para‐hydrogenated molecules. The high signal enhancements and the long T1 values observed for the 29Si hyperpolarized resonances point toward the possibility of using 29Si for hyperpolarization applications. A method for the discrimination of multiple compounds and/or complex mixtures of hydroxylic compounds (such as steroids), consisting of the silylization of alcoholic functionalities with an unsaturated silylalkyl moiety and subsequent reaction with para‐H2, is proposed. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Nannocystin A: an Elongation Factor 1 Inhibitor from Myxobacteria with Differential Anti‐Cancer Properties
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Philipp Krastel Silvio Roggo Markus Schirle Nathan T. Ross Francesca Perruccio Peter Aspesi Jr. Thomas Aust Kathrin Buntin David Estoppey Brigitta Liechty Felipa Mapa Klaus Memmert Howard Miller Xuewen Pan Ralph Riedl Christian Thibaut Jason Thomas Trixie Wagner Eric Weber Xiaobing Xie Esther K. Schmitt Dr. Dominic Hoepfner 《Angewandte Chemie (International ed. in English)》2015,54(35):10149-10154
Cultivation of myxobacteria of the Nannocystis genus led to the isolation and structure elucidation of a class of novel cyclic lactone inhibitors of elongation factor 1. Whole genome sequence analysis and annotation enabled identification of the putative biosynthetic cluster and synthesis process. In biological assays the compounds displayed anti‐fungal and cytotoxic activity. Combined genetic and proteomic approaches identified the eukaryotic translation elongation factor 1α (EF‐1α) as the primary target for this compound class. Nannocystin A ( 1 ) displayed differential activity across various cancer cell lines and EEF1A1 expression levels appear to be the main differentiating factor. Biochemical and genetic evidence support an overlapping binding site of 1 with the anti‐cancer compound didemnin B on EF‐1α. This myxobacterial chemotype thus offers an interesting starting point for further investigations of the potential of therapeutics targeting elongation factor 1. 相似文献