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141.
Caitlin M. McMahon Prof. Erik J. Alexanian 《Angewandte Chemie (International ed. in English)》2014,53(23):5974-5977
A palladium‐catalyzed, intermolecular Heck‐type coupling of alkyl iodides and alkenes is described. This process is successful with a variety of primary and secondary unactivated alkyl iodides as reaction partners, including those with hydrogen atoms in the β position. The mild catalytic conditions enable intermolecular C? C bond formations with a diverse set of alkyl iodides and alkenes, including substrates containing base‐ or nucleophile‐sensitive functionality. 相似文献
142.
A Bioorthogonal Small‐Molecule‐Switch System for Controlling Protein Function in Live Cells
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Dr. Peng Liu Abram Calderon Dr. Georgios Konstantinidis Dr. Jian Hou Dipl. Stephanie Voss Dr. Xi Chen Fu Li Soumya Banerjee Dr. Jan‐Erik Hoffmann Christiane Theiss Dr. Leif Dehmelt Dr. Yao‐Wen Wu 《Angewandte Chemie (International ed. in English)》2014,53(38):10049-10055
Chemically induced dimerization (CID) has proven to be a powerful tool for modulating protein interactions. However, the traditional dimerizer rapamycin has limitations in certain in vivo applications because of its slow reversibility and its affinity for endogenous proteins. Described herein is a bioorthogonal system for rapidly reversible CID. A novel dimerizer with synthetic ligand of FKBP′ (SLF′) linked to trimethoprim (TMP). The SLF′ moiety binds to the F36V mutant of FK506‐binding protein (FKBP) and the TMP moiety binds to E. coli dihydrofolate reductase (eDHFR). SLF′‐TMP‐induced heterodimerization of FKBP(F36V) and eDHFR with a dissociation constant of 0.12 μM . Addition of TMP alone was sufficient to rapidly disrupt this heterodimerization. Two examples are presented to demonstrate that this system is an invaluable tool, which can be widely used to rapidly and reversibly control protein function in vivo. 相似文献
143.
144.
Pia Rönfeldt Helge Reinsch Erik Svensson Grape A. Ken Inge Huayna Terraschke Norbert Stock 《无机化学与普通化学杂志》2020,646(16):1373-1379
A new scandium naphthalenedicarboxylate with the framework composition [Sc2(1,4-NDC)3] (H2-1,4-NDC = 1,4-naphthalenedicarboxylic acid) was obtained under hydrothermal synthesis conditions. A structure model could be developed by a combination of 3D electron diffraction measurements and computationally assisted structure determination, which was further validated by a good agreement with the experimental powder X-ray diffraction pattern. The structure consists of isolated ScO6 octahedra interconnected by the carboxylate groups of linker molecules to form chains. These chains are connected by the naphthalene-moieties to form a three-dimensional framework with square-shaped pores and the organic group pointing into the pores. Although very similar synthesis conditions were chosen, [Sc2(1,4-NDC)3] is not isostructural to aluminum naphthalenedicarboxylate [Al(OH)(1,4-NDC)], which crystallizes in a MIL-53 type structure. This can be traced back to the different inorganic building units that are observed. The compound was thoroughly characterized by elemental analysis, IR spectroscopy, sorption measurements, thermogravimetric analysis and luminescence measurements. [Sc2(1,4-NDC)3] exhibits a high thermal stability and a ligand-based blue luminescence in the solid state at room temperature. 相似文献
145.
Felix Burkhardt Carl G. Schirmeister Christian Wesemann Massimo Nutini Stefano Pieralli Erik H. Licht Marc Metzger Frederik Wenz Rolf Mülhaupt Benedikt C. Spies 《Molecules (Basel, Switzerland)》2020,25(24)
A polyolefin with certified biocompatibility according to USP class VI was used by our group as feedstock for filament-based 3D printing to meet the highest medical standards in order to print personal protective equipment for our university hospital during the ongoing pandemic. Besides the chemical resistance and durability, as well as the ability to withstand steam sterilization, this polypropylene (PP) copolymer is characterized by its high purity, as achieved by highly efficient and selective catalytic polymerization. As the PP copolymer is suited to be printed with all common printers in fused filament fabrication (FFF), it offers an eco-friendly cost–benefit ratio, even for large-scale production. In addition, a digital workflow was established focusing on common desktop FFF printers in the medical sector. It comprises the simulation-based optimization of personalized print objects, considering the inherent material properties such as warping tendency, through to validation of the process chain by 3D scanning, sterilization, and biocompatibility analysis of the printed part. This combination of digital data processing and 3D printing with a sustainable and medically certified material showed great promise in establishing decentralized additive manufacturing in everyday hospital life to meet peaks in demand, supply bottlenecks, and enhanced personalized patient treatment. 相似文献
146.
Marco Deiana Karam Chand Jan Jamroskovic Ikenna Obi Erik Chorell Nasim Sabouri 《Angewandte Chemie (International ed. in English)》2020,59(2):896-902
The design of turn‐on dyes with optical signals sensitive to the formation of supramolecular structures provides fascinating and underexplored opportunities for G‐quadruplex (G4) DNA detection and characterization. Here, we show a new switching mechanism that relies on the recognition‐driven disaggregation (on‐signal) of an ultrabright coumarin‐quinazoline conjugate. The synthesized probe selectively lights‐up parallel G4 DNA structures via the disassembly of its supramolecular state, demonstrating outputs that are easily integrable into a label‐free molecular logic system. Finally, our molecule preferentially stains the G4‐rich nucleoli of cancer cells. 相似文献
147.
Erik Barwa Tobias F. Pascher Milan On
k Christian van der Linde Martin K. Beyer 《Angewandte Chemie (International ed. in English)》2020,59(19):7467-7471
We investigate activation of carbon dioxide by singly charged hydrated magnesium cations Mg .+(H2O)n, through infrared multiple photon dissociation (IRMPD) spectroscopy combined with quantum chemical calculations. The spectra of [MgCO2(H2O)n].+ in the 1250–4000 cm?1 region show a sharp transition from n=2 to n=3 for the position of the CO2 antisymmetric stretching mode. This is evidence for the activation of CO2 via charge transfer from Mg .+ to CO2 for n≥3, while smaller clusters feature linear CO2 coordinated end‐on to the metal center. Starting with n=5, we see a further conformational change, with CO2.? coordination to Mg2+ gradually shifting from bidentate to monodentate, consistent with preferential hexa‐coordination of Mg2+. Our results reveal in detail how hydration promotes CO2 activation by charge transfer at metal centers. 相似文献
148.
Klaus Gundertofte Tommy Liljefors Per-ola Norrby Ingrid Pettersson 《Journal of computational chemistry》1996,17(4):429-449
Several commonly used molecular mechanics force fields have been tested for accuracy in conformational energy calculations. Differences in performance between the force fields are discussed for different classes of structures. MMFF93 and force fields based on the MM2 or MM3 functional form are found to perform significantly better than other force fields in the test, with average conformational energy errors around 0.5 kcal/mol. CFF91 also reaches this accuracy for the subset in which fully determined parameters are used, but it doubles the overall error due to use of estimated parameters. Harmonic force fields generally have average errors exceeding 1 kcal/mol. Factors influencing accuracy are identified and discussed. © 1996 by John Wiley & Son s, Inc. 相似文献
149.
The elution order of the hop α- and β-acids has been studied under different modes of electrokinetic separation. A model is advanced to explain the shorter migration times of the more hydrophobic β-acids compared to the α-acids in micellar electrokinetic chromatography (MEKC). For quality control of the bitter principles in hops, the ruggedness of electrokinetic separation could be improved by replacing MEKC by microemulsion electrokinetic chromatography (MEEKC). 相似文献
150.
Cationic group 4 metal alkyl complexes containing tetradentate Schiff base ligands, (acen) Zr(R)+ and (F6-acen) Zr(R)+, are prepared by protonolysis of suitable neutral dialkyl precursors. These complexes display electrophilic behavior and are moderately active ethylene polymerization catalysts in the presence of 1 molar equivalent of AlR3. 相似文献