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21.
Hikaru Yanai Takumi Suzuki Florian Kleemiss Haruhiko Fukaya Yasuo Dobashi Lorraine A. Malaspina Simon Grabowsky Takashi Matsumoto 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(26):8931-8936
1,1‐Diamino‐2,2‐bis(triflyl)ethylenes with both twisted and planar structures around the partial “C=C” bond were synthesised. Bonding properties in these compounds were analysed by an experimental approach using high‐resolution X‐ray diffraction data treated with X‐ray wavefunction refinement (XWR). In the twisted compound, a dominant contribution of the charge‐separated resonance structure was revealed. On the contrary, the nearly planar compound still showed π‐bonding character, however, with a considerable contribution of the charge‐separated resonance structure. 相似文献
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23.
Caldwell LM Hill AF Wagler J Willis AC 《Dalton transactions (Cambridge, England : 2003)》2008,(27):3538-3541
The first examples of isoselenocarbonyl linked bimetallics arise from the chemoselective insertion of platinum(0) into the alkynyl-selenium bond of a molybdenum alkynylselenolatoalkyidyne complex. 相似文献
24.
Ferrar L Mis M Dinnocenzo JP Farid S Merkel PB Robello DR 《The Journal of organic chemistry》2008,73(15):5683-5692
Photoinitiated triplet quantum amplified isomerizations (QAI) of substituted Dewar benzene derivatives in polymeric media are reported. The quantum efficiencies and the ultimate extents of reactant-to-product conversions increase significantly with the incorporation of appropriate co-sensitizers; compounds whose triplet energies are similar to or lower than that of the sensitizer and close to that of the reactant. These co-sensitizers serve to promote chain-propagating energy transfer processes and thereby increase the action sphere of photosensitization. Isomerization quantum yields increase, as predicted, with increasing concentrations of the reactants and the co-sensitizers. Chain amplifications as large as approximately 16 and extents of conversion that approach 100% have been achieved. Mechanistic schemes are proposed to account for the dynamics of the inherent energy transfer processes and provide a predictively useful model for the design of a new class of photoresponsive polymers based on changes in the refractive index of the materials. 相似文献
25.
Discovery of a Highly Selective Glycogen Synthase Kinase‐3 Inhibitor (PF‐04802367) That Modulates Tau Phosphorylation in the Brain: Translation for PET Neuroimaging
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Prof. Dr. Steven H. Liang Dr. Jinshan Michael Chen Prof. Dr. Marc D. Normandin Dr. Jeanne S. Chang Dr. George C. Chang Dr. Christine K. Taylor Dr. Patrick Trapa Dr. Mark S. Plummer Dr. Kimberly S. Para Dr. Edward L. Conn Dr. Lori Lopresti‐Morrow Dr. Lorraine F. Lanyon Dr. James M. Cook Dr. Karl E. G. Richter Dr. Charlie E. Nolan Dr. Joel B. Schachter Dr. Fouad Janat Dr. Ye Che Dr. Veerabahu Shanmugasundaram Dr. Bruce A. Lefker Dr. Bradley E. Enerson Prof. Dr. Elijahu Livni Lu Wang Dr. Nicolas J. Guehl Dr. Debasis Patnaik Florence F. Wagner Prof. Dr. Roy Perlis Dr. Edward B. Holson Prof. Dr. Stephen J. Haggarty Prof. Dr. Georges El Fakhri Dr. Ravi G. Kurumbail Prof. Dr. Neil Vasdev 《Angewandte Chemie (International ed. in English)》2016,55(33):9601-9605
Glycogen synthase kinase‐3 (GSK‐3) regulates multiple cellular processes in diabetes, oncology, and neurology. N‐(3‐(1H‐1,2,4‐triazol‐1‐yl)propyl)‐5‐(3‐chloro‐4‐methoxyphenyl)oxazole‐4‐carboxamide (PF‐04802367 or PF‐367) has been identified as a highly potent inhibitor, which is among the most selective antagonists of GSK‐3 to date. Its efficacy was demonstrated in modulation of tau phosphorylation in vitro and in vivo. Whereas the kinetics of PF‐367 binding in brain tissues are too fast for an effective therapeutic agent, the pharmacokinetic profile of PF‐367 is ideal for discovery of radiopharmaceuticals for GSK‐3 in the central nervous system. A 11C‐isotopologue of PF‐367 was synthesized and preliminary PET imaging studies in non‐human primates confirmed that we have overcome the two major obstacles for imaging GSK‐3, namely, reasonable brain permeability and displaceable binding. 相似文献
26.
John P. Smith III Lorraine M. Males Funda Gonulates 《Mathematical Thinking and Learning》2016,18(4):239-270
Research has found that elementary students face five main challenges in learning area measurement: (1) conserving area as a quantity, (2) understanding area units, (3) structuring rectangular space into composite units, (4) understanding area formulas, and (5) distinguishing area and perimeter. How well do elementary mathematics curricula address these challenges? A detailed analysis of three U.S. elementary textbook series revealed systematic deficits. Each presented area measurement in strongly procedural terms using a shared sequence of procedures across grades. Key conceptual principles were infrequently expressed and often well after related procedures were introduced. Particularly weak support was given for understanding how the multiplication of lengths produces area measures. The results suggest that the content of written curricula contributes to students’ weak learning of area measurement. 相似文献
27.
Cryogenic scanning electron microscopy (cryo-SEM) was used to investigate microstructure development of composite coatings prepared from dispersions of antimony-doped tin oxide (ATO) nanoparticles (approximately 30 nm) or indium tin oxide (ITO) nanoparticles (approximately 40 nm) and latex particles (polydisperse, D(v): approximately 300 nm). Cryo-SEM images of ATO/latex dispersions as-frozen show small clusters of ATO and individual latex particles homogeneously distribute in a frozen water matrix. In contrast, cryo-SEM images of ITO/latex dispersions as-frozen show ITO particles adsorb onto latex particle surfaces. Electrostatic repulsion between negatively charged ATO and negatively charged latex particles stabilizes the ATO/latex dispersion, whereas in ITO/latex dispersion, positively charged ITO particles are attracted onto surfaces of negatively charged latex particles. These results are consistent with calculations of interaction potentials from past research. Cryo-SEM images of frozen and fractured coatings reveal that both ceramic nanoparticles and latex become more concentrated as drying proceeds; larger latex particles consolidate with ceramic nanoparticles in the interstitial spaces. With more drying, compaction flattens the latex-latex particle contacts and shrinks the voids between them. Thus, ceramic nanoparticles are forced to pack closely in the interstitial spaces, forming an interconnected network. Finally, latex particles partially coalesce at their flattened contacts, thereby yielding a coherent coating. The research reveals how nanoparticles segregate and interconnect among latex particles during drying. 相似文献
28.
Pailloux S Binyamin I Deck LM Rapko BM Hay BP Duesler EN Paine RT 《The Journal of organic chemistry》2007,72(24):9195-9202
Synthetic routes to 2-(pyridin-2-yl)-N,N-diphenylacetamide and 2-(6-methylpyridin-2-yl)-N,N-diphenyl-acetamide are described along with results from the chemical oxidation of these compounds with peracetic acid, m-chloroperbenzoic acid, and OXONE. In each case, oxidations generate four products in varying amounts depending on the oxidant and reaction conditions. Each product has been characterized by spectroscopic methods and the molecular structures of several of the new compounds have been confirmed by X-ray crystallography. 相似文献
29.
Oxidation of 2-alkoxy-3,4-dihydro-2H-pyrans 3 with dimethyldioxirane or MTO/urea-H2O2 followed by Jones oxidation leads to rearrangement and stereocontrolled formation of 4,5-cis-disubstituted tetrahydrofuranones. The method is applied to the synthesis of the whisky lactone 9, cognac lactone 10 and crobarbatic acid 17. 相似文献
30.
The total syntheses of the 3,6-dihydroxydecanolide from Cordyceps militaris and the novel C-3 epimer are reported using a diastereoselective Nozaki-Hiyama-Kishi reaction in the key cyclization to generate the 6R stereocenter. 相似文献