Kristin Douty 《Magnetic resonance in chemistry : MRC》2016,54(10):782-786

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Patrick Zimdars;Kristin Böhlig;Peter Metz; 《European journal of organic chemistry》2019,2019(36):6163-6167

We report a study on diol cleavage of cyclic 1,2-dihydroxysilanes for the preparation of functionalized acylsilanes. Sodium periodate turned out to be an efficient reagent for this transformation, resulting in good to excellent yields. The method is characterized by mild reaction conditions, and sometimes simple aqueous workup of the reaction mixture was sufficient to obtain the acylsilanes in high purity. An acyclic 1,2-dihydroxysilane was readily cleaved as well.  相似文献   

    

Molly Reinmuth;Subhamay Pramanik;Justin T. Douglas;Victor W. Day;Kristin Bowman-James; 《欧洲无机化学杂志》2019,2019(14):1870-1874

An important biomolecule found in plant seeds and tissues, and in eukaryotic cells is myo-inositol-1,2,3,4,5,6-hexakisphosphate (phytate, IP6). Phytate has many roles, including phosphate, myo-inositol, and mineral storage and retrieval in plants, and a number of metabolic roles, not all of which are known. Despite the importance of phytate in biology, structural information is limited. Aside from this report of the potassium phytate structure, K3[H9IP6]·2H2O, only the structures of the sodium and zinc salts have appeared. The potassium structure reveals the importance of metal ion chelation in stabilizing the conformation, and the two previously reported structures support this finding. Potassium ion and hydrogen bond bridges link the interwoven phytate networks throughout the lattice. 1H NMR (800 MHz) titrations show the conformation crossover from the 1a5e to the 5a1e conformation between pH 9 and 10, and detailed 1H deconvolution studies at low pH reveal the underlying pattern assignments for individual protons.  相似文献   

    

Kristin Schacht  Tomasz Jüngst  Matthias Schweinlin  Andrea Ewald  Jürgen Groll  Thomas Scheibel 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(9):2858-2862

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Marie‐Kristin Lemke  Pia Schwab  Petra Fischer  Sandra Tischer  Morris Witt  Laurence Noehringer  Victor Rogachev  Anne Jger  Olga Kataeva  Roland Frhlich  Peter Metz 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2013,125(44):11865-11869

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Mirka‐Kristin Verhoefen  Karsten Neumann  Ingrid Weber  Clemens Glaubitz  Josef Wachtveitl 《Photochemistry and photobiology》2009,85(2):540-546

Femtosecond time‐resolved spectroscopy in the visible and IR range was utilized to study the primary reaction dynamics of the proteorhodopsin (PR) D97N mutant in comparison with wild type PR at different pH values. The analysis of the data obtained in the mid‐IR closely resembles the results for wild type PR. The observation of the first ground state intermediate K is initially obscured by a complex reaction scheme of vibrational relaxation and heating effects, but its spectral signature clearly emerges at long delay times. In the visible range, a biexponential decay of the excited state within 30 ps and the formation of the K photoproduct is observed. The decay time constants derived for the D97N mutant in D₂O are slightly larger than in H₂O due to H/D exchange. This kinetic isotope effect is even less pronounced than for wild type PR at pH 6. These results support the current notion of a pH dependent hydrogen bonding network in the retinal binding pocket of PR and a weaker interaction between the retinal Schiff base and the counter ion complex compared to bacteriorhodopsin.  相似文献   

Divergent Synthesis of a Pochonin Library Targeting HSP90 and In Vivo Efficacy of an Identified Inhibitor     

Sofia Barluenga Dr.  Cuihua Wang Dr.  Jean-Gonzague Fontaine  Kaïss Aouadi Dr.  Kristin Beebe  Shinji Tsutsumi Dr.  Len Neckers Dr.  Nicolas Winssinger Prof. 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2008,120(23):4504-4507

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H. James Harwood  Kristin McNamara  James J. Johnson  Faith J. Wyzgoski 《Journal of polymer science. Part A, Polymer chemistry》2008,46(7):2347-2356

Nuclear magnetic resonance (NMR) analysis of the ¹³C‐labeled chain ends of polystyrene, polyMMA, and styrene‐MMA copolymers prepared by polymerizations initiated using ¹³C‐labeled‐phenacyl radicals were investigated. The phenacyl radicals were generated by anaerobic oxidation of acetophenone‐methyl‐¹³C using a Cu(II) octanoate‐pyridine complex in the presence of triethylamine and triphenylphosphine. NMR analysis of the ¹³C‐labeled chain ends of these polymers afforded insight into the initiation mechanism. In copolymerization experiments using ¹³C‐labeled acetophenone initiator, the NMR spectra provided evidence that the phenacyl radical reacts 2.7 times faster with styrene than with MMA. The resonances of the labeled phenacyl carbons also showed that the sequence and stereosequence distributions of monomer units at the chain ends are nearly the same as those that prevail along the polymer chains. Styrene–styrene, styrene–MMA, and MMA–styrene enchainments at the chain ends are equally likely to have meso (erythro) or racemic(threo) configurations but the ratio of meso to racemic MMA‐MMA enchainments is ～ 3/7. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2347–2356, 2008  相似文献   

    

John D. Andersen  Kristin L. M. Boylan  Feifei S. Xue  Lorraine B. Anderson  Bruce A. Witthuhn  Todd W. Markowski  LeeAnn Higgins  Amy P. N. Skubitz 《Electrophoresis》2010,31(4):599-610

Ovarian cancer is the fifth leading cause of cancer death for women in the US, yet survival rates are over 90% when it is diagnosed at an early stage, highlighting the need for biomarkers for early detection. To enhance the discovery of tumor‐specific proteins that could represent novel serum biomarkers for ovarian cancer, we depleted serum of highly abundant proteins which can mask the detection of proteins present in serum at low concentrations. Three commercial immunoaffinity columns were used in parallel to deplete the highly abundant proteins in serum from 60 patients with serous ovarian carcinoma and 60 non‐cancer controls. Medium and low abundance serum proteins from each serum pool were then evaluated by the quantitative proteomic technique of differential in‐gel electrophoresis. The number of protein spots that were elevated in ovarian cancer sera by at least twofold ranged from 36 to 248, depending upon the depletion and separation methods. From the 33 spots picked for MS analysis, nine different proteins were identified, including the novel candidate ovarian cancer biomarkers leucine‐rich α2 glycoprotein‐1 and ficolin 3. Western blotting validated the relative increases in serum protein levels for three of the proteins identified, demonstrating the utility of this approach for the identification of novel serum biomarkers for ovarian cancer.  相似文献   

    

Heiko Schirmer  Michael Duetsch  Frank Stein  Thomas Labahn  Burkhard Knieriem  Armin de Meijere 《Angewandte Chemie (International ed. in English)》1999,38(9):1285-1287

A novel mode of reaction towards arylethynes is shown by the β-trimethylsilyl-substituted α,β-unsaturated Fischer carbene complexes 1 . A mixture of the isomeric, highly substituted spiro[4.4]nonatrienes 2 and 3 is formed by the formal insertion of three alkyne molecules and subsequent cyclization (see scheme). Such selective triple insertions of alkynes into ethenylcarbene complexes have not been previously observed.  相似文献