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51.
Yulia B. Monakhova Svetlana P. Mushtakova Thomas Kuballa Dirk W. Lachenmeier 《Magnetic resonance in chemistry : MRC》2014,52(12):755-759
An eight‐fold suppression pulse sequence was recently developed to improve sensitivity in 1H NMR measurements of alcoholic beverages [Magn. Res. Chem. 2011 (49): 734–739]. To ensure that only one combined hydroxyl peak from water and ethanol appears in the spectrum, adjustment to a certain range of ethanol concentrations was required. To explain this observation, the structure of water–ethanol solutions was studied. Hydroalcoholic solutions showed extreme behavior at 25% vol, 46% vol, and 83% vol ethanol according to 1H NMR experiments. Near‐infrared spectroscopy confirmed the occurrence of four significant compounds (‘individual’ ethanol and water structures as well as two water–ethanol complexes of defined composition – 1 : 1 and 1 : 3). The successful multiple suppression can be achieved for every kind of alcoholic beverage with different alcoholic strengths, when the final ethanol concentration is adjusted to a range between 25% vol and 46% vol (e.g. using dilution or pure ethanol addition). In this optimum region, an individual ethanol peak was not detected, because the ‘individual’ water structure and the 1 : 1 ethanol–water complex predominate. The nature of molecular association in ethanol–water solutions is essential to elucidate NMR method development for measurement of alcoholic beverages. The presented approach can be used to optimize other NMR suppression protocols for binary water–organic solvent mixtures, where hydrogen bonding plays a dominant role. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
52.
Inside Cover: Lipid Nanotube Tailored Fabrication of Uniquely Shaped Polydopamine Nanofibers as Photothermal Converters (Chem. Eur. J. 13/2016) 下载免费PDF全文
53.
Natalia Monakhova Svetlana Ryabova Vadim Makarov 《Journal of heterocyclic chemistry》2016,53(3):685-709
The procedures for the synthesis of substituted pyrrolo[1,2‐a]indoles and some of their biological properties are reviewed. 相似文献
54.
Vladimir A. Potapov Svetlana V. Amosova Boris V. Petrov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):587-590
Reactions of dicyanodiselenide, selenenyl chlorides and bromides with acetylenes and some further transformations of obtained products have been studied. 相似文献
55.
Vera I. Maslennikova Elena V. Shkarina Svetlana E. Goriukhina Tatiana K Sinicina Roman V. Merkulov Edward E. Nifantyev 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract New types of phosphocavitandes differing in structure of phosphorus surroundings were synthesized and investigated. 相似文献
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Yana I. Sakhno Svetlana V. Shishkina Oleg V. Shishkin Vladimir I. Musatov Elena V. Vashchenko Sergey M. Desenko Valentin A. Chebanov 《Molecular diversity》2010,14(3):523-531
Heterocyclization reactions of pyruvic acids, aromatic aldehydes and 5-amino-N-aryl-1H-pyrazole-4-carboxamides yielding four different types of final compounds are described. The reactions involving arylidenpyruvic
acids lead with high degree of selectivity to either 4,7-dihydropyrazolo[1,5-a]pyrimidine-5-carboxylic acids or 5-[(2-oxo-2,5-dihydrofuran-3-yl)amino]-1H-pyrazoles, depending on the catalyst type or temperature regime. The interactions based on arylpyruvic acids can take place
under kinetic or thermodynamic control producing 7-hydroxy-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine-7-carboxylic acids or 3-hydroxy-1-(1H-pyrazol-5-yl)-1,5-dihydro-2H-pyrrol-2-ones, respectively. 相似文献
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Christian Renicke Daniel Schuster Svetlana Usherenko Lars-Oliver Essen Christof Taxis 《Chemistry & biology》2013,20(4):619-626
Highlights? Optogenetic tool to control the stability of soluble and membrane proteins ? Engineered using the LOV2 domain and a murine ornithine decarboxylase-like degron ? Creation of light-switchable, conditional mutants ? Graded response to very low blue light intensities allows yeast photography 相似文献