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Dr. Konstantin I. Galkin Bogdan Ya. Karlinskii Dr. Alexander Yu. Kostyukovich Dr. Evgeniy G. Gordeev Prof. Dr. Valentine P. Ananikov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(39):8567-8571
This work reveals ambident nucleophilic reactivity of imidazolium cations towards carbonyl compounds at the C2 or C4 carbene centers depending on the steric properties of the substrates and reaction conditions. Such an adaptive behavior indicates the dynamic nature of organocatalysis proceeding via a covalent interaction of imidazolium carbenes with carbonyl substrates and can be explained by generation of the H-bonded ditopic carbanionic carbenes. 相似文献
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Baíllo Amparo Cárcamo Javier Getman Konstantin 《Advances in Data Analysis and Classification》2019,13(2):531-557
Advances in Data Analysis and Classification - The classification of the X-ray sources into classes (such as extragalactic sources, background stars,...) is an essential task in astronomy.... 相似文献
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Dr. Alexey S. Kiryutin Dr. Grit Sauer Dr. Daniel Tietze Martin Brodrecht Stephan Knecht Prof. Dr. Alexandra V. Yurkovskaya Prof. Dr. Konstantin L. Ivanov Dr. Olga Avrutina Prof. Dr. Harald Kolmar Prof. Dr. Gerd Buntkowsky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4025-4030
Two-dimensional NMR spectroscopy is one of the most important spectroscopic tools for the investigation of biological macromolecules. However, due to the low sensitivity of NMR spectroscopy, it takes usually from several minutes to many hours to record such spectra. Here, the possibility of detecting a bioactive derivative of the sunflower trypsin inhibitor-1 (SFTI-1), a tetradecapeptide, by combining parahydrogen-induced polarization (PHIP) and ultrafast 2D NMR spectroscopy is shown. The PHIP activity of the inhibitor was achieved by labeling with O-propargyl-l -tyrosine. In 1D PHIP experiments a signal enhancement of a factor of approximately 1200 compared to standard NMR was found. This enhancement permits measurement of 2D NMR correlation spectra of low-concentrated SFTI-1 in less than 10 seconds, employing ultrafast single-scan 2D NMR detection. As experimental examples PHIP-assisted ultrafast single-scan TOCSY spectra of SFTI-1 are shown. 相似文献
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Marco Reichel Mara Egenhöfer Burkhard Krumm Konstantin Karaghiosoff 《无机化学与普通化学杂志》2020,646(6):328-331
Fluoromethylating agents are a highly studied and controversely discussed class of compounds. New fluoromethyl pseudohalides FCH2N3, FCH2SCN, and FCH2SeCN were prepared for the first time and their physical and spectroscopic properties investigated. Their synthesis is performed conveniently by fluoromethylation of the respective silver or potassium pseudohalogenides with fluoroiodomethane. 相似文献
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Treatment of glycosyl halides with NaN3 in aqueous acetone or acetonitrile is a convenient method for the stereoselective synthesis of 1,2-trans-per-O-acetyl-glycosyl azides. 相似文献