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161.
Ivan I. Stoikov Dina S. Ibragimova Nadezhda V. Shestakova Dmitry B. Krivolapov Igor A. Litvinov Igor S. Antipin 《Supramolecular chemistry》2013,25(7):564-571
The preparation of partially substituted thiacalix[4]arenes 2–6 has been accomplished by conducting the reaction of the thiacalixarene 1 with N-(p-nitrophenyl)-α-bromoacetamide in acetone or acetonitrile in the presence of M2CO3 (M = Na, K and Cs). The influence of the reaction conditions (temperature, time, solvent, ratio of the reagents and the nature of the alkali metal carbonate) on regio- and stereoselectivity of this reaction is described. 相似文献
162.
Igor S. Antipin Ivan I. Stoikov Grigory N. Nikonov Alexander I. Konovalov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract A new series of calixcrown compounds (11) containing some VA group elements (N, P) was synthesized. 1.3-bis-(aminoethoxy) calix[4]arene (I) was used as starting platform for the preparation of calixcrown compounds. Reaction of (I) with bis(a-hydroxyalky1)phenylphosphines in toluene lead to phosphadiazacalixcrown compounds (11). All obtained receptors are hydrolytic stable and are not oxidized by air. A more convenient synthesis of (II) involves treatment of (I) with 2.5-diphenyl-1.3.2.5-dioxaboraphosphorinanes (III) which are stable on air unlike bis-(a-hydroxyalkyl) phenylphosphines. Structure of obtained macrocycles was established by 1H and 31P NMR spectroscopy. 相似文献
163.
Anastasiia M. Mishura Anna S. Sklyarova Dmitriy I. Sharapa Igor’ A. Levandovsky Michael Serafin Andrey A. Fokin Vladimir N. Rodionov 《Central European Journal of Chemistry》2013,11(12):2144-2150
The rearrangement of easily accessible Cookson’s diketone with chlorosulfonic acid in chloroform followed by the acidic hydrolysis gave 6-chloro-7-hydroxy-dichloropentacyclo[6.3.0.02,6.03,10.05,9]undecane-4-one, whose syn-stereochemistry was assigned through the X-ray crystal structure analysis. This key structure was used for the stereoselective synthesis of the D 3-trishomocubane derivatives as well as for the preparation of potential drugs bearing hydroxy- and amino-functional groups. A new multigram preparative synthesis of D 3-trishomocubane was developed. 相似文献
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Tyler T. Clikeman Dr. Igor V. Kuvychko Dr. Natalia B. Shustova Dr. Yu‐Sheng Chen Dr. Alexey A. Popov Dr. Olga V. Boltalina Prof. Steven H. Strauss 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(16):5070-5080
The sequential addition of CN? or CH3? and electrophiles to three perfluoroalkylfullerenes (PFAFs), Cs‐C70(CF3)8, C1‐C70(CF3)10, and Cs‐p‐C60(CF3)2, was carried out to determine the most reactive individual fullerene C atoms (as opposed to the most reactive C?C bonds, which has previously been studied). Each PFAF reacted with CH3? or CN? to generate metastable PFAF(CN)? or PFAF(CH3)22? species with high regioselectivity (i.e., one or two predominant isomers). They were treated with electrophiles E+ to generate PFAF(CN)(E) or PFAF(CH3)2(E)2 derivatives, also with high regioselectivity (E+=CN+, CH3+, or H+). All of the predominant products, characterized by mass spectrometry and 19F NMR spectroscopy, are new compounds. Some could be purified by HPLC to give single isomers. Two of them, C70(CF3)8(CN)2 and C70(CF3)10(CH3)2(CN)2, were characterized by single‐crystal X‐ray diffraction. DFT calculations were used to propose whether a particular reaction is under kinetic or thermodynamic control. 相似文献
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A novel approach utilizing automated Raman microspectroscopic mapping for gunshot residue (GSR) detection was investigated. A well-established technique for GSR recovery (tape lifting) was utilized for GSR particle collection. Uncontaminated samples of the substrate (tape), organic GSR (OGSR), and inorganic GSR (IGSR) particles were characterized to generate three respective Raman spectroscopic training sets. Automated Raman mapping was used to rapidly collect spectra over areas of the tape substrate populated with GSR particles. Raman spectra collected from the maps were classified against the training sets via partial least squares discriminant analysis (PLS-DA) to determine if GSR was present. We report the application of Raman chemical mapping as a proof of concept for the positive detection of GSR particles of varying morphologies. The estimated size of GSR particles, which could be readily detected by this method, is about 3.4 μm. The efficiency of the classification was quantitated with rates of true positives and negatives. Validation studies scrutinizing the practicality of this approach as a viable tool for potential forensics investigations are currently in progress. Figure
The figure illustrates a novel approach for the recovery and identification of gunshot residue on adhesive tape. The emerging approach combines tape lifting and a rapid, non-destructive Raman spectroscopic scanning over the tape, which was used for collecting GSR from a surface of interest. Detection of GSR is achieved through multivariate classification of mapping spectra against a known training set. 相似文献
170.
Yury Kostyukevich Alexey Kononikhin Alexander Zherebker Igor Popov Irina Perminova Eugene Nikolaev 《Analytical and bioanalytical chemistry》2014,406(26):6655-6664
We report a simple approach for enumeration of non-labile oxygen atoms in individual molecules of dissolved organic matter (DOM), using acid-catalyzed 16O/18O exchange and ultrahigh-resolution Fourier-transform ion-cyclotron-resonance mass spectrometry (FTICR-MS). We found that by dissolving DOM in H2 18O at 95 °C for 20 days it is possible to replace all oxygen atoms of DOM molecules (excluding oxygen from ether groups) with 18O. The number of exchanges in each molecule can be determined using high-resolution FTICR. Using the proposed method we identified the number of non-labile oxygen atoms in 231 molecules composing DOM. Also, using a previously developed hydrogen–deuterium (H/D)-exchange approach we identified the number of labile hydrogen atoms in 450 individual molecular formulas. In addition, we observed that several backbone hydrogen atoms can be exchanged for deuterium under acidic conditions. The method can be used for structural and chemical characterization of individual DOM molecules, comparing different DOM samples, and investigation of biological pathways of DOM in the environment. 相似文献