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11.
The one-pot, three-step, four-component Ugi-IMDAF reaction with 5-hydroxymethylfurfural provides simple access to hydroxymethyl-substituted epoxyisoindolones in a diastereoselective and stereospecific manner. The protocol avoids the transfer or isolation of isocyanides, and the broad scope was illustrated by the synthesis of 22 different compounds bearing various substituents on the heterocyclic core. 相似文献
12.
Obydennov Dmitrii L. Simbirtseva Alena E. Sosnovskikh Vyacheslav Y. 《Research on Chemical Intermediates》2022,48(5):2155-2179
Research on Chemical Intermediates - Synthesis of 2-cyano-6-styryl-4-pyrones has been developed on the basis of 6-metylcomanic acid via modifications of the methyl and carboxyl groups. Reactions of... 相似文献
13.
Peter Schwendt Alena Oravcová Jarmila Tyršelová František Pavel?ík Jaromír Marek 《Polyhedron》1996,15(24):4507-4511
The vanadium(V) peroxo phosphato complex K7[V4O4(O2)8(PO4)]·9H2O has been obtained from the KVO3---KH2PO4---KOH---H2O2---H2O---C2H5OH system. The X-ray structural analysis revealed a tetranuclear anionic structure in which two dinuclear [V2O2(O)2)2(μ-η1 : η2-O2)2] units are connected by the μ4-PO4 group. 相似文献
14.
Spanová A Rittich B Styriak I Styriaková I Horák D 《Journal of chromatography. A》2006,1130(1):115-121
Carboxyl group-containing magnetic nonporous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) (P(HEMA-co-EDMA)) microspheres were used for the isolation of polymerase chain reaction (PCR)-ready DNA from samples of Baikal sediments. DNA was isolated using the phenol extraction method or the Soil DNA Isolation Kit. The occurrence of false-negative results in PCR caused by the presence of extracellular inhibitors in DNA samples was solved using solid phase reversible DNA immobilisation. PCR-ready DNA was reversibly adsorbed to the microspheres in the presence of 8.0% (w/v) poly(ethylene glycol) (PEG 6000) and 2.0M sodium chloride concentrations. The adsorbed DNA was released from the microspheres in a low ionic strength TE buffer. The quality of isolated DNA was checked by PCR amplification. 相似文献
15.
M Pérez M Fañanás-Mastral V Hornillos A Rudolph PH Bos SR Harutyunyan BL Feringa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(38):11880-11883
A highly efficient, regio- and enantioselective Cu(I) /phosphoramidite-catalyzed asymmetric allylic alkylation of allyl ethers with organolithium reagents is reported. The use of organolithium reagents is essential for this catalytic C?C bond formation due to their compatibility with different Lewis acids. The versatility of allylic ethers under the copper-catalyzed reaction conditions with organolithium reagents is demonstrated in the shortest synthesis of (S)-Arundic acid. 相似文献
16.
The method employing molecularly imprinted polymers for the extraction and clean up of endocrine‐disrupting compounds (estrogens, bisphenol A, and alkylphenols) from water and sediment is described. The identical extraction/clean‐up and LC‐MS/MS condition were used for the analysis of both types of samples. The method showed high recoveries ranging from 90 to 99% with excellent precision (intrabatch: 3.6–9.3%; interbatch: 5.6–11.4% for water; intrabatch: 4.3–8.5%; interbatch: 6.1–9.6% for sediment). The LOD was in the range of 0.7–1.9 ng/L and 0.3–0.6 ng/g for water and sediment, respectively. Overall extraction on molecularly imprinted polymers substantially enhanced sample clean‐up. The difference in efficiency of clean‐up was particularly pronounced when a large sample volume/weight was extracted and analyzed. Finally, the method was successfully applied for the analysis of 20 water and sediment samples. 相似文献
17.
High‐Pressure Synthesis of a Nitrogen‐Rich Inclusion Compound ReN8⋅x N2 with Conjugated Polymeric Nitrogen Chains 下载免费PDF全文
Dr. Maxim Bykov Dr. Elena Bykova Egor Koemets Timofey Fedotenko Georgios Aprilis Dr. Konstantin Glazyrin Dr. Hanns‐Peter Liermann Dr. Alena V. Ponomareva Johan Tidholm Dr. Ferenc Tasnádi Prof. Dr. Igor A. Abrikosov Prof. Dr. Natalia Dubrovinskaia Prof. Dr. Leonid Dubrovinsky 《Angewandte Chemie (International ed. in English)》2018,57(29):9048-9053
A nitrogen‐rich compound, ReN8?x N2, was synthesized by a direct reaction between rhenium and nitrogen at high pressure and high temperature in a laser‐heated diamond anvil cell. Single‐crystal X‐ray diffraction revealed that the crystal structure, which is based on the ReN8 framework, has rectangular‐shaped channels that accommodate nitrogen molecules. Thus, despite a very high synthesis pressure, exceeding 100 GPa, ReN8?x N2 is an inclusion compound. The amount of trapped nitrogen (x) depends on the synthesis conditions. The polydiazenediyl chains [?N=N?]∞ that constitute the framework have not been previously observed in any compound. Ab initio calculations on ReN8?x N2 provide strong support for the experimental results and conclusions. 相似文献
18.
Alena Pavelkova Pavel Kucharczyk Petr Stloukal Marek Koutny Vladimir Sedlarik 《先进技术聚合物》2014,25(6):595-604
The work presented here investigates the synthesis of poly(lactic acid)–poly(ethylene oxide) diisocyanate chain‐linked copolymer, and its application in the nano‐encapsulation of bioactive compounds. Study was conducted on the effect of the type of chain‐linking agent, along with molecular weight, thermal properties and hydrophilic/hydrophobic behavior, through the methods of gel permeation chromatography, Fourier transform infrared spectroscopy–attenuated total reflectance, differential scanning calorimetry, light scattering, water uptake experimentation, and water contact angle measurements. Nanoparticle formation was performed via a single solvent evaporation process, and the particles obtained were characterized by dynamic light scattering and scanning electron microscopy. Results show the significantly enhanced molecular weight of the final product after the chain‐linking reaction (up to 300,000 g/mol), as well as the non‐linear nature of the sample due to broad polydispersity, ranging from 4–13. The final products exhibited glass transition temperatures of between 30 and 44 °C, while their crystalline quality was either significantly suppressed or a completely amorphous attribute was observed. Nanoparticles in the range of 300 nm that contained metazachlor were successfully prepared, and their releasing behavior exhibited first order release kinetics. A slower rate of release was observed in samples containing 4,4′‐methylenebis(phenyl isocyanate) as a chain‐linker. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
19.
Immunomagnetic separation and detection of Salmonella cells using newly designed carriers 总被引:1,自引:0,他引:1
Spanová A Rittich B Horák D Lenfeld J Prodelalová J Suciková J Strumcová S 《Journal of chromatography. A》2003,1005(1-2):215-221
A new method for simultaneous determination of alkoxyethanols (2-methoxyethanol, 2-ethoxyethanol, 2-isopropoxyethanol, and 2-butoxyethanol) by high-performance liquid chromatography (HPLC) with fluorescence detection has been developed. The alkoxyethanols and an internal standard (2-phenoxyethanol) were derivatized by treatment with 1-anthroylnitrile to give the anthroyl esters. The esterification was completed in 30 min in the presence of quinuclidine as base catalyst at room temperature. After stopping the reaction, an aliquot of the final solution was injected into the HPLC. The resulting anthroyl esters of the alkoxyethanols and the internal standard were separated on a C18 reversed-phase column with acetonitrile-water-acetic acid (65:35:0.1, v/v) as the mobile phase and detected fluorimetrically at excitation and emission wavelengths of 360 nm and 460 nm, respectively. The detection limits of the derivatives as alkoxyethanols at a signal-to-noise ratio of 3 were in the range of 1-3 pg per injection. The minimal amounts of alkoxyethanols derivatized in the reaction mixture for derivatization to determine the limits of detection were approximately 0.5 ng. This HPLC method was applied to the determination of some of alkoxyethanols in the air of the workplace where the thinner containing alkoxyethanols was used for painting. 相似文献