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261.
Tamara Kovcs Laura Sz. Fülp Zoltn Mucsi Konstantin Karaghiosoff Mtys Czugler Gyrgy Keglevich 《Heteroatom Chemistry》2015,26(5):335-347
A series of 1‐alkyl‐3‐methyl‐2,5‐dihydro‐1H‐phosphole oxides were converted to the corresponding phosphole oxides that, by the Diels–Alder reaction with N‐maleimide derivatives or with another unit of phosphole oxide, yielded trapped phosphole oxides or phosphole oxide dimers, respectively, as new 7‐phosphanorbornene 7‐oxides. The stereostructures of three derivatives were evaluated by single crystal X‐ray analysis. The regio‐ and stereospecific dimerization was studied by B3LYP/6‐31G(d,p) quantum chemical calculations, whose results were in accord with syntheses. Novel mechanistic features were explored. The geometrical data obtained by single crystal X‐ray analysis validated the results of quantum chemical calculations, as the deviation was less than 3%. 相似文献
262.
Pavel . Volkov Nina I. Ivanova Nina K. Gusarova Boris G. Sukhov Kseniya O. Khrapova Lev E. Zelenkov Vladimir I. Smirnov Tatyana N. Borodina Tamara I. Vakul'skaya Spartak S. Khutsishvili Boris A. Trofimov 《Heteroatom Chemistry》2015,26(5):329-334
Secondary phosphine chalcogenides react with diacetone‐d‐glucose (DAG) in the system CCl4/Et3N (70°C, 4–24 h) to afford DAG chalcogenophosphinates in up to 79% yield, thus paving a short way to optically active chalcogenophosphinates with glucose moieties. As an example, a mild regioselective hydrolysis (70°C, aqueous MeCOOH) of DAG bis(2‐phenylethyl)selenophosphinate) obtained leads to monoacetone‐d‐glucose bis(2‐phenylethyl)selenophosphinate. 相似文献
263.
The deoxygenation of a few diaryl‐phenylphosphine oxides, dimethyl‐phenylphosphine oxide, and 3‐methyl‐1‐phenyl‐3‐phospholene 1‐oxide was studied by phenylsilane, tetramethyldisiloxane (TMDS), and polymethylhydrosiloxane (PMHS) under conventional or microwave (MW) heating, in toluene or in the absence of any solvent at different temperatures. It was found that the deoxygenation with TMDS or PMHS under MW and solvent‐free conditions may be the method of choice and provides a green chemical approach. 相似文献
264.
Three efficient strategies for derivatization of the anticancer drug candidate amonafide (Quinamed, originally AS1413) are described. Unprecedented reductive amination of aryl aldehydes, SNAr, and addition–elimination reactions, while using readily available starting materials, give quick entry to potential libraries of novel 3-aryl, 3-benzyl N-derivatives of amonafide. The selective anticancer activity of this important DNA intercalation agent is expected to be enhanced by expanding the diversity of amonafide N-derivatives. The synthetic routes reported in this work are general and readily applicable. 相似文献
265.
Visual Displays that Directly Interface and Provide Read‐Outs of Molecular States via Molecular Graphics Processing Units
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Julia E. Poje Tamara Kastratovic Andrew R. Macdonald Ana C. Guillermo Steven E. Troetti Dr. Omar J. Jabado M. Leigh Fanning Prof. Darko Stefanovic Dr. Joanne Macdonald 《Angewandte Chemie (International ed. in English)》2014,53(35):9222-9225
The monitoring of molecular systems usually requires sophisticated technologies to interpret nanoscale events into electronic‐decipherable signals. We demonstrate a new method for obtaining read‐outs of molecular states that uses graphics processing units made from molecular circuits. Because they are made from molecules, the units are able to directly interact with molecular systems. We developed deoxyribozyme‐based graphics processing units able to monitor nucleic acids and output alphanumerical read‐outs via a fluorescent display. Using this design we created a molecular 7‐segment display, a molecular calculator able to add and multiply small numbers, and a molecular automaton able to diagnose Ebola and Marburg virus sequences. These molecular graphics processing units provide insight for the construction of autonomous biosensing devices, and are essential components for the development of molecular computing platforms devoid of electronics. 相似文献
266.
Milica Milošević Marija Radoičić Zoran Šaponjić Tim Nunney Christopher Deeks Vesna Lazić Miodrag Mitrić Tamara Radetić Maja Radetić 《Cellulose (London, England)》2014,21(5):3781-3795
The possibility of in situ photoreduction of Ag+-ions using TiO2 nanoparticles deposited on cotton and cotton/PET fabrics in the presence of amino acid alanine and methyl alcohol has been discussed. The possible interaction between TiO2, alanine and Ag+-ions was evaluated by FTIR analysis. The fabrication of TiO2/Ag nanoparticles on both fabrics was confirmed by SEM, EDX, XRD, XPS and AAS analyses. Cotton and cotton/PET fabrics impregnated with TiO2/Ag nanoparticles provided maximum reduction of Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus. Although excellent antibacterial activity was preserved after ten washing cycles, a significant amount of silver leached out from the fabrics into the washing bath. The perspiration fastness assessment revealed that smaller amounts of silver were also released from the fabrics into artificial sweat at pH 5.50 and 8.00. In addition, deposited TiO2/Ag nanoparticles imparted maximum UV protection to fabrics. 相似文献
267.
Tamara Besselink Albert van der Padt Anja E.M. Janssen Remko M. Boom 《Journal of chromatography. A》2013,1271(1):105-114
Radial flow chromatography can be a solution for scaling up a packed bed chromatographic process to larger processing volumes. In this study we compared axial and radial flow affinity chromatography both experimentally and theoretically. We used an axial flow column and a miniaturized radial flow column with a ratio of 1.8 between outer and inner surface area, both with a bed height of 5 cm. The columns were packed with affinity resin to adsorb BSA. The average velocity in the columns was set equal. No difference in performance between the two columns could be observed. To gain more insight into the design of a radial flow column, the velocity profile and resin distribution in the radial flow column were calculated. Using mathematical models we found that the breakthrough performance of radial flow chromatography is very similar to axial flow when the ratio between outer and inner radius of the radial flow column is around 2. When this ratio is increased, differences become more apparent, but remain small. However, the ratio does have a significant influence on the velocity profile inside the resin bed, which directly influences the pressure drop and potentially resin compression, especially at higher values for this ratio. The choice between axial and radial flow will be based on cost price, footprint and packing characteristics. For small-scale processes, axial flow chromatography is probably the best choice, for resin volumes of at least several tens of litres, radial flow chromatography may be preferable. 相似文献
268.
The basic concepts of optical parametric processes and recent results on broadly tunable high-repetition rate femtosecond Optical Parametric Oscillators (fs OPO) are reviewed. Ti:Sapphire-Laser pumped KTP, KTA, and CTA fs OPOs and intracavity-doubled fs KTP OPO in particular are discussed. 相似文献
269.
Robert C. Powers 《Order》1990,7(1):83-96
The purpose of this paper is to introduce a class of mappings from a lattice L, whose elements are residuated maps, into itself. The main results of this paper identify certain injective residuated mappings of L and order automorphisms of a sublattice of L with mappings from this class. 相似文献
270.