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891.
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894.
Stephen G. Davies Ai M. Fletcher Linlu Lv Paul M. Roberts James E. Thomson 《Tetrahedron: Asymmetry》2012,23(11-12):910-925
The conjugate addition of lithium (R)-N-benzyl-N-(α-methylbenzyl)amide to a range of β-fluoroaryl-α,β-unsaturated esters gave the corresponding β-amino esters with high diastereoselectivity and in good isolated yields. Sequential treatment of the resultant β-fluoroaryl-β-amino esters under optimised hydrogenolysis conditions, followed by ester hydrolysis with 2.0 M aq HCl, provided access to a range of β-fluoroaryl-β-amino acids in good yield. 相似文献
895.
Paul P. Dillon Stephen J. Daly Anthony J. Killard Richard O'kennedy 《International journal of environmental analytical chemistry》2013,93(7-8):525-543
The interaction between antibody and antigen is characterised by relatively high affinity and specificity, making this type of reaction a prime candidate for use as an analytical tool. The interaction may be combined with biosensors in the production of immunosensors for environmental monitoring. Polyclonal and monoclonal antibodies have had a significant impact in analytical detection systems over the past few decades with antibody fragments becoming important in recent years. Production of antibodies to small haptens requires the initial conjugation of hapten to a larger carrier molecule. Once hapten-carrier conjugates have been produced, polyclonal, monoclonal and various antibody fragments may be produced by differing protocols. A critical step in the production of antibody fragments is the development of efficient screening procedures to identify suitable antibody-producing clones and this has been reviewed in this article. Various antibody types may then be used in the generation of immunosensors for the monitoring of environmental pollutants. The selection of the appropriate sensor technology applicable for the determination of an antibody-antigen interaction is of prime importance for immunosensor development. One example of such an application is surface plasmon resonance-based biosensors, as they provide real-time analysis of interactions between the antibody and antigen of interest. 相似文献
896.
Ioan Paraschiv Paul Delforterie Marcel Giesbers Maarten A. Posthumus 《Liquid crystals》2013,40(8):977-983
The synthesis and phase behaviour of a new series of unsymmetrically substituted hexaalkoxytriphenylene‐based liquid crystals are reported. One of the hexyloxy chains in hexahexyloxytriphenylene (HAT6) is replaced by either a shorter or a longer chain, HAT‐(OC6H13)5(OC n H2n+1). Compounds with chain lengths n of 2–14, 16 and 18 were prepared and investigated. Compounds with n?13 were not liquid crystalline. For all compounds with n?12 Colh textures were observed by polarizing microscopy. X‐ray investigations showed that the intercolumnar distance gradually increased with n from n = 2 to n = 12, while the interdisk distance (3.6 Å) remained constant. A small odd–even effect on the increase of the intercolumn distance with n was observed. This effect was also found in the change of ΔH of isotropization with n. 相似文献
897.
An improved and eco‐friendly procedure has been developed to generate mesoporous silica‐supported palladium nanoparticles (SiO2@PdNP) that could be used as a sustainable heterogeneous Pd catalyst for phosphine‐free Suzuki–Miyaura and Heck coupling reactions with excellent turnover number and turnover frequency. The presence of Pd on the silica surface was detected by X‐ray diffraction and the structural morphology of SiO2@PdNP was obtained by transmission electron microscopy. The heterogeneous catalytic system is recyclable and leaching of the metal after the reaction is not apparently observed. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
898.
Keng Lung Lee Joey Feld Dr. Paul Hume Prof. Tilo Söhnel Dr. Erin Leitao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(2):815-824
A series of ammonium monosubstituted H-phosphonate salts were synthesized by combining H-phosphonate diesters with amines in the absence of solvent at 80 °C. Variation of the ester substituent and amine produced a range of ionic liquids with low melting points. The products and by-products were analyzed by spectroscopic and spectrometric techniques in order to get a better mechanistic picture of the dealkylation and formal dearylation observed. For dialkyl H-phosphonate diesters, (RO)2P(O)H (R=alkyl), the reaction proceeds via direct dealkylation with the reactivity increasing in the order R=iPr<Et<Me corresponding to DFT calculated activation enthalpies of 22.6, 20.8, and 17.9 kcal mol−1. For the diphenyl H-phosphonate diesters, (PhO)2P(O)H, the dearylation was found to proceed via phenol-assisted formation of a 5-coordinate intermediate, (PhO)3PH(OH), from which P(OPh)3 and water were eliminated. The presence of an equivalent of water then facilitated the formation of P(OH)2OPh and the amine, R'NH2, subsequently abstracted a proton from it to yield [(PhO)PH(O)O]-[R'NH3]+. 相似文献
899.
Serge Raynal Gilberte Ndebeka Paul Caubere Satira Suparno Joseph Sledz Francois Schue 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):667-674
The stereoregularity of polystyrenes obtained with complex bases and salt complex bases in various solvents was determined by 13C-NMR spectroscopy. Polystyrenes produced by complex bases are mostly syndiotactic and obey Bernoullian statistics. 相似文献
900.
Didier Lesesvre Paul Pegon Filippo Santambrogio 《Set-Valued and Variational Analysis》2013,21(3):541-556
The main result of this paper is the existence of an optimal transport map T between two given measures μ and ν, for a cost which considers the maximal oscillation of T at scale δ, given by ω δ (T) :?=??sup|x???y|?<?δ |T(x)???T(y)|. The minimization of this criterion finds applications in the field of privacy-respectful data transmission. The existence proof unfortunately only works in dimension one and is based on some monotonicity considerations. 相似文献