共查询到20条相似文献,搜索用时 78 毫秒
1.
Kevin Blades Julie DemerittShaun Fillery Kevin M. FooteRyan Greenwood Clare GregsonLorraine A. Hassall Thomas M. McGuireKurt G. Pike Emma Williams 《Tetrahedron letters》2014
Two novel synthetic strategies that allow rapid diversification of the sulfone moiety in sulfonylmethyl pyrimidines, a class of compounds with a wide range of biological activity, which are of interest in a wide variety of drug discovery programmes, are described. 相似文献
2.
In x-ray fluorescence spectrometry, matrix effects have to be corrected. The empiric equations, the theoretical coefficients and the fundamental parameters can be applied in the purpose. The classical matrix correction models include mainly Lachance-Trail,Rousseau, De Jongh, Claisse-Quentin, COLA algorithms,etc. The good results can be obtained by using a number of standards or the theoretical Alpha coefficients if the range of component concentrations in samples is not very wide. When unknown samples with a wide range of concentrations are predicted, a recalculation process of the theoretical Alpha coefficients has to be made. In addition, a spline function may be chosen to split wide range in several segments. 相似文献
3.
Xiao‐Bo Ding Daniel P. Furkert Margaret A. Brimble 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(34):11956-11961
Syn dihydroxyketone motifs are embedded in a wide range of biologically active natural products, however the development of stereoselective synthetic methods to assemble these structures has proven a challenging task. We report a highly diastereoselective method for the synthesis of syn dihydroxyketones from propargylic alcohols, with wide scope for application in natural product synthesis. The reaction sequence involves regioselective cyclisation of propargylic alcohols with incorporation of a triketone to give enol dioxolanes that are then diastereoselectively epoxidised to form unusual spiroepoxide intermediates. Hydrolysis affords syn dihydroxyketones as essentially single diastereisomers. The reaction sequence is operationally simple, of wide substrate scope, and remarkably can be efficiently carried out as a one‐pot process with no loss of overall yield or diastereoselectivity. 相似文献
4.
Summary A simple procedure was developed for preparing wide pore (≦ 40nm) silicas from a common chromatographic silica gel. The effects
of various experimental conditions on pore size, pore volume, and surface area are discussed. The results show that under
controlled conditions a wide variety of wide pore silica packing materials can be prepared.
Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984 相似文献
5.
A wide range of mesophases are induced on treating polycatenar complexes of silver(I) with a wide range of organic solvents. 相似文献
6.
Francis M. Mirabella 《Journal of Polymer Science.Polymer Physics》1985,23(5):861-871
The use of band-ratioing techniques in internal reflection spectroscopy (IRS) for a wide variety of polymer surface composition and orientation measurements is discussed. It is shown that quantitative data can be obtained under a wide range of experimental conditions. The effects of variations in sample contact, internal reflection element, and angle of incidence are considered in detail. The applicability and limitations of calibration procedures for the determination of surface composition under various experimental conditions are considered. The requirements for obtaining quantitative results by IRS are shown to be far more lenient than is typically assumed. 相似文献
7.
Summary A method for optimization of the mobile phase composition in ion exchange chromatography with a wide range external pH gradient (approx. over 5 pH units) has been formulated. It is shown that programming of various wide range pH profiles which are not impaired by buffer interactions of the mobile phase with sorbent is possible. Utilization of the wide range external pH gradient in cation-exchange chromatography of bovine haemoglobin is also demonstrated. 相似文献
8.
I. K. Khairullin A. G. Sinaiskii I. V. Dal’gren M. P. Pomanskaya I. I. Khairullin M. A. Chebotarev 《Polymer Science Series D》2013,6(1):72-76
Results are presented of investigations devoted to the creation of polymer compositions using oligomeric urethane-siloxane rubbers as basic polymers (foreign analogs are STO, SPUR or STP polymers). The sealants developed based on these binding materials exhibit a wide range of rates of curing, good physicomechanical characteristics, and high adhesion to various substrates. The corresponding low-, medium-, and high-modulus polymer compositions may find wide application in automobile and transport engineering, shipbuilding, the construction industry, and other fields. 相似文献
9.
E. Paillard F. Toulgoat R. Arvai C. Iojoiu L. Cointeaux M. Medebielle F. Alloin B. Langlois J.-Y. Sanchez 《Journal of fluorine chemistry》2011,132(12):1213-1218
This paper reports both on a general multistep synthesis of a wide family of aryl substituted perfluorosulfonimides and on a preliminary electrochemical investigation of two lithium salts hosted by a poly(oxyethylene) homopolymer. Both salts have a cationic transference number more than twice that of LiTFSI. Additionally, one of these salts exhibits markedly higher cationic conductivities than POE/LiTFSI electrolytes. These preliminary data are very encouraging as, thanks to the aryl moiety, a wide variety of salts can be considered in order to still improve the performances of polymer electrolytes. 相似文献
10.
《Journal of membrane science》1988,39(2):125-141
The role of dilute suspensions in fouling a ultrafilter tubular membrane module is studied in detail for a wide range of wall permeation flux conditions. The inlet flow profiles are assumed to be either uniform (plug flow) or parabolic (fully developed) shape. It is assumed that the particles are neutrally buoyant and the concentrations are so low that it does not influence the fluid flow. Furthermore, the particle-particle interactions and the forces of interaction between the particle and the membrane wall are assumed to be unimportant. The governing equations of motion for the fluid are solved by a finite difference scheme. To compute the particulate fouling, the equations of motion for the particles are solved by the fourth-order Runge-Kutta-Gill method. Results are presented for both hydrodynamics and membrane fouling by dilute suspensions for conditions such as the effect of assumed inlet velocity profiles, and a wide range of wall permeation flux conditions. 相似文献
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12.
D. R. Williams J. S. Hislop A. P. Mead T. W. Sanders D. A. Wood 《Journal of Radioanalytical and Nuclear Chemistry》1979,48(1-2):213-228
A sensitive activation technique for the determination of trace levels of oxygen in a wide range of materials is described
with particular emphasis on the γ-irradiation facilities at AERE Harwell and experience of the use of the technique over a
number of years. Procedures for removing surface oxygen contamination prior to determination of bulk oxygen concentrations
are given, together with details of the radiochemical separation procedures used for a wide range of materials, and examples
of the results obtained. 相似文献
13.
G B Lockwood 《Journal of chromatography. A》2001,936(1-2):23-31
The commercial importance of the volatile mono- and sesqui-terpenoids has resulted in a wide range of techiques being used for extraction, concentration, chromatography, and characterisation of constituents. The major chromatographic technique is gas chromatography, and tandem techniques of chromatography linked to further chromatography and spectroscopy, allow much increased resolution, and greater ease of characterisation of terpenes. A wide range of extraction techniques are discussed, and suitability for particular matrices and sample sizes outlined. Chromatography operating conditions and stationary phases, and techniques for solute identification are laid out. A number of applications of terpene analysis in many different matrices are discussed. 相似文献
14.
Stable single fingers evolving in a thin layer of hydrodynamically unstable reactive solution are investigated in moderately wide Hele-Shaw cells. The mixing length associated with the final pattern is shown to be proportional to the width of the container. The scaling law, which is best illustrated by the overlay of temporal average front profiles, is demonstrated for two chemical compositions and boundaries of different thermal conductances. The observed single finger is found to be independent of the orientation of the reaction vessel for a wide range of tilt angles. 相似文献
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16.
The paper is dedicated to determining the partial and apparent molar volumes of aqueous electrolytes in a wide concentration range where formulas are commonly employed that are applicable only for very low concentrations. 相似文献
17.
Aditya Kumar Yuan Gao Philippe H. Geubelle 《Journal of polymer science. Part A, Polymer chemistry》2021,59(11):1109-1118
This note presents approximate analytical expressions for the velocity of the self-propagating reaction front in the frontal polymerization of thermoset polymers and composites. Prior estimates available in the literature for the front velocity have been limited by their applicability to simple reaction kinetics. The improved estimates provided in this work are shown to be applicable to complex reaction kinetics encountered in the frontal polymerization of neat thermoset polymers or fiber-reinforced polymer-matrix composites with a wide range of polymer chemistries, including dicyclopentadiene, cyclooctadiene, acrylates, and epoxies. They are also shown to be applicable to wide range of values of the initial temperature and initial degree of cure of the resin, and of the volume fraction of the reinforcing phase. 相似文献
18.
《The Chemical Engineering Journal》1993,51(1):45-52
The expansion of conical spouted beds has been studied on a wide experimental base (using contactors of different geometries and solids of different diameters and sphericities). The correlation obtained for calculating the global voidage from the operation conditions is of a more general application than those previously proposed in the literature, which are generally centred on the study of voidage in the spout. The global incipient voidages are delimited for both stable regimes corresponding to two voidage ranges: spouting and jet spouting. While the correlation for calculation of expansion can be applied for the calculation of global minimum jet spouting voidage, a correlation is proposed for the calculation of the global minimum spouting voidage. This equation is applicable in a wide range of operation conditions. 相似文献
19.
Electron-deficient 1- and 2-azabuta-1,3-dienes are reagents intrinsically able to provide a wide range of cyclic and acyclic N-containing building blocks. Depending on their substitution, they behave as dienes for Diels-Alder reactions, as partners for [4+1], [3+2], [2+2]-cycloadditions, for aziridinations and as electrophiles for 1,2 and 1,4-additions. Nowadays, they are a very versatile family of compounds, despite their usual instability and complex reactivity. Four decades of research in this challenging area are reviewed in this critical review: their synthetic aspects and their reactivity towards a wide range of dienophiles, dipoles and nucleophiles are described as well. The introduction focuses on their electronic properties in order to get a clear picture of their reactivity (190 references). 相似文献
20.
An efficient one-pot synthetic approach to access a variety of 3-(indol-3-yl)quinoxalin-2-ones from various quinoxalin-2-ones and very wide scope of indoles through TfOH-catalyzed Friedel-Crafts type coupling reaction in DMF has been developed. Only 10 mol % Brønsted acid as a catalyst, air as an oxidizer, and very wide range of substrates are the prominent advantages of this method. 相似文献