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41.
Abdellatif Moudafi 《Numerical Functional Analysis & Optimization》2013,34(9-10):1013-1021
Recently Auslender & Crouzeix introduced a well-behaved asymptotical notion for convex functions. The aim of this work is to extend this notion to the saddle case 相似文献
42.
Abdellatif Moudafi 《Optimization Letters》2010,4(3):449-456
We study the convergence of the Mann Iteration applied to the partial complement of a firmly nonexpansive operator with respect
to a linear subspace of a Hilbert space. A new concept considered here. A regularized version is also proposed. Furthermore,
to motivate this concept, some applications to robust regression procedures and location problems are proposed. 相似文献
43.
Abdellatif Fkyerat Martine Demeunynck Jean-Franois Constant Jean Lhomme 《Tetrahedron》1993,49(48):11237-11252
In the course of a program devoted to the synthesis of artificial endonucleases, we have previously reported a series of hybrid molecules in which a purine is linked to an intercalating drug by a polyamino chain. These molecules recognize and cleave selectively abasic sites in DNA with very high efficiency. In order to get insight into the mechanism of recognition and cleavage, we have prepared a new series of molecules in which the purine is linked to an amino-acridine by an aliphatic chain containing amido or/and amino groups. The key intermediates are -halo-ω-amino polyaza which may be of general use as linkers in bioconjugate chemistry. 相似文献
44.
The regioselective synthesis of two new acetylenic compounds, sterehirsutinal ( 1 ) and sterehirsutinol ( 2 ), isolated recently from culture medium of the fungus Stereum hirsutum, is reported. 相似文献
45.
Computational study of sulfur atom-transfer reactions from thiiranes to ER3 (E = As, P; R = CH3, Ph)
Computational estimates have been made for the P=S and As=S bond strengths in triphenylphosphine sulfide and triphenylarsine sulfide, on the basis of G3 calculations for the methyl analogues and isodesmic-exchange reactions. Also, with the performance of the G3 method level for related compounds taken into consideration, the best estimates are 82 and 68 kcal/mol, respectively. While the value for triphenylarsine sulfide is within 2 kcal/mol of the single experimental estimate, that for triphenylphosphine sulfide is lower by 6 kcal/mol. (Capps, K. B.; Wixmerten, B.; Bauer, A.; Hoff, C. D. Inorg. Chem. 1998, 37, 2861-2864.) Despite virtually identical electronegativities of P and As, it is found that there is greater charge separation in the P=S bond. It is found that S atom transfer from thiiranes to arsines is exothermic. 相似文献
46.
In this paper, first we discuss a technique to compare finite volume method and some well-known finite element methods, namely the dual mixed methods and nonconforming primal methods, for elliptic equations. These both equivalences are exploited to give us a posteriori error estimator for finite volume methods. This estimator is explicitly given, easy to compute and asymptotically exact without any regularity of the solution in unstructured grids. 相似文献
47.
Abdellatif Agouzal 《计算数学(英文版)》2000,18(6):639-644
1. IlltroductionThe finite element approximation of the convection--diffusin equations has been investigated using several different approaches (see e.g. [3] [4] and the references therein).Previous analysis in primal formulation of these problems was done for two types ofapproximation schemes: one which produces a continuous piecewise polynomial approximation and one which produces a piecewise polynomial approximation which arecontinuous for certain number of moments accross interelement edge… 相似文献
48.
Synthesis of Unprecedented Sulfonylated Phosphono‐exo‐Glycals Designed as Inhibitors of the Three Mycobacterial Galactofuranose Processing Enzymes
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Christophe J.‐M. Frédéric Dr. Abdellatif Tikad Jian Fu Dr. Weidong Pan Ruixiang B. Zheng Dr. Akihiko Koizumi Dr. Xiaochao Xue Prof. Todd L. Lowary Prof. Stéphane P. Vincent 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(44):15913-15920
This study reports a new methodology to synthesize exo‐glycals bearing both a sulfone and a phosphonate. This synthetic strategy provides a way to generate exo‐glycals displaying two electron‐withdrawing groups and was applied to eight different carbohydrates from the furanose and pyranose series. The Z/E configurations of these tetrasubstituted enol ethers could be ascertained using NMR spectroscopic techniques. Deprotection of an exo‐glycal followed by an UMP (uridine monophosphate) coupling generated two new UDP (uridine diphosphate)‐galactofuranose analogues. These two Z/E isomers were evaluated as inhibitors of UGM, GlfT1, and GlfT2, the three mycobacterial galactofuranose processing enzymes. Molecule 46‐(E) is the first characterized inhibitor of GlfT1 reported to date and was also found to efficiently inhibit UGM in a reversible manner. Interestingly, GlfT2 showed a better affinity for the (Z) isomer. The three enzymes studied in the present work are not only interesting because, mechanistically, they are still the topic of intense investigations, but also because they constitute very important targets for the development of novel antimycobacterial agents. 相似文献
49.
Debenzylative Cycloetherification: An Overlooked Key Strategy for Complex Tetrahydrofuran Synthesis
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Dr. Abdellatif Tikad Julien A. Delbrouck Prof. Stéphane P. Vincent 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(28):9456-9476
Tetrahydrofuran (THF) is a major structural feature found in many synthetic and natural products displaying a variety of biological properties. This review summarizes the main synthetic approaches that have been developed to construct tetrahydrofuran moieties involving debenzylative cycloetherification reactions (DBCE). Interestingly, this reaction is regio‐ and stereoselective without the requirement of a selective protection/deprotection strategy. Many applications of this process have been reported, including carbafuranoside synthesis, regioselective deprotection of the benzyl group positioned γ to an alkene, and total synthesis of natural products. The stereochemical outcome and the mechanism of these interesting transformations are also discussed. 相似文献
50.
In this Note we establish a Hölder stability estimate for an inverse pointwise source elliptic problem. 相似文献