排序方式: 共有146条查询结果,搜索用时 78 毫秒
41.
Enolizable Carbonyls and N,O‐Acetals: A Rational Approach for Room‐Temperature Lewis Superacid‐Catalyzed Direct α‐Amidoalkylation of Ketones and Aldehydes
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Bahria Touati Dr. Abderrahman El Bouakher Dr. Catherine Taillier Dr. Raja Ben Othman Prof. Dr. Malika Trabelsi‐Ayadi Dr. Sylvain Antoniotti Dr. Elisabet Duñach Prof. Dr. Vincent Dalla 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(17):6012-6022
An efficient catalytic room‐temperature direct α‐amidoalkylation of carbonyl donors, that is, ketones and aldehydes with unbiased N,O‐acetals, is described. Sn(NTf2)4 is an optimal catalyst to promote this challenging transformation at low loading and the reaction shows promising scope. A comprehensive and rational evaluation of this reaction has led to the establishment of an empirical scale of nucleophilic reactivity for a broad set of ketones that should be helpful in the synthetic design and development of carbonyl α‐functionalization methods. 相似文献
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Synthesis,characterization, and photovoltaic properties of dithienylbenzobisazole‐dithienylsilole copolymers
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Achala Bhuwalka Monique D. Ewan Jared F. Mike Moneim Elshobaki Brandon Kobilka Sumit Chaudhary Malika Jeffries‐EL 《Journal of polymer science. Part A, Polymer chemistry》2015,53(13):1533-1540
Three conjugated polymers comprised of dioctyl‐dithieno‐[2,3‐b:2',3'‐d]silole and a donor‐acceptor‐donor triad of either cis‐benzbisoxazole, trans‐benzobisoxazole or trans‐benzobisthiazole were synthesized via the Stille cross‐coupling reaction. The impact of varying the heteroatoms and/or the location within the benzobisazole moiety on the optical and electronic properties of the resulting polymers was evaluated via cyclic voltammetry and UV‐Visible spectroscopy. All of the polymers have similar optical band‐gaps of ~1.9 eV and highest occupied molecular orbital levels of ? 5.2 eV. However, the lowest unoccupied molecular orbitals (LUMO) ranged from ? 3.0 to ? 3.2 eV. Interestingly, when the polymers were used as donor materials in bulk‐heterojunction photovoltaic cells with PC71BM as the electron‐acceptor, the benzobisoxazole‐based polymers gave slightly better results than the benzobisthiazole‐containing polymers with power conversion efficiencies up to 3.5%. These results indicate that benzobisoxazoles are promising materials for use in OPVs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1533–1540 相似文献
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Mohamed Skiba Malika Lahiani-Skiba 《Journal of inclusion phenomena and macrocyclic chemistry》2013,75(3-4):341-349
The objective of this work was to optimize the synthesis procedure of soluble cyclodextrin polymers developed by Weltrowski et al. The use of the parameters indicated by the latter in our laboratory led to a lower result, which did not exceed 15 % (w/w). The new method resulted simultaneously in two fractions, a water soluble one and an insoluble one with a yield of 40 and 85 % (w/w), respectively. Only soluble cyclodextrin polymers were characterized along with the cytotoxicity study. The optimized soluble polymers were characterized by Fourier-Transform Infrared Spectrophotometer, Thermogravimetric Analyzer, Differential Scanning Calorimetry, Powder X-Ray Diffraction Analysis and Size Exclusion Chromatography. In vitro cytotoxicity against peritoneal macrophage cells of female CD1 mice showed that soluble poly-α-CD and poly-γ-CD were less cytotoxic than soluble poly-β-CD at small dose and the opposite was true at higher dose. In conclusion, temperature and time could be used to optimize the yield of polymer cyclodextrins, which will have a broad use in the drug delivery system. 相似文献
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Amel Bendjeddou Houria Djebbar Malika Berredjem Z'Hour Hattab Zine Regainia Nour-Eddine Aouf 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):1351-1362
A general synthesis for the preparation of chiral N-N′ substituted 1,2,5-thiadiazolidine 1,1-dioxides has been developed beginning with proteogenic amino acid, sulfuryl chloride, and dibromoethane. The selected chemistry and spectral properties of these compounds are examined. Overall, routes described are applicable to the synthesis of a variety of constrained dipeptidal sulfamides representing novel peptidomimetic scaffolds. 相似文献
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Malika Berredjem Zine Regaïnia Abdelghani Djahoudi Nour-Eddine Aouf Georges Dewynter Jean-Louis Montero 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):249-264
Abstract Les carboxylsulfamides sont obtenus à partir de l'isocyanate de chlorosulfonyle, d'amines primaires et d'α-hydroxyesters. Après réduction alcaline, ces carboxylsulfamides sont cyclisés dans les conditions de la réaction de Mitsunobu pour conduire aux N-sulfamoyloxazolidinones chides avec des rendements élevés. The synthesis of carboxylsulfamides was carried out starting from chlorosulfonyl isocyanate, primary amines and α-hydroxyesters. After reduction, the carboxylsulfamides were cyclised under Mitsunobu conditions giving N-sulfamoyloxazolidinones in good yields. 相似文献
46.
Rakhmankulova M Stavrou SW Yuen AP Zhou R Kessler P Pevsner PH 《Rapid communications in mass spectrometry : RCM》2008,22(15):2349-2354
Micropipette tip (tip) pipetting accuracy and precision are functions of tip manufacture consistency, morphological variation, and retained inner tip wall particulate matter. Irregular tip inner wall surfaces and retained particulate matter cause pipetting inaccuracy. Washed and unwashed tips from seven manufacturers were compared using weight by difference (six), microscopic Luxol Fast Blue staining (seven), and matrix-assisted laser desorption/onization time-of-flight (MALDI-TOF) mass spectrometry (six). Photomicrographs revealed tip irregularity and inner wall retained particulate matter. Computer model analysis was used to identify tip irregularity and retained matter. These tests established the utility of a pipette solvent wash to increase the performance and the accuracy of tips and, thus, improve the MALDI mass spectra obtained. 相似文献
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Bouzina Abdeslem Berredjem Malika Belhani Billel Bouacida Sofiane Marminon Christelle Le Borgne Marc Bouaziz Zouhair Aissaoui Mohamed 《Research on Chemical Intermediates》2021,47(4):1359-1376
Research on Chemical Intermediates - We demonstrate here a rapid and comfortable synthetic sequence to benzothiadiazinone dioxide (six-membered cyclic sulfamide) derivatives, analogues of... 相似文献
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Dr. Adina Borbély Dr. Fabien Thoreau Dr. Eduard Figueras Malika Kadri Dr. Jean-Luc Coll Dr. Didier Boturyn Prof. Dr. Norbert Sewald 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(12):2602-2605
The effective delivery of cytotoxic agents to tumor cells is a key challenge in anticancer therapy. Multivalent integrinspecific ligands are considered a promising tool to increase the binding affinity, selectivity, and internalization efficiency of small-molecule drug conjugates. Herein, we report the synthesis and biological evaluation of a multimeric conjugate containing the high-affinity integrin αvβ3 binding ligand RAFT-c(RGDfK)4, a lysosomally cleavable Val-Cit linker, and cryptophycin-55 glycinate, a potent inhibitor of tubulin polymerization. In vitro cytotoxicity assays verified that the multimeric RGD-cryptophycin conjugate displays improved potency compared to the monomeric analogue in integrin αvβ3 overexpressing tumor cell lines, while significantly reduced activity was observed in the integrin-negative cell line. 相似文献
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