排序方式: 共有149条查询结果,搜索用时 15 毫秒
41.
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
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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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Marc Dubois Belto Dieudonné Adel Mesbah Pierre Bonnet Malika El-Ghozzi Guillaume Renaudin Daniel Avignant 《Journal of solid state chemistry》2011,184(1):220-226
The unusual oxidation state +3 of the thorium has been stabilized into a lithium containing non-stoichiometric mixed-valence (III/IV) thorium fluorinated phase with formula Li2+xTh12F50 (0<x<1.8). This phase is closely related to the Li5.5Ce12F50 one, the structure of which has been determined from the combined single-crystal X-ray diffraction and high resolution synchrotron powder diffraction. In these phases, the Li+ ions can be divided into two groups and are located either in locked positions or in open channels of the three dimensional framework. The amount of Li+ ions in open channels can be variable, so that the afore mentioned single phase may be considered as an insertion compound. The Li+ insertion is accompanied by the simultaneous reduction of a part of the Th4+ ions, resulting in a mixed-valence III/IV thorium fluoride. The electrochemical insertion of Li+ ions into the open channels of the host matrix has been carried out at 60 °C, using an alkylcarbonate PC-LiClO4 1 M electrolyte. The Li+ and Th3+ contents, both in the starting composition and the Li+ inserted ones, were investigated by high resolution solid state 7Li NMR and EPR, respectively. 相似文献
48.
M'Hamed Esseffar Malika El Messaoudi Widad Bouab 《Journal of Physical Organic Chemistry》2009,22(10):913-918
Intermolecular charge‐transfer (CT) spectra of 3‐thioxo‐5‐oxo‐, 5‐thioxo‐3‐oxo‐, and 3,5‐dithioxo‐ derivatives of 2,7‐dimethyl‐[1,2,4]‐triazepine 1:1 molecular complexes with molecular iodine were studied in the UV‐visible region. Equilibrium constants and free energy changes of the formed complexes were determined in solution. Ab initio calculations at HF/LANL2DZ* and MP2/LANL2DZ* were carried out to establish the nature of the complexation site, to determine the complex structures, and to examine the basicity of these compounds toward molecular iodine. The 3,5‐dithioxo‐2,7‐dimethyl‐[1,2,4]‐triazepine is the most basic one toward molecular iodine. In all cases, the complexation takes place at the heteroatom attached to position 3 of the triazepine. Hence, although in general, thiocarbonyls are stronger bases than carbonyls in the gas phase, 5‐thioxo‐2,7‐dimethyl‐[1,2,4]‐triazepin‐3‐one behaves as an oxygen base towards I2. Experimental free energies in solution and gas‐phase computational values are linearly correlated. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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A stereoselective synthesis of pentacyclic steroids has been achieved. Starting from commercially available cholic acid 1, followed by asymmetric epoxidation and by stereoselective epoxide ring opening, employing nucleophilic species, the corresponding products were afforded in good yields. The compounds were being evaluated for their biological activity. 相似文献
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