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161.
Chemical reactivity of 2-methyl-2-phenyl-1,3-oxathiolan-5-one (1) toward various reagents such as hydroxyaldehyde, ketone, α,β unsaturated carbonyl compounds, heterocyclic amine, hydrazine, and hydrazide to give unpredicative opened and fused heterocyclic systems was investigated. Moreover, treatment of compound 1 with bromoester to afford the respective fused system, 2-methyl-2-phenylfuro[3,2-d][1,3]oxathiol-5(6H)-one (6) was implemented. Besides, 1H–1H nuclear overhauser effect spectroscopy was used for full confirmation of the compound 19. In addition, the density functional theory modeling study outcomes were discussed and all of the new synthesized compounds were evaluated as antioxidants and cytotoxicity assay against hepatocellular carcinoma cell line. 相似文献
162.
Awatef Ayadi Amani Jaafar Adeline Fix-Tailler Ghassan Ibrahim Gérald Larcher Abdelkrim El-Ghayoury 《Tetrahedron》2017,73(25):3554-3563
The synthesis of two tetrathiafulvalene-appended pyridinehydrazone pyrimidine ligands, namely (Z)-4-(2-((5-([2,2′-bi(1,3-dithiolylidene)]-4-yl)pyridin-2-yl)methylene) hydrazinyl)-6-chloropyrimidine L1 and (Z)-4-(2-((6-([2,2′-bi(1,3-dithiolylidene)]-4-yl)pyridin-2-yl)methylene) hydrazinyl)-6-chloropyrimidine L2 is described. Ligand L1 was reacted with cobalt(II) to yield a cationic metal complex [Co(L1)2] while ligand L2 was reacted with zinc(II) to afford a neutral metal complex [ZnL2Cl2]. The crystal structure analysis of [Co(L1)2] indicate that Co(II) ion is coordinated by six nitrogen atoms from two perpendicular ligands while in [ZnL2Cl2], Zn(II) is coordinated by two chlorine atoms and three nitrogen atoms. The electrochemical behavior indicate that ligands L1 and L2 and the zinc(II) complex are suitable fort the preparation of crystalline radical cation salts. Finally the determination of MIC80 values against C. albicans, C. glabrata, C. parapsilosis, C. krusei and E. dermatitidis revealed that the cobalt(II) metal complex [Co(L1)2] is active against all the studied fungi. 相似文献
163.
Mansur B. Ibrahim Rami Suleiman Mohammed Fettouhi Bassam El Ali 《Transition Metal Chemistry》2017,42(1):1-8
A palladium(II)-bis(oxazoline) complex supported on silica (Pd-BOX-Si) was prepared, characterized and applied as a catalyst in Mizoroki–Heck cross-coupling reactions. The bis(oxazoline) (BOX) ligand has a hydroxyl group that can be anchored to 4-benzyl chloride-functionalized silica gel, followed by the coordination of palladium(II) chloride. The catalytic activity and the recyclability of Pd-BOX-Si have been investigated in the production of cinnamic acid derivatives via Mizoroki–Heck coupling reactions of acrylates with aryl halides; The Pd-BOX-Si catalyst demonstrated excellent catalytic activity. Characterization of the recycled Pd-BOX-Si catalyst revealed its good stability under the reaction conditions employed. 相似文献
164.
—An analysis of non-linear flutter of a simply-supported panel exposed to supersonic gas flow and random in-plane forces is presented for two- and three-mode interactions. A first order quasi-steady state aerodynamic piston theory is used to model the aerodynamic loading. The Fokker-Planck equation is used to derive a general moment equation for two- and three-mode interactions. For stability analysis the moment equation is consistent and the mean square stability boundaries of the equilibrium are obtained in terms of the system parameters. The stability boundaries reveal common features to those predicted by the deterministic theory of panel nutter. For the non-linear response the moment equation is found inconsistent and a cumulant-neglect closure is used by setting cumulants of fifth and sixth orders to zero. This first order non-Gaussian closure is carried out to solve for the response statistics in terms of the air-to-plate mass ratio, aerodynamic pressure, modal damping, and in-plane random force spectral density. It is found that the non-Gaussian solution yields higher levels for the response statistics than those obtained by the Gaussian solution. The inclusion of more modes results in a reduction of the response levels and expands the stability region. 相似文献
165.
Alaa S. Amin Ibrahim S. Ahmed Hassan A. Dessouki Hassan A. Mohamed 《Chemical Papers》2010,64(3):278-284
Simple and rapid spectrophotometric methods have been developed for the microdetermination of fluoxetine HCl. The proposed
methods are based on the formation of ion-pair complexes between fluoxetine and bromophenol blue (BPB), bromothymol blue (BTB),
bromocresol green (BCG), and bromocresol purple (BCP) which can be measured at optimum λmax. Optimization of reaction conditions was investigated. Beerșs law was obeyed in the concentration ranges of 0.5–8.0 μg mL−1, whereas optimum concentration as adopted from the Ringbom plots was 0.7–7.7 μg mL−1. The molar absorptivity, Sandell sensitivity, and detection limit were also calculated. The most optimal and sensitive method
was developed using BCG. The correlation coefficient was 0.9988 (n = 6) with a relative standard deviation of 1.25, for six determinations of 4.0 μg mL−1. The proposed methods were successfully applied to the determination of fluoxetine hydrochloride in its dosage forms and
in biological fluids (spiked plasma sample) using the standard addition technique. 相似文献
166.
Chen Z Chen W Yuan B Xiao L Liu D Jin Y Quan B Wang JO Ibrahim K Wang Z Zhang W Jiang X 《Langmuir : the ACS journal of surfaces and colloids》2010,26(23):17790-17794
This report establishes an in vitro model on glass surfaces for patterning multiple types of cells to simulate cell-cell interactions in vivo. The model employs a microfluidic system and poly(ethylene glycol)-terminated oxysilane (PEG-oxysilane) to modify glass surfaces in order to resist cell adhesion. The system allows the selective confinement of different types of cells to realize complete confinement, partial confinement, and no confinement of three types of cells on glass surfaces. The model was applied to study intercellular interactions among human umbilical vein endothelial cells (HUVEC), PLA 801 C and PLA801 D cells. 相似文献
167.
Mohamed M. Ibrahim Abd El-Motaleb. M. Ramadan 《Journal of inclusion phenomena and macrocyclic chemistry》2010,68(3-4):287-296
Two new artificial peptides with histidine side chains, namely N-methyl N,N′-bis(Im-bzl-l-histidylmethylestermethyl)amine L1 and N,N′,N″,N?-tetrakis(Im-bzl-l-histidylmethyl-estermethyl)ethylene diamine L2 have been synthesized and were shown to form stable zinc complexes [L1Zn(H2O)2](ClO4)2 1 and [L2Zn2(H2O)3](ClO4)4 2, respectively. Solution studies (pH–1NMR titrations) of the ligand L2 in the presence of zinc ions were also reported. The catalytic activity of zinc complex species 1 and 2 as structural phosphotriestrase models were tested on the hydrolysis/detoxification of p-nitrohenl diphenylphosphate (p-NPDPP). From the correlation between the pH-rate profiles and the species distribution curves, the catalytically active species could be identified. On the basis of R-dependence as well as the rate acceleration of each complex, the possibility of cooperative action of zincs in dinuclear zinc complex is debated. 相似文献
168.
N. A. Halim Z. A. Ibrahim A. B. Ahmad 《Journal of Thermal Analysis and Calorimetry》2010,102(3):983-988
The high potential for intercalations by water and various guest molecules is induced by the exchangeable cation inside Ca2+–Montmorillonite gallery. XRD peak for Mon at 2θ = 6.04° (d
001 = 1.462 nm) shows the structural effect on the clay gallery influenced by the intercalated water layers. Further increases
in the gallery height are observed with the intercalation of octadecyl ammonium cations in OMON (d
001 = 1.840 nm) and ENR-50 matrix chains in CENR-50 (d
001 = 1.954 nm). DSC studies on the other hand reveal the thermal behaviors of intercalated molecules that are linked to the
exchangeable cations. The endothermic of Ca2+–Montmorillonite (H
Mon = 356.3 J/g) in low temperature range (30–100 °C) indicates the removal of free water and hydrogen bonded water molecules,
while the endothermic around 150 °C is related to the induced skeletal layer of water within Ca2+–Montmorillonite. The OMON endothermic (H
OMON = 47.0 J/g, T
m = 36.94 °C) tells that cation exchange had modified the water structures and content inside the renewed clay. The intercalation
of ENR-50 chains into OMON gallery reveals two endothermic with the T
m1 and T
m2 are at 86.24 and 113.80 °C, respectively. These T
ms confirm that the alkyl chain segment on octadecyl ammonium cation occupy the OMON interlayer space. 相似文献
169.
Mohd Marsin Sanagi Mazidatulakmam Miskam Wan Aini Wan Ibrahim Dadan Hermawan Hassan Y. Aboul‐Enein 《Journal of separation science》2010,33(14):2131-2139
A three‐phase hollow fiber liquid‐phase microextraction method coupled with CE was developed and used for the determination of partition coefficients and analysis of selected nitrophenols in water samples. The selected nitrophenols were extracted from 14 mL of aqueous solution (donor solution) with the pH adjusted to pH 3 into an organic phase (1‐octanol) immobilized in the pores of the hollow fiber and finally backextracted into 40.0 μL of the acceptor phase (NaOH) at pH 12.0 located inside the lumen of the hollow fiber. The extractions were carried out under the following optimum conditions: donor solution, 0.05 M H3PO4, pH 3.0; organic solvent, 1‐octanol; acceptor solution, 40 μL of 0.1 M NaOH, pH 12.0; agitation rate, 1050 rpm; extraction time, 15 min. Under optimized conditions, the calibration curves for the analytes were linear in the range of 0.05–0.30 mg/L with r2>0.9900 and LODs were in the range of 0.01–0.04 mg/L with RSDs of 1.25–2.32%. Excellent enrichment factors of up to 398‐folds were obtained. It was found that the partition coefficient (Ka/d) values were high for 2‐nitrophenol, 3‐nitrophenol, 4‐nitrophenol, 2,4‐dinitrophenol and 2,6‐dinitrophenol and that the individual partition coefficients (Korg/d and Ka/org) promoted efficient simultaneous extraction from the donor through the organic phase and further into the acceptor phase. The developed method was successfully applied for the analysis of water samples. 相似文献
170.