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211.
Mohamed Ali Elsayed Khalifa Ezzat Mohamed Zayed Mona Hassan Mohamed Mohamed Hilmy Elnagdi 《Journal of heterocyclic chemistry》1983,20(6):1571-1573
A novel synthesis of pyrazine derivatives from the reaction of α-tosyloximinonitriles with several active methylene enaminonitrile derivatives is reported. The reaction sequence is discussed. 相似文献
212.
213.
Summary The bis-adducts formed by nickel(II) and zinc(II) chelates of 3-cyano-4-aryl-6-phenyl pyridine-2-(1H)thiones with pyridine and N-methylimidazole have been prepared and characterized by microelemental analyses, i.r., u.v., vis., and 1Hn.m.r. spectra and magnetic measurements. Owing to Lewis acid-base interactions, the diamagnetic square planar nickel(II) or zinc(II) chelates interact with two molecules of pyridine or N-methylimidazole in the two axial positions forming the corresponding octahedral bis-adducts. 相似文献
214.
A simple, rapid, and reliable method is given for determination of As(III) based on arsenite reduction of alcoholic iodine and titration of the equivalent iodide with Hg(II) using silver amalgam as the indicator electrode. Arsenite reduction is applied to the estimation of lead in minium, manganese in duralumin, chromium in zinc chromate, and vanadium and chromium in ilmenite, the excess of arsenite being determined by the same method used for As(III). The endpoints are accurately determined with very satisfactory potential breaks. 相似文献
215.
N. M. Khalifa E. S. Nossier M. A. Al-Omar A. E. Amr 《Russian Journal of General Chemistry》2016,86(2):400-405
A series of novel dihydro-alkylthio-benzyloxopyrimidine (S-DABO) and 1-[(2-hydroxyethoxy) methyl]-6-(phenylthio)thymine (HEPT) analogs bearing a (benzo[d]thiazol-2-yl)methyl moiety at the C6 position of the pyrimidine core have been synthesized. 5-Allyl-6-{(benzo[d]thiazol-2-yl)methyl}-2-thiouracil and 5-allyl-6-{(benzo-[d]thiazol-2-yl)methyl}uracil were alkylated to give, respectively, S2- and N1- ethoxymethyl and -methylthiomethyl uracil derivatives. 5-Allyl-6-[(benzo[d]thiazol-2-yl)methyl]-2-thiouracil was also alkylated by S2 with methyl bromoacetate and hydrolyzed to the corresponding acid. 相似文献
216.
N. O. Khalifa H. M. Widatallah A. M. Gismelseed F. N. Al-Mabsali R. G. S. Sofin M. Pekala 《Hyperfine Interactions》2016,237(1):46
Single-phased nanocrystalline particles of pure and 10 % Ti 4+-doped perovskite-related YFeO 3were prepared via mechanosynthesis at 450°C. This temperature is ~150–350 °C lower than those at which the materials, in bulk form, are normally prepared. Rietveld refinements of the X-ray diffraction patterns reveal that the dopant Ti 4+ ions prefer interstitial octahedral sites in the orthorhombic crystal lattice rather than those originally occupied by the expelled Fe 3+ ions. Magnetic measurements show canted antiferromagnetism in both types of nanoparticles. Doping with Ti 4+ lowers the Néel temperature of the YFeO 3 nanoparticles from ~ 586 K to ~ 521 K. The Ti 4+-doped YFeO 3 nanoparticles exhibit enhanced magnetization and coercivity but less magnetic hyperfine fields relative to the un-doped nanoparticles. The 57Fe Mössbauer spectra show ~ 15 % of the YFeO 3 nanoparticles and ~22 of Ti 4+-doped YFeO 3 ones to be superparamagnetic with blocking temperatures < 78 K. The broadened magnetic components in the 57Fe Mössbauer spectra suggest size-dependent hyperfine magnetic fields at the 57Fe nuclear sites and were associated with collective magnetic excitations. The 57Fe Mössbauer spectra show the local environments of the Fe 3+ ions in the superparamagnetic nanoparticles to be more sensitive to the presence of the Ti 4+ ions relative to those in the larger magnetic nanoparticles. 相似文献
217.
Russian Journal of General Chemistry - A series of novel S-DABO analogues bearing thiazolo[3,2-a]pyrimidine and pyrimido[2,1-b][1,3]thiazine has been developed starting from... 相似文献
218.
Reham Maher Ziad Khalifa Abla Ahmed Hathoot Magdi Abdel Azzem 《Electroanalysis》2023,35(4):e202200225
In this article, poly(1,2-diaminoanthraquinone) (pDAAQ) and poly(1,5-diaminonaphthalene) (pDAN) were electrochemically deposited layer by layer on a glassy carbon electrode (GCE) to generate pDAAQ/pDAN@GCE and pDAN/pDAAQ@GCE composite electrodes, respectively. The morphology and characteristics of the modified electrodes were investigated via electrochemical impedance spectroscopy)EIS), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy)SEM). The obtained results reveal the outstanding performance of the pDAN/pDAAQ@GCE electrode for electrochemical nitrite sensing where pDAAQ plays a vital role as the inner layer. Cyclic voltammetry (CV), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV) measurements revealed that the oxidation peak current of nitrite was proportional to its concentration. The best LSV results were obtained in a concentration range of 10–150 μM, with a limit of detection of 1.2 μM. Furthermore, the pDAN/pDAAQ@GCE composite electrode was used to determine nitrite ions in real water samples with good results. 相似文献
219.
Nourhan M. Abd El-Aziz Ibrahim Khalifa Amira M. G. Darwish Ahmed N. Badr Huda Aljumayi El-Sayed Hafez Mohamed G. Shehata 《Molecules (Basel, Switzerland)》2022,27(9)
COVID-19 is still a global pandemic that has not been stopped. Many traditional medicines have been demonstrated to be incredibly helpful for treating COVID-19 patients while fighting the disease worldwide. We introduced 10 bioactive compounds derived from traditional medicinal plants and assessed their potential for inhibiting viral spike protein (S-protein), Papain-like protease (PLpro), and RNA dependent RNA polymerase (RdRp) using molecular docking protocols where we simulate the inhibitors bound to target proteins in various poses and at different known binding sites using Autodock version 4.0 and Chimera 1.8.1 software. Results found that the chicoric acid, quinine, and withaferin A ligand strongly inhibited CoV-2 S -protein with a binding energy of −8.63, −7.85, and −7.85 kcal/mol, respectively. Our modeling work also suggested that curcumin, quinine, and demothoxycurcumin exhibited high binding affinity toward RdRp with a binding energy of −7.80, −7.80, and −7.64 kcal/mol, respectively. The other ligands, namely chicoric acid, demothoxycurcumin, and curcumin express high binding energy than the other tested ligands docked to PLpro with −7.62, −6.81, and −6.70 kcal/mol, respectively. Prediction of drug-likeness properties revealed that all tested ligands have no violations to Lipinski’s Rule of Five except cepharanthine, chicoric acid, and theaflavin. Regarding the pharmacokinetic behavior, all ligand predicted to have high GI-absorption except chicoric acid and theaflavin. At the same way chicoric acid, withaferin A, and withanolide D predicted to be substrate for multidrug resistance protein (P-gp substrate). Caffeic acid, cepharanthine, chicoric acid, withaferin A, and withanolide D also have no inhibitory effect on any cytochrome P450 enzymes. Promisingly, chicoric acid, quinine, curcumin, and demothoxycurcumin exhibited high binding affinity on SARS-CoV-2 target proteins and expressed good drug-likeness and pharmacokinetic properties. Further research is required to investigate the potential uses of these compounds in the treatment of SARS-CoV-2. 相似文献
220.
Mohamed E. Khalifa Adil A. Gobouri Fahad M. Kabli Tariq A. Altalhi Abdulraheem S. A. Almalki Amira M. Elemshaty 《Journal of heterocyclic chemistry》2019,56(4):1426-1436
Various novel benzimidazole entities linked to pyrazolyl and hydrazonoyl cyanide substrates carrying aryl and heteroaryl groups ( 8a – e to 10a – e ) were synthesized using new route syntheses and were focused on their pharmacological evaluation as one of the most important factors for the determination of the activity of these synthesized compounds. The obtained benzimidazoles' series were fully characterized and exhibited remarkable pharmacological activity upon in vitro screening for their antibacterial activity against strains of selected pathogenic Gram‐positive bacteria (Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli) comparing with Ampicillin and Kanamycin as standard antibacterial agents and against human liver cancer cell lines (HepG2) as antitumor agents as well. 相似文献