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81.
Ighilahriz K Boutemeur B Chami F Rabia C Hamdi M Hamdi SM 《Molecules (Basel, Switzerland)》2008,13(4):779-789
We have investigated a microwave-assisted synthesis of 4(3H)-quinazolinones by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines,using Keggin-type heteropolyacids (H(3)PW(12)O(40).13H(2)O, H(4)SiW(12)O(40).13H(2)O,H(4)SiMo(12)O(40).13H(2)O or H(3)PMo(12)O(40).13H(2)O) as catalysts. We found that the the use of H(3)PW(12)O(40).13H(2)O acid coupled to microwave irradiation allows a solvent-free, rapid (approximately 13min) and high-yielding reaction. 相似文献
82.
A series of pyrazolo[4,3-e][1,2,4]triazolo[4,3-c]pyrimidines were prepared via oxidative cyclization of aldehyde N-(1,3-diphenylpyrazolo[3,4-d]pyrimidin-4-yl)hydrazones. Dimroth rearrangement of such a series yielded pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidines. 相似文献
83.
Hamdi Ben Halima Abdelhamid Errachid Nicole Jaffrezic-Renault 《Electroanalysis》2023,35(1):e202100451
The review presents advances and main challenges of the affinity sensors based on field- effect transistors published during the last five years. The different nanomaterial-based field-effect transistors are classified according to the nature of the nanomaterials, beginning by silicon, the “gold-standard” semiconductor, the gallium nitride semiconductor, the organic semiconductors, the silicon nanowires, the inorganic nanomaterials, the carbon nanotubes and the graphene. Due to its exceptional electrical properties, the main works are devoted to graphene. The obtained analytical performances for the detection of biomarkers, of DNA sequences and of miRNA are listed. The relation between the operational conditions - nature of the nanomaterials, procedure of preparation, choice of the receptor molecule, method of immobilization – and the analytical performance are discussed. The perspective of industrialization of these affinity sensors based on field-effect transistors is discussed. 相似文献
84.
Ali Akbar Fathi Mohammad Reza Afshar Mogaddam Saeed Mohammad Sorouraddin Mir Ali Farajzadeh Ali Mohebbi 《Journal of separation science》2023,46(17):2201055
This research aims to synthesize a specific and efficient sorbent to use in the extraction of apixaban from human plasma samples and its determination by high-performance liquid chromatography-tandem mass spectrometry. High specific surface area of metal-organic framework, magnetic property of iron oxide nanoparticles, selectively of molecular imprinted polymer toward the analyte, and the combination of dispersive solid-phase extraction method with a sensitive analysis system provided an efficient analytical method. In this study, first, a molecularly imprinted polymer combined with magnetic metal organic framework nanocomposite was prepared and then characterized using different techniques. Then the sorbent particles were used for selective extraction of the analyte from plasma samples. The efficiency of the method was improved by optimizing effective parameters. According to the validation results, wide linear range (1.02–200 ng mL−1), acceptable coefficient of determination (0.9938), low limit of detection (0.32 ng mL−1) and limit of quantification (1.02 ng mL−1), high extraction recovery (78%), and good precision (relative standard deviations ≤ 2.9% for intra- (n = 6) and interday (n = 6) precisions) were obtainable using the proposed method. These outcomes showed the high potential of the proposed method for screening apixaban in the human plasma samples. 相似文献
85.
Single crystal of a new organic–inorganic hybrid material [C6H10(NH3)2]3CuBr4.3Br was synthesized by the slow evaporation method at room temperature and characterized by X-ray diffraction, FTIR, Raman spectroscopy, UV–Vis, dielectric measurements, and Hirschfield surface analysis. The title compound crystallizes in trigonal system \( P\overline{3} \).The crystal packing is governed by the N-H…Br and non-classical C-H…Br hydrogen-bonding interactions between the 1, 2-diamoniumcyclohexane cations, the tetrahedral [CuBr4]3? anions, and the isolated ion Br?. Theoretical calculations were performed using density functional theory (DFT) for studying the molecular structure, vibrational spectra, and optical properties of the investigated molecule in the ground state. The optimized geometrical parameters obtained by DFT calculations are in good agreement with single crystal XRD data. The optical properties were investigated by optical absorption and show two bands at 260 and 305 nm. 相似文献
86.
Badri Z. Momeni Nastaran Fathi Maliheh Shafiei Fahimeh Ghasemi Frank Rominger 《Journal of Coordination Chemistry》2016,69(18):2697-2706
The reaction of a mixture of cis and trans-[PtCl2(SMe2)2] with 4,7-phen (4,7-phen = 4,7-phenanthroline) in a molar ratio of 1 : 1 or 2 : 1 resulted in the formation of mono and binuclear complexes trans-[PtCl2(SMe2)(4,7-phen)] (1) and trans-[Pt2Cl4(SMe2)2(μ-4,7-phen)] (2), respectively. The products have been fully characterized by elemental analysis, 1H, 13C{1H}, HHCOSY, HSQC, HMBC, and DEPT-135 NMR spectroscopy. The crystal structure of 1 reveals that platinum has a slightly distorted square planar geometry. Both chlorides are trans with a deviation from linearity 177.66(3)°, while the N–Pt–S angle is 175.53(6)°. Similarly, the reaction of a mixture of cis and trans-[PtBr2(SMe2)2] with 4,7-phen in a 1 : 1 or 2 : 1 mole ratio afforded the mono or binuclear complexes trans-[PtBr2(SMe2)(4,7-phen)] (3) and trans-[Pt2Br4(SMe2)2(μ-4,7-phen)] (4), respectively. The crystal structure of trans-[Pt2Br4(SMe2)2(μ-4,7-phen)].C6H6 reveals that 4,7-phen bridges between two platinum centers in a slightly distorted square planar arrangement of the platinum. In this structure, both bromides are trans, while the PtBr2(SMe2) moieties are syn to each other. NMR data of mono and binuclear complexes of platinum 1–4 show that the binuclear complexes exist in solution as a minor product, while the mononuclear complexes are major products. 相似文献
87.
Behery FA Naeem ZE Maatooq GT Amer MM Wen ZH Sheu JH Ahmed AF 《Chemical & pharmaceutical bulletin》2007,55(8):1264-1266
The novel natural product juncutol (1), 1,4,7-trimethyl-8,9-dihydro-4H-cyclopenta[def]phenanthrene-2,6-diol, along with the three related metabolites juncusol (2), dehydrojuncusol (3), and 6-hydroxymethyl-1-methyl-5-vinyl-9,10-dihydrophenanthrene-2-ol (4), were isolated from the rhizomes of Juncus acutus L. (Juncaceae) growing in Egypt. The structural identity of 1 was determined on the basis of spectroscopic analyses, including 2D NMR spectroscopy. The inhibitory effect of these natural products on the expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide-stimulated RAW264.7 macrophage cells was determined for the first time. The unprecedented symmetrical compound juncutol (1) was found to be the most potent inhibitor against the induction of the proinflammatory iNOS protein. 相似文献
88.
Fathi A. Abu‐Shanab A. M. Hessen S. A. S. Mousa 《Journal of heterocyclic chemistry》2007,44(4):787-791
89.
On Rearrangements by Cyclialkylations of Arylpentanols to 2,3‐Dihydro‐1 H ‐indene Derivatives. Part 4. The Acid‐Catalyzed Cyclialkylation of 2,4‐Dimethyl‐2‐phenyl[3‐ 13 C]pentan‐3‐ol The cyclialkylation of 2,4‐dimethyl‐2‐phenyl[3‐13C]pentan‐3‐ol ( 4 ) gives only 2,3‐dihydro‐1,1,2,3‐tetramethyl‐1H‐[3‐13C]indene ( 6 ) (cf. Scheme 2) and not a trace of the isotopomeric 2,3‐dihydro‐1,1,2,3‐tetramethyl‐1H‐[2‐13C]indene ( 5 ). The mechanism proposed in [3] for the cyclialkylation of 4 (cf. Scheme 2, Path A) has, therefore, to be abandoned. The mechanism of Scheme 2, Path B, is proposed and may be considered as definitively established. 相似文献
90.
This paper investigates quasi-periodic vibration-based energy harvesting in a delayed nonlinear MEMS device consisting of a delayed Mathieu–van der Pol–Duffing type oscillator coupled to a delayed piezoelectric coupling mechanism. We use the multiple scales method to approximate the quasi-periodic response and the related power output near the principal parametric resonance. The effect of time delay on the energy harvesting performance is studied. It is shown that for appropriate combination of time delay parameters, there exists an optimum range of excitation frequency beyond the resonance where quasi-periodic vibration-based energy harvesting is maximum. Numerical simulations are performed to confirm the analytical predictions. 相似文献