排序方式: 共有18条查询结果,搜索用时 31 毫秒
1.
Djamila Hikem‐Oukacha Maamar Hamdi Artur M. S. Silva Rachedi Yahia 《Journal of heterocyclic chemistry》2011,48(1):63-68
3‐(Bromoacetyl)‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one was synthesized by the reaction of dehydroacetic acid (DHAA) with bromine in glacial acetic acid. Novel heterocyclic products were synthesized from the reaction of bromo‐DHAA with alkanediamines, phenylhydrazines, ortho‐phenylenediamines, and ortho‐aminobenzenethiol. The obtained new products 3‐(2‐N‐substituted‐acetyl)‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐ones, 4‐hydroxy‐3‐[1‐hydroxy‐2‐(2‐phenylhydrazinyl)vinyl]‐6‐methyl‐2H‐pyran‐2‐one, 1‐(2,4‐dinitrophenyl)‐7‐methyl‐2,3‐dihydro‐1H‐pyrano[4,3‐c]pyridazine‐4,5‐dione, 3‐(3,4‐dihydroquinoxalin‐2‐yl)‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one/3‐(3,4‐dihydroquinoxalin‐2‐yl)‐6‐methyl‐2H‐pyran‐2,4(3H)‐dione, 6‐methyl‐3‐(3,4‐dihydroquinoxalin‐2‐yl)‐2H‐pyran‐2,4(3H)‐dione, and (E)‐3‐(2H‐benzo[b][1,4]thiazin‐3(4H)‐ylidene)‐6‐methyl‐2H‐pyran‐2,4(3H)‐dione were fully characterized by IR, 1H and 13C NMR, and mass spectra. J. Heterocyclic Chem., 2011. 相似文献
2.
Ouerdia Megherbi Hamid Hamiche Saïd Djennoune Maamar Bettayeb 《Nonlinear dynamics》2017,90(3):1519-1533
In this paper, we discuss and investigate the impulsive synchronization of fractional-order discrete-time chaotic systems. The proposed method is based on the impulsive synchronization theory used in the integer-order case on the one hand and the mathematical analysis of the fractional-order discrete-time systems on the other hand. Sufficient conditions for the stability of synchronization error system are given, and application example with numerical simulations is illustrated in order to verify that the proposed method is applicable and effective. Furthermore, in order to validate the proposed synchronization approach, we have also provided the experimental implementation results using Arduino Mega boards. 相似文献
3.
Bellara Nedjar Maamar Hamdi Jacques Pri Valentin Hrault 《Journal of heterocyclic chemistry》1978,15(7):1153-1158
The multistep catalytic reduction of 6-methyl-4-hydroxy-2-pyrone allows isolation of two intermediate compounds: the biologically active parasorbic acid ( 5 ) and the 6-methyl-5,6-dihydro-4-hydroxy-2-pyrone ( 2 ). The desmotropic keto-enol equilibrium lies on the enol side, with the 4rhydroxy structure. Primary arylamines readily react with 2 , leading to corresponding 2-pyridones 8 ; with methylamine, the aliphatic intermediate 7 resulting from ring attack at the 2 position can be isolated. Also further functionnalization of both dihydropyrone and 2-pyridone is possible by selective bromination at position 3. 相似文献
4.
5.
Sami Ben Maamar Natsagma Jadambaa Francis Vocanson Faouzi Meganem Isabelle Dumazet-Bonnamour 《Supramolecular chemistry》2013,25(6):450-454
New thiacalix[4]arenes appended with three amide functions have been prepared. Their conformations have been solved thanks to 1H NMR 2D correlation spectroscopy (COSY) and nuclear overhauser and exchange spectroscopy (NOESY). The complexation ability of these ligands towards various metal ions (Cd2 + , Pb2 + , Pd2 + , Ni2 + , Hg2 + , Hg+, Ag+, Zn2 + and Cu2 + ) has been investigated by the UV–vis absorption and the stoichiometry of the metal–ligand complexes was determined. 相似文献
6.
AlShabi Mohammad Ghenai Chaouki Bettayeb Maamar Ahmad Fahad Faraz El Haj Assad Mamdouh 《Journal of Thermal Analysis and Calorimetry》2021,144(5):1655-1670
Journal of Thermal Analysis and Calorimetry - The use of photovoltaic (PV) solar systems as a direct convertor of electricity is increasing on daily basis at industrial and domestic scales. Such... 相似文献
7.
Tessier C Suhard D Rebière F Souidi M Dublineau I Agarande M 《Microscopy and microanalysis》2012,18(1):123-133
For a few years, the biological effects on ecosystems and the public of the bioaccumulation of radionuclides in situations of chronic exposures have been studied. This work, in keeping with the ENVIRHOM French research program, presents the uranium microdistribution by secondary ion mass spectrometry (SIMS) technique in the renal cortex of rats following chronic exposure to this low level element in the drinking water (40 mg/L) as a function to exposure duration (6, 9, 12, and 18 months). The SIMS mass spectra and 238U+ ion images produced with a SIMS CAMECA 4F-E7 show the kinetic of uranium accumulation in the different structures of the kidney. For the rats contaminated up to 12 months, the radioelement is mainly fixed in the proximal tubules; then after 18 exposure months, uranium is detected in all the segments of the nephron. This work has also shown that ion microscopy is an analytical method to detect trace elements and give elemental cartography at the micrometer scale. 相似文献
8.
9.
Robust Stabilization and Synchronization of a Novel Chaotic System with Input Saturation Constraints
Ahmad Taher Azar Fernando E. Serrano Quanmin Zhu Maamar Bettayeb Giuseppe Fusco Jing Na Weicun Zhang Nashwa Ahmad Kamal 《Entropy (Basel, Switzerland)》2021,23(9)
In this paper, the robust stabilization and synchronization of a novel chaotic system are presented. First, a novel chaotic system is presented in which this system is realized by implementing a sigmoidal function to generate the chaotic behavior of this analyzed system. A bifurcation analysis is provided in which by varying three parameters of this chaotic system, the respective bifurcations plots are generated and evinced to analyze and verify when this system is in the stability region or in a chaotic regimen. Then, a robust controller is designed to drive the system variables from the chaotic regimen to stability so that these variables reach the equilibrium point in finite time. The robust controller is obtained by selecting an appropriate robust control Lyapunov function to obtain the resulting control law. For synchronization purposes, the novel chaotic system designed in this study is used as a drive and response system, considering that the error variable is implemented in a robust control Lyapunov function to drive this error variable to zero in finite time. In the control law design for stabilization and synchronization purposes, an extra state is provided to ensure that the saturated input sector condition must be mathematically tractable. A numerical experiment and simulation results are evinced, along with the respective discussion and conclusion. 相似文献
10.