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961.
Mohamed Ali Aboutabl Hussein Mahmoud Fahmy Hassan Abdel Rahman 《Monatshefte für Chemie / Chemical Monthly》1990,121(12):991-998
Summary The polarographic reduction of two series of pyrazolone derivatives in alcoholic buffered media indicated that these molecules predominate in the hydrazone form and are reduced via a 4e– irreversible process. The main eletrolysis products, 3,6-bis(pyrazoline-5-on-3yl)piperazine-2,5-dione (3), and 3,6-bis(1-phenyl-pyrazoline-5-on-3yl)piperazine-2,5-dione (4) were isolated and identified. A mechanism has been suggested and discussed.
Die Elektroreduktion von Pyrazolon-Glyoxalester-Derivaten in wäßrigem, gepuffertem Medium
Zusammenfassung Die polarographische Reduktion zweier Serien von Pyrazolon-Derivaten in alkoholisch-wäßrigem, gepuffertem Medium zeigt, daß diese Moleküle bevorzugt in der Hydrazono-Form vorliegen und über einen irreversiblen 4e–-Prozeß reduziert werden. Die Hauptprodukte der Elektrolyse, 3,6-bis(pyrazolin-5-on-3-yl)piperazin-2,5-dion (3) und 3,6-bis(phenylpyrazolin-5-on-3-yl)piperazin-2,5-dion (4) wurden isoliert und identifiziert. Ein Mechanismus wird vorgeschlagen und diskutiert.相似文献
962.
Shawkat A. Abdel‐Mohsen 《中国化学会会志》2003,50(5):1085-1092
5‐(2‐Aminothiazol‐4‐yl)‐8‐hydroxyquinoline 2 has been synthesized by treating thiourea with 5‐chloroacetyl‐8‐hydroxyquinoline 1 . The amine 2 was treated with aromatic aldehydes to furnish schiff bases 6a‐c which on treatment with phenyl isothiocyanate gave the corresponding thiazolo‐s‐triazines 7a‐c . Reaction of 2 with phenyl isothiocyanate gave the corresponding aminocarbothiamide derivative 8 which on reaction with malonic acid in acetyl chloride afforded thiobarbituric acid derivative 9 . Coupling of 9 with diazonium salt gave the phenyl hydrazono derivative 10 . However, reaction of 2 with carbon disulphide and methyl iodide afforded dithiocarbamidate 12 which on treatment with ethylenediamine, o‐aminophenol and/or phenylenediamine gave the aminoazolo derivatives 13–15 , respectively. Other substituted fused thiazolopyrimidines 16–20 have been also prepared by the reaction of 2 with some selected dicarbonyl reagents. The characterisation of synthesized compounds has been done on the basis of elemental analysis, IR, 1H‐NMR and mass spectral data. All the newly synthesized compounds have been screened for their antimicrobial activities. 相似文献
963.
Abdel‐Rahman H. Abdel‐Rahman Margret M. Girges Abdel‐Aziz S. El‐Ahl Lamyaa M. Sallam 《Heteroatom Chemistry》2006,17(1):2-7
A number of new benzo[h]‐ and benzo[f]chromeno[2,3‐b] pyridine‐5‐ones derivatives were synthesized from benzo[h]‐ and benzo[f]‐chromone‐carbonitriles and amino‐benzo[h]‐ and benzo[f]chromone‐carbaldehydes. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:2–7, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20152 相似文献
964.
This paper deals with stochastic scheduling of nuclear power plant outages. Focusing on the main constraints of the problem, we propose a stochastic formulation with a discrete distribution for random variables, that leads to a mixed 0/1 quadratically constrained quadratic program. Then we investigate semidefinite relaxations for solving this hard problem. Numerical results on several instances of the problem show the efficiency of this approach, i.e., the gap between the optimal solution and the continuous relaxation is on average equal to 53.35 % whereas the semidefinite relaxation yields an average gap of 2.76 %. A feasible solution is then obtained with a randomized rounding procedure. 相似文献
965.
Shaaban K. Mohamed Sabry H. H. Younes Eman M. M. Abdel‐Raheem Joel T. Mague Mehmet Akkurt Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(11):959-964
The wide diversity of applications of thiosemicarbazones and bis(thiosemicarbazones) has seen them used as anticancer and antitubercular agents, and as ligands in metal complexes designed to act as site‐specific radiopharmaceuticals. Molecules of 1,1′‐({[(ethane‐1,2‐diyl)dioxy](1,2‐phenylene)}bis(methanylylidene))bis(thiosemicarbazide) {alternative name: 2,2′‐[ethane‐1,2‐diylbis(oxy)]dibenzaldehyde bis(thiosemicarbazide)}, C18H20N6O2S2, (I), lie across twofold rotation axes in the space group C2/c, with an O—C—C—O torsion angle of −59.62 (13)° and a trans‐planar arrangement of the thiosemicarbazide fragments relative to the adjacent aryl rings. The molecules of (I) are linked by N—H...S hydrogen bonds to form sheets containing R24(38) rings and two types of R22(8) ring. In the N,N‐dimethylformamide disolvate, C18H20N6O2S2·2C3H7NO, (II), the independent molecular components all lie in general positions, but one of the solvent molecules is disordered over two sets of atomic sites having occupancies of 0.839 (3) and 0.161 (3). The O—C—C—O torsion angle in the ArOCH2CH2OAr component is −75.91 (14)° and the independent thiosemicarbazide fragments both adopt a cis‐planar arrangement relative to the adjacent aryl rings. The ArOCH2CH2OAr components in (II) are linked by N—H...S hydrogen bonds to form deeply puckered sheets containing R22(8), R24(8) and two types of R22(38) rings, and which contain cavities which accommodate all of the solvent molecules in the interior of the sheets. Comparisons are made with some related compounds. 相似文献
966.
Maisa I. Abdel Moneam 《Monatshefte für Chemie / Chemical Monthly》2004,4(6):45-53
The reaction of 3-chloro-5,6-diphenylpyridazine-4-carbonitrile with potassium thiocyanate gave the corresponding isothiocyanate derivative. This was reacted with aromatic amines in ethanol to afford pyrimido[4,5-c]pyridazine derivatives. The reaction of the latter compounds with hydrazine hydrate led to the formation of 6-hydrazino derivatives. One hydrazino compound was reacted with a variety of reagents to produce other new pyrimidopyridazines as well as a number of s-triazolo derivatives. 相似文献
967.
Electrochemical Morphine Sensor Based on Gold Nanoparticles Metalphthalocyanine Modified Carbon Paste Electrode 下载免费PDF全文
Composites of gold nanoparticles (Au) electrochemically deposited and different metal phthalocyanines (Co, Ni, Cu, and Fe) were chemically prepared. The composites were used as modifiers for carbon paste electrodes and were used for the determination of morphine in presence of ascorbic acid and uric acid. Central metal atoms of phthalocyanine moiety affected the rate of electron transfer. Thus, the electroactivity of different modifiers were evaluated towards morphine oxidation. Au‐CoPcM‐CPE possessed the highest rate for charge transfer rate in all studied pH electrolytes. Limit of detection was 5.48×10?9 mol L?1 in the range of 4.0×10?7 to 9.0×10?4 mol L?1. 相似文献
968.
969.
在细小MgO增强颗粒的存在下,采用电沉积法在碳阳极上经瓦特镍制得Ni–MgO纳米复合物,考察了它在碱性介质中电催化氧化甲醇和乙醇反应性能,并与碳涂覆的纯Ni催化剂(Ni/C)性能进行了比较。运用能量散射谱、X射线衍射和扫描电镜分别表征了沉积的纳米复合物的化学组成、相结构和表面形貌,并采用循环伏安法(CV)、计时电流法和电化学阻抗谱(EIS)等电化学技术考察了所制电催化剂阳极的催化活性。结果表明, Ni/C催化剂在电氧化反应中表现出很低的催化活性和稳定性,而MgO的引入显著增加了Ni催化剂在醇氧化反应中的催化活性和抗中毒性能。 EIS和CV结果证实Ni–MgO/C纳米复合物电极具有比Ni/C更低的电荷转移阻力和更高的抗中毒性能。 相似文献
970.
The reactions of K3[Cu(CN)4], 3-acetylpyridine (3-Acpy) or 4-acetylpyridine (4-Acpy) in the presence of Me3SnCl in H2O/acetonitrile media at room temperature afford the 3D-supramolecular coordination polymers (SCPs)∞3[Cu2CN(μ-CN)·(3-Acpy)2] 1 and ∞3[Cu2CN(μ-CN)·(4-Acpy)2] 2. The structures of 1 and 2 consist of Cu2CN building blocks which are connected by CN groups, forming 1D-zig-zag chains. Each chain is bonded to another chain by hydrogen bonding into a 2D-layer, which is further stacked in an interwoven mode by π–π stacking interactions and hydrogen bonds in 1 and 2, as well as Cu···Cu interactions in 1, to create supramolecular 3D-network structures. The high dimensional topologies of 1 and 2 result mainly from extensive hydrogen bonding and π–π stacking. The long wavelength absorption band at 400–420 nm in the electronic spectra of 1 and 2 is assigned to a CT from copper(I) to the Acpy ligand. Compound 2 exhibits strong luminescence at 485 and 527 nm, corresponding to MLCT and metal-centered transitions, respectively. 相似文献