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61.
M. A. Aboutabl M. A. Abdel Aziz A. A. Magd El Din H. A. Elwy H. M. Fahmy 《Monatshefte für Chemie / Chemical Monthly》1991,122(10):765-770
Summary The polarographic behaviour of the title compounds is reported and discussed in acid media. The obtained data indicate that these compounds undergo a four-electron reduction. A mechanism for the electrode process atpH<7 is proposed, discussed and clarified via identification of controlled potential electrolysis (CPE) product and application of cyclic voltammetry (CV).
Die elektrochemische Reduktion einiger 3-Aryl-2-cyanothioacrylamid-Derivate an der DME
Zusammenfassung Es wurde das polarographische Verhalten der Titelverbindungen in saurem Medium untersucht. Die erhaltenen Daten zeigen, daß diese Verbindungen eine Vierelektronenreduktion eingehen. Es wird ein Mechanismus für den Elektrodenprozess beipH<7 vorgeschlagen und diskutiert. Zur Klärung der Verhältnisse wurden die mittels kontrollierter Potential-Elektrolyse (CPE) erhaltenen Produkte identifiziert und auch cyclische Voltammetrie eingesetzt.相似文献
62.
Nourhan Samy Elmalahany Muhammed Abdel-Hamied Abdel-Tawab Hanan M. Elwy Hussein M. Fahmy Rasha M. El Nashar 《Electroanalysis》2023,35(5):e202200313
Saxagliptin (Saxa) belongs to a new generation of antidiabetic pharmaceutical compounds used in combination with healthy diet and exercise to lower blood glucose levels in patients with type 2 diabetes mellitus (T2DM). In this work, we report for the first time a molecularly imprinted polymer (MIP) based electrochemical sensor for the determination of Saxa. Computational calculations were performed, based on which five MIPs were synthesized using Saxa as a template, itaconic acid as a monomer, crosslinked with ethylene glycol dimethacrylate and Di methyl sulfoxide (DMSO) as a porogen with different ratios. Non-covalent interaction (NCI) analysis has been also conducted, and the obtained isosurface analysis was used for graphical visualization of NCI that could occur in real space as well as for the discrimination between hydrogen bond interaction, Van Der Waals attraction and spatial repulsion. The optimized polymer was incorporated as a modifier for designing an electrochemical sensor comprising MIP and Multiwalled carbon nanotubes (MwCNT) within carbon paste electrode (CPE). The operational variables including incubation time, pH, scan rate, and accumulation time were optimized. The sensor showed linearity over the concentration range (1 × 10−9–1 × 10−15 M) with low limit of detection (LOD) 8 × 10−16 and 2 × 10−16 M on using DPV and EIS, respectively. The sensor was successfully applied for pharmaceutical formulations, urine, and human serum samples with recovery range between 97.45–100.64 %. 相似文献
63.
Mohamed SA El-Badry MO Drees EA Fahmy AS 《Applied biochemistry and biotechnology》2008,150(2):127-137
The major pool of peroxidase activity is present in the peel of some Egyptian citrus species and cultivars compared to the juice and pulp. Citrus jambhiri cv. Adalia had the highest peroxidase activity among the examined species. Four anionic and one cationic peroxidase isoenzymes from C. jambhiri were detected using the purification procedure including ammonium sulfate precipitation, chromatography on diethylaminoethanol-cellulose, carboxymethyl-cellulose, and Sephacryl S-200 columns. Cationic peroxidase POII is proved to be pure, and its molecular weight was 56 kDa. A study of substrate specificity identified the physiological role of POII, which catalyzed the oxidation of some phenolic substrates in the order of o-phenylenediamine > guaiacol > o-dianisidine > pyrogallol > catechol. The kinetic parameters (K (m), V (max), and V (max)/K (m)) of POII for hydrolysis toward H2O2 and electron donor substrates were studied. The enzyme had pH and temperature optima at 5.5 and 40 degrees C, respectively. POII was stable at 10-40 degrees C and unstable above 50 degrees C. The thermal inactivation profile of POII is biphasic and characterized by a rapid decline in activity on exposure to heat. The most of POII activity (70-80%) was lost at 50, 60, and 70 degrees C after 15, 10, and 5 min of incubation, respectively. Most of the examined metal ions had a very slight effect on POII except of Li+, Zn2+, and Hg2+, which had partial inhibitory effects. In the present study, the instability of peroxidase above 50 degrees C makes the high temperature short time treatment very efficient for the inactivation of peel peroxidase contaminated in orange juice to avoid the formation of off-flavors. 相似文献
64.
Wafaa M. Abdou Neven A. Ganoub Amin F. Fahmy Abeer A. Shaddy 《Monatshefte für Chemie / Chemical Monthly》2006,137(1):105-116
Summary. Two simple and efficient one-pot procedures for the synthesis of a series of α-branched N-heterocycle-substituted methane-1,1-bisphosphonates
are outlined. In the first method, the parent halosubstrates were reacted with cyanomethylphosphonate followed by reaction
with dialkyl phosphonates to give asymmetrical or symmetrical bisphosphonates (BPs). In the second approach, the same halocompounds were reacted with tetraethyl methyl-1,1-bisphosphonate to give the requisite
BPs. Partial and complete hydrolysis of the prepared BPs were also investigated. The products contain functional groups advantageous for further synthetic modification as structural
units for coupling with the drug. 相似文献
65.
Jan Becher Fahmy M. Asaad Tea Johansen Jesper Hansen Sine Larsen Flemming Hansen 《Journal of heterocyclic chemistry》1986,23(2):567-575
Aldol condensation of 3-formyl-2(1H)-pyridinethiones and the corresponding pyridones with ketones such as acetophenones in aqueous base yields 3-hydroxy-1-propanones in high yields. Reaction with propiophenone showed this reaction to be highly diastereoselective as only the erythro-isomer is formed at room temperature. This assignment was based on an X-ray crystallographic investigation of the compound given in the title. Aldol condensations of a number of related 3-acetyl-2(1H)-pyridinethiones with benzaldehyde yielded the corresponding trans-vinyl ketones. 相似文献
66.
Raimund Marx Nikolas Pomplun Wolfgang Bermel Heinz Zeiger Frank Engelke Amr F. Fahmy Steffen J. Glaser 《Magnetic resonance in chemistry : MRC》2015,53(6):442-447
The realization of an all‐heteronuclear 5‐qubit nuclear magnetic resonance quantum computer is reported, from the design and synthesis of a suitable molecule through the engineering of a prototype 6‐channel probe head. Full control over the quantum computer is shown by a benchmark experiment. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
67.
It is shown how one can transform scalar first-order ordinarydifferential equations which admit non-local symmetries of theexponential type to integrable equations admitting canonicalexponential non-local symmetries. As examples we invoke theAbel equation of the second kind, the Riccati equation and naturalgeneralizations of these. Moreover, our method describes howa double reduction of order for a second-order ordinary differentialequation which admits a two-dimensional Lie algebra of generatorsof point symmetries can be affected if the second-order equationis first reduced in order once by a symmetry which does notspan an ideal of the two-dimensional Lie algebra. 相似文献
68.
Leila S. Boulos Ewies F. Ewies Amin F. M. Fahmy 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):726-738
Abstract The reaction of 1,2-bis(diphenylphosphino)ethane with substituted o-benzo-quinones afforded new bis(6-hydroxycyclohexa-2,4-dienone) derivatives. Treatment of the same reagent with o-naphthoquinone, phenanthrenequinone, and acenaphthenequinone gave the respective bis(diphenylphosphoryl)ethylidenes or diacenaphthylenone derivatives. On the other hand, p-quinones react with 1,2-bis(diphenylphosphino)methane to yield the corresponding 4-hydroxycyclohexa-2,5-dien-1-ones. Possible reaction mechanisms are considered and the structural assignments are based on compatible analytical and spectroscopic data. 相似文献
69.
M. M. Aly A. M. Fahmy A. M. Gaber 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):253-258
Abstract Thermolysis of N-benzoyl-N′-phenylthiourea (BPTU) on heating in air at 230°C gives NH3, H2S, benzaldehyde, benzil, aniline, azobenzene, benzamide, benzanilide, phenylisothiocyanate, phenyl-cyanamide, thiocarbanilide and benzoylisothiocyanate, whereas thermolysis of N-benzoy1-N′-benzylthiourea (BBTU) affords NH3, H2S, benzaldehyde, benzil, toluene, bibenzyl, stilbene, benzamide, cyanamide, benzylisothiocyanate, benzoylthiourea and benzoylisothiocyanate. Thermolysis of N-benzoyl-N′-α-naphthylthiourea (BNTU) under the same conditions gives NH3, H2S. benzaldehyde, benzil, benzamide, α-naphthylisothiocyanate, α-naphthanilide, α-naphthylcyanamide. benzoylisothiocyanate, α-naphthylamine and N,N′-di-α,α′-naphthylthiourea. Analogous results were also obtained on photolysis of (BFTU), (BBTU) and (BNTU) with the exception of NH3, and the photodegradation products of phenylthiourea, benzylthiourea and a-naphthylthiourea respectively. The main feature of these pyrolyses is the homolysis of the amide and thioamide bonds providing free radicals that undergo different reactions involving H-abstraction, dimerization, coupling, fragmentation, rearrangement and disproportionation to yield the identified products. 相似文献
70.
Olav Vahtras Hans rgren Hans Jrgen AA. Jensen 《Journal of computational chemistry》1994,15(6):573-579
The evaluation of gradient vectors of a general operator with one-index, double-one-index, or higher-order one-index transformed integrals is a key operation in multiconfiguration response theory calculations. We describe an integral-driven direct algorithm that carries out this operation efficiently without pretransforming the integrals. The use of this algorithm leads to a considerable reduction in disk space and timing. © 1994 by John Wiley & Sons, Inc. 相似文献