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941.
Regioorientation in the Addition Reaction of α‐Substituted Cinnamonitrile to Enamines Utilizing Chitosan as a Green Catalyst: Unambiguous Structural Characterization Using 2D‐HMBC NMR Spectroscopy
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Said A. S. Ghozlan Ahmed Gamal Ahmed Ismail Abdelshafy Abdelhamid 《Journal of heterocyclic chemistry》2016,53(3):817-823
Hexahydroquinolines and their fused derivatives are obtained in good to excellent yields by proceeding through a simple, mild, and efficient procedure including the reaction of enamines with substituted cinnamonitriles using DABCO, piperidine, or chitosan as catalysts. The regioorientation of Michael addition was established with no doubt using the 2D‐HMBC spectroscopy. 相似文献
942.
Adeleke Abdulrahman Oyekanmi Ab Aziz Abd Latiff Zawawi Daud Radin Maya Saphira Radin Mohamed Norli Ismail Adila Ab Aziz 《International journal of environmental analytical chemistry》2019,99(8):707-725
The adsorption of Cd and Pb ions from palm oil mill effluent on a mesoporous-activated cow bone composite powder has been investigated. Adsorbent was developed from cow bones, coconut shells and zeolite. The composite examined in the present work has a BET surface area of 248.398 m2/g. The optimisation of the removal efficiency of the heavy metals was investigated using central composite design and analysed using response surface methodology. The analysis of variance of the quadratic model signified that the model suitably predicted the uptake of the heavy metal ions at a 95% confidence level. The optimal operating condition was recorded at pH 4, 50 rpm, within 24 h and 1 mm of particle size and 12.5 gL?1 of adsorbent dosage. The characteristics of the composite were investigated using the Fourier transform irradiation. The morphology and chemical composition of composite was examined using the scanning electron microscopy equipped with energy dispersive x-ray. Characterisation study was conducted before and after the adsorption process. The results obtained illustrated that the removal of cadmium and lead from POME was influenced by the functional groups available on the surface of the composite. The carboxyl and hydroxyl groups are mainly responsible for the removal of cadmium and lead through chelating process. The point of zero charge (pHpzc) revealed that the adsorbent contained acidic sites with negatively charge surface which influenced the adsorption process. The experimental data of the heavy metals of Cd and Pb investigated were fitted to the Langmuir and Freundlich models. The result revealed that the adsorption equilibrium data fitted better to the Langmuir model for the adsorption Cd and to the Freundlich model for the adsorption of Pb. 相似文献
943.
We investigate the collinear ternary fission of the 260No isotope. The calculations are performed in the framework of the three cluster model for all possible accompanied light particles of even mass numbers A=4−52. The folding nuclear and Coulomb interaction potentials are used, based on the M3Y-Reid nucleon–nucleon force for the nuclear part. The deformation of the involved fragments and their relative orientations with respect to each other inside the fissioning nuclei are considered. Among all possible fragmentation channels, the suggested most probable channels are indicated as the ones showing a peak in the Q-value and a local minimum in the fragmentation potential, with respect to the mass and charge asymmetries. The indicated favored fragmentation channels from the approximate spherical calculations and those obtained after considering the deformations of the produced fragments are discussed in detail. In addition to the preferred heavy fragments of closed shells, favored prolate ones of high deformations appear when the nuclear deformations are taken into account. Among indicated fifty six favored channels, a collinear ternary fission of the 260No isotope is indicated to be most favored through the fragmentation channels of 15058Ce+410Be+40100Zr,60152Nd+412Be+3896Sr,58150Ce+614C+3896Sr,58148Ce+616C+3896Sr,54140Xe+822O+4098Zr,42106Mo+1848Ar+42106Mo and 41104Nb+2052Ca+41104Nb. 相似文献
944.
Gregory B. Kharas Lujain A. Alyahya Sara M. Rocus Aisha Ismail Rosio Juarez Alfreda Kavaliauskaite 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(12):725-728
Novel trisubstituted ethylenes, oxy ring-disubstituted propyl 2-cyano-3-phenyl-2-propenoates, RPhCH = C(CN)CO2C3H7 (where R is 4-methoxy-2-methyl, 4-methoxy-3-methyl, 3-ethoxy-4-methoxy, 3,4-dibenzyloxy, 3-benzyloxy-4-methoxy, 4-benzyloxy-3-methoxy) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and propyl cyanoacetate and characterized by CHN elemental analysis, IR, 1H- and 13C-NMR. All the ethylenes were copolymerized with styrene (M1) in solution with radical initiation (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C-NMR, GPC, DSC, and TGA. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (3–22% wt.), which then decomposed in the 500–800°C range. 相似文献
945.
Ismail Warad Mohammad Azam Saud I. Al-Resayes Mohammad Shahidul Islam Sarfaraz Ahmed Salim F. Haddad 《Research on Chemical Intermediates》2016,42(2):379-389
Two new palladium complexes derived from the di(2-pyridinyl)methanone N-(2-pyridinyl)hydrazone (DPMNPH) ligand are reported. The compounds were characterized by elemental analysis, spectroscopic studies, and, for the DPMNPH ligand, single-crystal X-ray diffraction analysis. The DPMNPH ligand crystallized as orthorhombic with the space group P212121. The H1 atom is intramolecularly bonded to the pyridinic N4 with N1–H1 = 0.92(3) Å, H1···N4 = 1.87(2) Å, N1···N4 = 2.615(2) Å, and N1–H1···N4 = 137(2)°. Both complexes were excellent catalysts in the Heck reaction in the presence of base. 相似文献
946.
Hydrazononitriles as Precursors for 4‐aminotriazoles and 3‐aminoisoxazoles: One Pot Synthesis of triazolo[1,5‐a]quinazoline Derivatives
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Ismail A. Abdelhamid Amr M. Abdelmoniem Said A. S. Ghozlan Holger Butenschön 《Journal of heterocyclic chemistry》2016,53(4):1251-1258
The reaction of various hydrazononitriles with hydroxylamine hydrochloride yielded various products, namely, 3‐aminoisoxazolone, 3‐amino‐1,2,4‐triazole and 4‐amino‐1,2,3‐triazole derivatives depending on the nature of substituents. 相似文献
947.
Fatma U. Afifi Violet Kasabri Simona C. Litescu Ismail M. Abaza 《Natural product research》2016,30(16):1777-1786
Arum dioscoridis and A. palaestinum (Araceae) are indigenous plant species in Jordan. HPLC-MS analysis of A. dioscoridis revealed the presence of apigenin, luteolin, quercetin, quercetin-3-O-β-glucoside, vitexin, isoorientin, esculin, and caffeic and ferulic acids. Both Arum spp., influenced gastrointestinal carbohydrate and lipid digestion and absorption. Orlistat inhibited dose dependently and highly substantially pancreatic lipase (PL) in vitro. Similar to orlistat, Arum species aqueous extracts (AEs), apigenin, caffeic acid and esculin exhibited a concentration related PL inhibition. Comparable to acarbose, dual inhibition of α-amylase/α-glucosidase was observed for both Arum species. Like guar gum, A. dioscoridis AE minimised substantially area under 24 h glucose curve. Acute starch-induced postprandial hyperglycaemia in overnight fasting rats was highly significantly (p?<?0.001) decreased by A. dioscoridis AE. A. palaestinum could not perform effectively in either starch- or glucose-fed fasting rats. No antiproliferative effects against colorectal cancer cell lines HT29, HCT116 and SW620 were detected for tested Arum spp. 相似文献
948.
In this paper, we solve dual and triple sequences involving q-orthogonal polynomials. We also introduce and solve a system of dual series equations when the kernel is the q-Laguerre polynomials. Examples are included. 相似文献
949.
This article deals with a quasilinear elliptic equation with variable exponent under a homogenous Dirichlet boundary-value condition, where nonlinearity also depends on the gradient of the solution. By using an iterative method based on Mountain Pass techniques, the existence of a positive solution is obtained. 相似文献
950.
A sensitive and selective spectrofluorimetric method has been developed for the rapid determination of europium(III). This method is based on the formation of nonluminous complex between Eu(III) and a Schiff base reagent N, N′-bis (salicylidene)-1,2-phenylenediamine (PABD) and measuring the fluorescence quenching of Eu(III)-PABD complex at λex/em = 390/577 nm. The fluorescence intensity complex decreased linearly by increasing the Eu(III) concentration in the range of 1.0–13.0 μM. The optimum conditions for the complex formation were determined such as a pH .0 of borate buffer. The limits of detection (LOD) and quantification (LOQ) of Eu(III) were determined and found to be 0.217 and 0.653 μM, respectively. The maximum relative standard deviation of the method for an europium(III) standard of 6.0 μM was 2.07 % (n = 6). The proposed procedures could be applied successfully for the determination of the investigated metal ion in some spiked water samples with a good precision and accuracy compared to official and reported methods as revealed by t- and F-tests. 相似文献