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31.
Action of Hydrazines on 2‐(2‐Oxindolin‐3‐ylidene)malononitrile, (E,Z)‐Ethyl 2‐cyano‐2‐(2‐oxindolin‐3‐ylidene)acetate and Isatin‐β‐thiosemicarbazone as a Source of Spiro Indoline‐pyrazole Systems 下载免费PDF全文
Ahmed S. A. Youssef Magdy M. Hemdan Samir A. Emara Rabaa M. Kamel 《Journal of heterocyclic chemistry》2015,52(5):1331-1336
2‐(2‐Oxindolin‐3‐ylidene)malononitrile ( 1a ) or (E,Z)‐ethyl 2‐cyano‐2‐(2‐oxindolin‐3‐ylidene)acetate ( 1b ) or isatin‐β‐thiosemicarbazone ( 1c ) undergoes reactions with prototype hydrazine hydrate itself and some of its simple congeners to give hydrazone derivatives bearing indoline‐2‐one moiety ( 2 ). The hydrazone derivatives ( 2 ) when heated with acetyl acetone or ethyl acetoacetate in dry pyridine afforded the spiro indoline derivatives ( 3a , 3b ). Also, cinnoline derivative ( 9 ) is obtained by action of hydrazine hydrate on the N‐acetyl derivative of ( 6a ). The structures of the newly synthesized compounds were evaluated by IR, 1H‐NMR spectroscopy, mass spectra and elemental analyses. 相似文献
32.
el-Nahass MM Kamel MA el-Deeb AF Atta AA Huthaily SY 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(3):443-450
The optimized geometry and vibrational frequencies of P-N,N-dimethylaminobenzylidenemalononitrile (DBM) were obtained by ab initio HF and DFT/B3LYP levels with complete relaxation in the potential energy surface using 6-31++G(d,p) and 6-311++G(d,p) basis sets. The Fourier-transform infrared (FT-IR) spectrum of DBM has been recorded in the region 4000-400 cm(-1). The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR spectrum. The calculated frequencies are in good agreement with the experimental frequencies. 相似文献
33.
Bouderdara N Elomri A Djarri L Medjroubi K Seguin E Vérité P 《Natural product communications》2011,6(1):115-117
The essential oil of aerial parts of Cachrys libanotis L. (Apiaceae) from east Algeria was extracted by hydrodistillation and analyzed by GC-FID and GC-MS. Thirty-one compounds were identified, the main components being germacrene-D (18.0%), gamma-terpinene (6.4%), p-cymene (5.5%), caryophyllene oxide (5.1%), and limonene (5.1%). 相似文献
34.
Hosni K Msaâda K Ben Taârit M Chahed T Marzouk B 《Natural product communications》2011,6(11):1731-1734
The chemical composition of the essential oils obtained by hydrodistillation from the aerial parts of the Tunisian Hypericum perforatum and H. ericoides ssp. roberti was elucidated by a combination of GC and GC-MS analyses. The main constituents of the oil of H. perforatum were alpha-pinene (11.8%), alpha-ylangene (10.4%), germacrene-D (9.5%), n-octane (6.5%) and alpha-selinene (5.9%). The oil of H. ericoides ssp. roberti exhibited a higher amount of aliphatic and branched hydrocarbons and the main constituents were n-octane (29.1%), alpha-pinene (10.9%), pulegone (7.7%) and acetophenone (7%). Both qualitative and quantitative differences were observed between the studied oils. This chemical variability seems likely to result from the genetic variability, since samples of both species were collected at the same location and processed under the same conditions. 相似文献
35.
ABSTRACTHydrogen storage reactions on Ni ? C59X(X = B, N) heterofullerene are investigated by using the state-of-the-art density functional theory calculations. The Ni atom prefers to bind at the bridge site between two hexagonal rings, and can bind up to five hydrogen molecules with average adsorption energies of (?0.94, ?0.48, ?0.33, ?0.25 and ?0.20 eV) per hydrogen molecule for Ni ? C59B, while (?1.20, ?0.60, ?0.41, ?0.28 and ?0.23 eV) per hydrogen molecule for Ni ? C59N. With no metal clustering, the system gravimetric capacities are expected to be as large as 10.87 and 10.85 wt % for 5H2NiC59B?and 5H2NiC59N, respectively. While the desorption activation barriers of the complexes 1H2 + C59X?(X = B, N)?are outside the Department of Energy domain (?0.2 to ?0.6 eV), the desorption activation barriers of the complexes nH2 + C59X(X = B, N)(n = 2 ? 5) are inside this domain. The hydrogen storage of the irreversible 1H2 + NiC59X?(X = B, N) and reversible 2H2 + NiC59X?(X = B, N) interactions is characterised in terms of density of states and projected densities of states, pairwise and non-pairwise additivity, infrared, Raman, electrophilicity and molecular electrostatic potentials. 相似文献
36.
The action of nitrous acid on 2-amino-6-nitro-N-methylaniline affords 1-methyl-7-nitro-benzotriazole. The corresponding 7-amino-, acetylamino-, and benzoylamino-derivatives have been prepared. Thus the compounds and their derivatives previously assigned the 1-methyl-7-nitro structure are the 4-substituted compounds. 相似文献
37.
We consider a multiple access MAC fading channel with two users communicating with a common destination, where each user mutually acts as a relay for the other one as well as wishes to transmit its own information as opposed to having dedicated relays. We wish to evaluate the usefulness of relaying from the point of view of the system’s throughput (sum rate) rather than from the sole point of view of the user benefiting from the cooperation as is typically done. We do this by allowing a trade-off between relaying and fresh data transmission through a resource allocation framework. Specifically, We propose a cooperative transmission scheme allowing each user to allocate a certain amount of power for its own transmitted data while the rest is devoted to relaying. The underlying protocol is based on a modification of the so-called non-orthogonal amplify-and-forward (NAF) protocol Azarian et al. [18]. We develop capacity expressions for our scheme and derive the rate-optimum power allocation, in closed form for centralized and distributed frameworks. In the distributed scenario, partially statistical and partially instantaneous channel information is exploited.The centralized power allocation algorithm indicates that even in a mutual cooperation setting like ours, on any given realization of the channel, cooperation is never truly mutual, i.e. one of the users will always allocate zero power to relaying the data of the other one, and thus act selfishly. But in a distributed framework, our results indicate that the sum rate is maximized when both mobiles act selfishly. 相似文献
38.
Uniqueness and existence of solutions for a singular system with nonlocal operator via perturbation method 下载免费PDF全文
Kamel Saoudi Mouna Kratou Eadah AlZahrani 《Journal of Applied Analysis & Computation》2020,10(4):1311-1325
In this work, we investigate the existence and the uniqueness of solutions for the nonlocal elliptic system involving a singular nonlinearity as follows:
$$
\left\{\begin{array}{ll}
(-\Delta_p)^su = a(x)|u|^{q-2}u +\frac{1-\alpha}{2-\alpha-\beta} c(x)|u|^{-\alpha}|v|^{1-\beta}, \quad
\text{in }\Omega,\ (-\Delta_p)^s v= b(x)|v|^{q-2}v +\frac{1-\beta}{2-\alpha-\beta} c(x)|u|^{1-\alpha}|v|^{-\beta}, \quad
\text{in }\Omega,\ u=v
= 0 ,\;\;\mbox{ in }\,\mathbb{R}^N\setminus\Omega,
\end{array}
\right.
$$
where $\Omega $ is a bounded domain in $\mathbb{R}^{n}$ with smooth boundary, $0<\alpha <1,$ $0<\beta <1,$ $2-\alpha -\beta
相似文献
39.
40.
The objectives of this paper are twofold. Firstly, we formulate a system of partial differential equations that models the contamination of groundwater due to migration of dissolved contaminants through unsaturated to saturated zone. A closed form solution using the singular perturbation techniques for the flow and solute transport equations in the unsaturated zone is obtained. Indeed, the solution can be used as a tool to verify the accuracy of numerical models of water flow and solute transport. The second part of this paper, deals with how the water level in a water reserve drops due to pumping water out of a well that is some distance away. 相似文献