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101.
102.
Mohamed I. Hegab Nasser A. Hassan Emad M. El‐Telbani Ibrahim S. Ahmed Farag Farouk M. E. Abdel‐Megeid 《Heteroatom Chemistry》2003,14(3):223-228
Hydrazones 12a–c and ketazines 13a–c were prepared by the reaction of ketones 11a–c with hydrazine hydrate depending on the temperature and the reaction time. Some ketone (aryl)hydrazone derivatives 14a,c,e reacted with thionyl chloride to afford the chlorothiadiazoline derivatives 15a–c . Surprisingly, the chlorine atom in the latter compounds was found to undergo smooth nucleophilic substitution, and by boiling these compounds in absolute ethanol gave the corresponding ethoxythiadiazoline derivatives 16a–c . The structure of the ethoxythiadiazoline 16b was confirmed by single crystal X‐ray determination. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:223–228, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10125 相似文献
103.
104.
Nasser R. El-Brollosy Claus Nielsen Erik B. Pedersen 《Monatshefte für Chemie / Chemical Monthly》2005,12(2):1247-1254
A series of Emivirine and GCA-186 analogues substituted at N-1 with indan-1-yloxymethyl (6a–6c) and indan-2-yloxymethyl (6d–6f) were synthesized by reaction of the corresponding bis(indanyloxy)methans with uracils having 5-ethyl or 5-isopropyl and 6-benzyl or 6-(3,5-dimethylbenzyl) substituents. A route to the corresponding N-1 substituted 4-hydroxybut-2-enyloxymethyl analogue was also devised. All newly synthesized compounds showed potent activity against wild-type HIV-1, the most active compound being 5-ethyl-1-(indan-1-yloxymethyl)-6-(3,5-dimethylbenzyl)uracil (6b), which was 50-fold more active than Emivirine. 相似文献
105.
Distributed point source method (DPSM) is gradually gaining popularity in the field of non-destructive evaluation (NDE). DPSM is a semi-analytical technique that can be used to calculate the ultrasonic fields produced by transducers of finite dimension placed in homogeneous or non-homogeneous media. This technique has been already used to model ultrasonic fields in homogeneous and multi-layered fluid structures. In this paper the method is extended to model the ultrasonic fields generated in both fluid and solid media near a fluid-solid interface when the transducer is placed in the fluid half-space near the interface. Most results in this paper are generated by the newly developed DPSM technique that requires matrix inversion. This technique is identified as the matrix inversion based DPSM technique. Some of these results are compared with the results produced by the Rayleigh-Sommerfield integral based DPSM technique. Theory behind both matrix inversion based and Rayleigh-Sommerfield integral based DPSM techniques is presented in this paper. The matrix inversion based DPSM technique is found to be very efficient for computing the ultrasonic field in non-homogeneous materials. One objective of this study is to model ultrasonic fields in both solids and fluids generated by the leaky Rayleigh wave when finite size transducers are inclined at Rayleigh critical angles. This phenomenon has been correctly modelled by the technique. It should be mentioned here that techniques based on paraxial assumptions fail to model the critical reflection phenomenon. Other advantages of the DPSM technique compared to the currently available techniques for transducer radiation modelling are discussed in the paper under Introduction. 相似文献
106.
Yahia Nasser Mabkhot Nahed Ahmed Kaal Seham Alterary Mohammad S. Mubarak Abdulrhman Alsayari Abdullatif Bin Muhsinah 《Journal of heterocyclic chemistry》2019,56(10):2845-2953
Phenacylbromide derivatives constitute a multilateral group of precursors for the synthesis of numerous heterocycles of organic compounds. Briefly, 5‐(2‐bromo‐acetyl)‐substituted‐thiophene derivative has been used as a synthon for synthesis of new thiophene‐containing compounds through the reaction with nucleophilic nitrogen compounds and thioamides. The suggested structures of the newly synthesized thiophene compounds were confirmed and assured with different spectroscopic tools and with CHN elemental analysis. Additionally, the antimicrobial activity of these thiophene compounds was recorded to investigate their potency against various types of bacteria and fungi. Results showed that these compounds exhibit significant inhibitory activity against the growth of tested bacterial and fungal strains and that some derivatives were more potent than the employed reference drugs. 相似文献
107.
Nasser Metwally 《International Journal of Theoretical Physics》2008,47(3):623-633
A model of two 2-level atoms interacts with a single quantized electromagnetic field is considered. We study the effect of
the mean photon number and the structure of the initial states of the two atoms on the dynamics of the atomic system from
the separability point of view. It is found that, if we start from a product mixed atomic state, the probability of generating
long living entangled states is increased as the mean photon number increases. Starting from excited atomic system in product
state, one generates a more stable entangled states with high degree of entanglement. Also, the effect of the mean photon
number on atomic system prepared initially in entangled states is investigated. It is found that the entangled state generated
from the initially partial entangled states are more robust than those obtained from a maximum entangled state. The Pancharatnam
phase for the separable and entangled states is studied under the effect of the mean photon number and the structure of the
initial state. We find that for the separable states, the collapses decrease and the amplitude of the revivals is smaller
than that for the entangled state, so there are long-living entangled phases. This property give us a great chances to store
safely information in entangled state. 相似文献
108.
Mabkhot YN Al-Majid AM Alamary AS Warad I Sedigi Y 《Molecules (Basel, Switzerland)》2011,16(6):5142-5148
Facile and convenient syntheses of bisdimethylthieno[2,3-b]thiophen-2,5-diyl bis(oxazole-2-amine), bis(1H-imidazol-2-amine), bis((3a)-H-indole),[1,2-a]pyrimidine), bis(1H-imidazo[1,2-b][1,2,4]triazole) and bis(9H-benzo[d]imidazo[1,2-a]imidazole) derivatives incorporating a thieno[2,3-b]thiophene moiety from the versatile and readily accessible 1,1'(3,4-dimethylthieno[2,3-b]thiophene-2,5-diyl)-bis(2-bromo-ethanone) (1) are described. 相似文献
109.
110.
Nasser–eddine Tatar 《Mediterranean Journal of Mathematics》2013,10(1):213-226
A new assumption on the relaxation in a viscoelastic problem ensuring uniform stability in an arbitrary rate is established. This assumption replaces a usual condition and allows for a much wider class of kernels. As consequences several earlier results are extended and improved. 相似文献