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151.
Aly Ashraf A. Hassan Alaa A. Mohamed Nasr K. El-Shaieb Kamal M. Makhlouf Maysa M. Bräse Stefan Nieger Martin 《Research on Chemical Intermediates》2019,45(2):613-631
Research on Chemical Intermediates - The reaction of N-substituted hydrazinecarbothioamides with both 2-(bis(methylthio)methylene)malononitrile and ethyl 2-cyano-3,3-bis(methylthio)acrylate... 相似文献
152.
M. Shaheer Malik Zaki S. Seddigi Shaik Bajee Shaik Azeeza Syed Riyaz Saleh A. Ahmed Ismail I. Althagafi Qazi M. Sajid Jamal Ahmed Kamal 《Journal of Saudi Chemical Society》2019,23(4):503-513
The versatility of multicomponent Biginelli’s reaction is exploited in the development of proline and cyclized cysteine tethered conjugates of monastrol, a kinesin Eg5 inhibitor. Ten new conjugates are synthesized focusing on structural replacement of the ester moiety (C-5 position) of the monastrol backbone with amino acid based amide moieties. On cytotoxic evaluation, conjugate 24 has shown promising in vitro cytotoxic activity against leukemia. Molecular docking studies revealed that the conjugates 19 and 24 exhibit better interaction at kinesin Eg5 receptor compared to monastrol. Moreover, computational calculations and predictions of important molecular properties suggest that these new amino acid based conjugates could be further improved to provide potential anticancer agents. 相似文献
153.
Subdiffraction resolution in total internal reflection fluorescence microscopy with a grating substrate 总被引:1,自引:0,他引:1
We propose a fluorescence surface imaging system that presents a power of resolution beyond that of the diffraction limit without resorting to saturation effects or probe scanning. This is achieved by depositing the sample on an optimized periodically nanostructured substrate in a standard total internal reflection fluorescence microscope. The grating generates a high-spatial-frequency light grid that can be moved throughout the sample by changing the incident angle. An appropriate reconstruction procedure permits one to recover the fluorescence amplitude from the images obtained for various incidences. Simulations of this imaging system show that the resolution is not limited by diffraction but by the period of the grating. 相似文献
154.
Mohd Jailani Mohd Nor Mohammad Hosseini Fouladi Ahmad Kamal Ariffin 《Applied Acoustics》2008,69(4):343-353
Sound quality is among the main factors that influence customers’ preference for choosing good automobile products. It all started more than 10 years ago and grows up so fast due to high competition in the automotive industries. A-weighted noise levels and sound power are usually utilised to measure the noise but they are not adequate to characterise the impact sound inside a car. The most popular approach to determine sound quality of a product is to define an annoyance or specific index, which involves both subjective and objective evaluations. Subjective and objective tests should be studied concurrently in order to determine the sound quality inside a passenger car. This approach is used in this paper to evaluate vehicle comfort index according to most frequently used sound quality metrics, namely; Zwicker loudness, sharpness, roughness and fluctuation strength. As a result researchers of different fields of automotive acoustics investigations can use this index according to the type of road (international road roughness) without any need to perform time-consuming jury tests. The metrics are correlated with jury test results that show which of them and how much has affected the acoustical comfort of the vehicle. The relation between road roughness and vehicle acoustical comfort index is another point of interest in this research. 相似文献
155.
E. Jimnez Kamal Abderrafi Juan Martínez-Pastor Rafael Abargues Jos Luís Valds Rafael Ibez 《Superlattices and Microstructures》2008,43(5-6):487
Metal nanoparticles can be prepared by a novel technique that consists of the laser ablation of a solid target immersed in a water solution of a metal salt. Silicon was chosen as the most adequate target to synthesize silver and gold nanoparticles from a water solution of either AgNO3 or HAuCl4. The influence of both the silver nitrate concentrations and the irradiation time of the Si target on the optical properties of the Au and Ag nanoparticles have been investigated. The crystalline nature of the metal nanoparticles has been determined by X-ray diffraction (XRD). Average size and particle size distribution have been measured by means of TEM. The absorbance spectra show the characteristic band of the surface resonant plasmon of silver and gold nanoparticles. 相似文献
156.
A novel Schiff base namely (E)-3-((2,6-dihydroxypyrimidin-4-ylimino)methyl)-4H-chromen-4-one and its Co (II), N (II)i, Cu (II) and Cd (II) complexes have been synthesized and proved by elemental analysis, molar conductance, thermal analysis (TGA), Inductive Coupled plasma (ICP), magnetic moment measurements, X-ray powder diffraction, IR, EI-mass,1H NMR, 13C NMR,UV–Vis. and ESR spectral studies. On the basis of these data, it is evident that the Schiff base acts as bidentate via oxygen atom of carbonyl group and azomethine nitrogen atom for Co (II) complex; monobasic bidentate ligand for Ni (II), Cu (II) and Cd (II) complexes via oxygen atom of hydroxyl group and nitrogen atom of pyrimidine ring. The results showed all complexes have octahedral geometry. The average particle size of the ligand and its complexes were found to be 1.010–0.343 nm. The pharmacological action (antioxidant, antimicrobial and anticancer) of the prepared compounds is studied. The antitumor activity of the ligand and its metal complexes is evaluated against human liver carcinoma (HEPG2) cell. The data displayed the Co (II) complexes strong cytotoxicity where IC50 values of Co (II) complex and 5-fluorouracil (stander drug) are 9.33 and 7.86 μg/ml respectively. The Co (II) and Cd (II) complexes have antibacterial activity more than ampicillin (stander drug). The interaction of the synthesized compounds with calf-thymus DNA (CT-DNA) has been performed via absorption spectra and viscosity technique. The DNA- binding constants have been determined. 相似文献
157.
TsNBr2 reacts with alkyne in the presence of methanol to form α,α-dibromodimethyl ketals instantaneously. The reaction proceeds smoothly at room temperature without using any other catalyst. The one step reaction can be carried out with both aromatic and aliphatic alkynes in excellent yield. 相似文献
158.
159.
Silver(I)‐Catalyzed Enantioselective [3+2]‐Cycloaddition Reaction of α‐Silylimines: A Facile Route to Quaternary‐Carbon‐Rich Scaffolds 下载免费PDF全文
Dr. Naredla Kesava‐Reddy Christopher Golz Prof. Dr. Carsten Strohmann Dr. Kamal Kumar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18373-18377
A silver‐catalyzed highly enantioselective 1,3‐dipolar cycloaddition reaction of α‐silylimines with pyrone‐based trisubstituted olefins was developed affording bi‐ and tricyclic α‐quaternary‐carbon‐rich pyrano‐pyrrolidines in excellent yields. The tricyclic benzopyrone adducts thus obtained were efficiently transformed into highly complex tetracyclic scaffolds supporting four consecutive stereogenic centers with three quaternary carbons. 相似文献
160.
Avinash K. Srivastava Munsaf Ali Kamal Nayan Sharma Raj K. Joshi 《Tetrahedron letters》2018,59(33):3188-3193
A toluene solution of β-chlorocinnamaldehyde and dihydroxy alcohols in the catalytic presence of para-toluenesulphonic acid (PTSA) yield the β-ketoacetal in good to outstanding amount. The catalyst (PTSA), first selectively protect the aldehydic group to form the β-chloroacetal and the subsequent dechlorination by H2O result the β-ketoacetal. Significant transformation was achieved with electron donating substituent attached at the para-position of cinnamaldehyde. The selective formation of β-keto-1,3-acetal was also obtained with a mixture of 1, 2- and 1, 3- diol. The present reaction consists of a metal-free, economical, robustly feasible, sizeable functional group tolerance and high yield properties. Moreover, the use of different dihydroxy alcohols made this process more benign and valuable towards the metal-free development of ketones. First, of its kind, a rare and unusual multitasking nature of PTSA is observed. 相似文献