排序方式: 共有16条查询结果,搜索用时 20 毫秒
1.
2.
M. S. Attia A. O. Youssef Abdel-Sattar S. H. Elgazwy Samia A. El Abady Samia M. Agami Safaa I. Elewa 《Journal of fluorescence》2014,24(3):759-765
The sensitization of the excited triplet state of a novel symmetrical Bis(dialkylamino)phenoxazinium salt was developed in the presence of Hg2+. This effect was used to determine the concentration of Hg2+ in different water samples. The phenoxazinium salt sensor was characterized by different spectroscopic tools such as: UV, FTIR, NMR and fluorescence spectra. The sensor has an emission band at 347 nm in DMSO. Hg2+ in DMSO at pH 5.6 can remarkably quench the fluorescence intensity of the sensor at 347 nm and a new band was appeared at 436 nm due to the strong complex formation between Hg2+ and sensor. The quenching of the band intensity at 347 and the enhancement of the intensity of the new band at 436 were used to determine the Hg2+ in different waste water samples. The dynamic range found for the determination of Hg2+ concentration is 8.7?×?10-10 – 1.4?×?10-6 mol L?1 with a detection limit of 5.8?×?10?10 mol L?1 and quantification detection limit of 1.8?×?10-9 mol L-1. 相似文献
3.
Elgazwy AS 《Chemistry Central journal》2012,6(1):50
ABSTRACT: In vitro antitumor evaluation of the synthesized 46 compounds of 3,5-diaryl-4,5-dihydropyrazoles against EAC cell lines and 3D QSAR study using pharmacophore and Comparative Molecular Field Analysis (CoMFA) methods were described. CoMFA derived QSAR model shows a good conventional squared correlation coefficient r2 and cross validated correlation coefficient r2 cv 0.896 and 0.568 respectively. In this analysis steric and electrostatic field contribute to the QSAR equation by 70% and 30% respectively, suggesting that variation in biological activity of the compounds is dominated by differences in steric (van der Waals) interactions. To visualize the CoMFA steric and electrostatic field from partial least squares (PLS) analysis, contour maps are plotted as percentage contribution to the QSAR equation and are associated with the differences in biological activity. BACKGROUND: Pyrazole derivatives exhibit a wide range of biological properties including promising antitumor activity. Furthermore, Aldol condensation assisted organic synthesis has delivered rapid routes to N-containing heterocycles, including pyrazoles. Combining these features, the use of chalconisation-assisted processes will provide rapid access to a targeted dihydropyrazoles library bearing a hydrazino 3D QSAR study using pharmacophore and Comparative Molecular Field Analysis (CoMFA) methods were described for evaluation of antioxidant properties. RESULTS: Chalcones promoted 1 of the 2 steps in a rapid, convergent synthesis of a small library of hydrazinyl pyrazole derivatives, all of which exhibited significant antitumor activity against Ehrlich Ascites Carcinoma (EAC) human tumor cell line comparable to that of the natural anticancer doxorubicin, as a reference standard during this study. In order to understand the observed pharmacological properties, quantitative structure-activity relationship (3D QSAR) study was initiated. CONCLUSIONS: Chalcones heating provides a rapid and expedient route to a series of pyrazoles to investigate their chracterization scavenging properties. Given their favorable properties, in comparison with known anticancer, these pyrazole derivatives are promising leads for further development and optimization. 相似文献
4.
Four alkaloids of the phenethylamine derivatives have been isolated from the n-butanol fraction of the aerial parts of Stapelia hirsuta L. The structures of the isolated alkaloids were determined as N-acetyl hordenine (a new natural compound), hordenine, candicine and hordenine-1-O-beta-D-glucoside, in addition to luteolin-7-O-beta-D-glucopyranoside. 相似文献
5.
Essam Abdel-Sattar 《Monatshefte für Chemie / Chemical Monthly》2001,11(3):1095-1099
The reinvestigation of the CH2Cl2 extract of the aerial parts of Conyza incana led to the isolation of three minor alicyclic diterpene acids. The structures of the new compounds were established by a
combination of spectroscopic methods. 相似文献
6.
Abdel-Sattar S. Hamad Dieter Schinzer 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):187-199
Abstract (R) and (S) of 2-Methy1-3-oxa-5-(tert-butyldiphenylsilyloxyl)methy1pentanoate (4a. 6a) and (R) and (S) of 2-methy1-3-oxa-5-(tert-butyldimethylsilyloxyl)methylpentanoate (4b, 6b) were synthesized by the reaction of the preparative compounds (2a, 2b) with (R) and (S) methy1lactate (3, 4) in the presence of a silver (1) oxide catalyst (Method B). The title compounds are useful for the synthesis of different natural products such as epothilones. 相似文献
7.
Abdel-Sattar E Harraz FM Ghareib SA Elberry AA Gabr S Suliaman MI 《Natural product research》2011,25(12):1171-1179
The antihyperglycaemic and hypolipidaemic effects of the methanolic extract of Caralluma tuberculata were investigated in streptozotocin (STZ)-induced diabetic rats. The antihyperglycaemic activity was assessed by the reduction in fasting blood glucose (54% at 4th week) and the peak of blood glucose at 120?min of an oral glucose tolerance test in diabetic rats. Further, the tested extract also increased plasma insulin by 206.8%. The hypolipidaemic action of the extract was evident by the significant decrease in the levels of total cholesterol, triglycerides and LDL-cholesterol by 41.5%, 36.7% and 49.1%, respectively, compared to diabetic rat values. Interestingly, the extract increased the cardio-protective lipid HDL-cholesterol by 147.97% as compared to diabetic rat value. The present data suggests that the methanolic extract of C. tuberculata has both antihyperglycaemic and hypolipidaemic effects in STZ-induced diabetic rats that may need further studies to be used in the management of diabetes and associated hyperlipedaemia. 相似文献
8.
Abdel-Sattar S. Hamad Elgazwy 《Polyhedron》2009,28(17):3667-3674
3-(2-Chloroquinolin-3-yl)-1,5-bis(3,4,5-trimethoxy-phenyl)-pentane-2,4-dione derivatives 3a–b were conveniently synthesized in excellent yields (82% each) by tandem Knoevenagel condensation reactions of 2-chloro-3-carbaldehyde-quinoline 1a–b with 3,4,5-trimethoxy acetophenone, followed by a base catalyzed Michael addition, such as DBU (1,8-diazabicyclo[5,4,0]undec-7-ene) with or without solvent. The reactions of 3a–b with Pd(dba)2 in the presence of PPh3 (1:2) in degassed acetone provided the dinuclear palladium complexes {Pd(C,N-2-C9H4N–CH–[–CH2CO(3,4,5-(OMe-)3–C6H2-]2–3-R-6)Cl(PPh3)}2 [(R = H (4a), R = OMe (4b)] in moderate yields (38% and 43%), which in turn reacted with an excess of isonitrile XyNC (Xy = 2,6-Me2C6H3) to give the corresponding palladacycles 5a–b in moderate yields (45% and 43%). The palladacycles 5a–b were also obtained in similar yields (32% and 33%) via a one-pot oxidative addition reaction of 3a-b with isonitrile XyNC:Pd(dba)2 (4:1). The products were characterized by satisfactory elemental analysis and spectral studies (IR, 1H, and 31P NMR). The crystal structure of 5a was determined by X-ray crystallography diffraction studies. 相似文献
9.
Abdel-Sattar S. Hamad ElgazwyAuthor Vitae 《Tetrahedron》2003,59(38):7445-7463
10.
Synthesis of 5-spirocyclohexyl-2,4-dithiohydantoin derivatives: a potential anti-leishmaniasis agent
Abdel-Sattar S. Hamad Elgazwy Saad R. Atta-Allha Sherif M. A. S. Keshk 《Monatshefte für Chemie / Chemical Monthly》2009,1(1):243-249