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排序方式: 共有434条查询结果,搜索用时 15 毫秒
91.
Saeidian Hamid Sadighian Hamed Arabgari Masomeh Mirjafary Zohreh Ayati Seyed Ebrahim Najafi Ezzatollah Moghaddam Firouz Matloubi 《Research on Chemical Intermediates》2018,44(1):601-612
Research on Chemical Intermediates - We report robust green synthesis of novel 1,2,3-triazole-based sulfonamides bearing different motifs such as fluorine under click conditions in presence of a... 相似文献
92.
Ferhat Can Özkaya Weaam Ebrahim Maximilian Klopotowski Zhen Liu 《Natural product research》2018,32(7):840-843
The anti-neuroinflammatory meroterpenoid citreohybridonol was isolated for the first time from a sponge-derived fungus Penicillium atrovenetum. In this study, in addition to isolation and structure featuring, its unambiguous absolute configuration was determined exclusively by single crystal X-ray diffraction. The C-17-keto tautomer was clearly observed in X-ray analysis. The substance crystallises in the monoclinic space group P21 with a = 10.7496(5) Å, b = 14.3286(7) Å, c = 17.4909(8) Å, β = 103.235(2)°, V = 2622.5(2) Å3, Z = 2, Dcalcd = 1.280 g/cm3. The chirality of the asymmetric carbon atoms was as follows: C3 (S), C5 (R), C6 (S), C8 (S), C9 (R), C10 (R), C13 (R), C14 (R). 相似文献
93.
A highly selective and sensitive anodic stripping differential pulse polarographic method has been developed for the determination of trace amount of bismuth in various samples after adsorption of its 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol complex on amberlite XAD-2 resin in the pH range of 2.0-3.0. The retained analyte on the resin recovered with 10.0 ml of 2 M hydrochloric acid and bismuth is determined by anodic stripping differential pulse polarography. In this case, 0.15 μg of bismuth can be concentrated in the column from 1100 ml of aqueous sample, where its concentration is as low as 0.14 ng ml−1 and the linearity is maintained in the concentration range 0.05-160 μg ml−1 in final solution with a correlation coefficient of 0.999 and relative standard deviation of ±1.2%. Various parameters such as the effect of pH, flow rate, and interference of number of metal ions on the determination of bismuth have been studied in detail to optimize the conditions for determination of bismuth in standard alloys: Nippon Keikinzoku Kogyo (NKK CRM No. 916 aluminum alloy); (NKK CRM No. 1021 Al, Si, Cu, Zn alloy); and (NKK CRM No. 920 aluminum alloy), biological samples: National Institute for Environmental Studies (NIES, No. 5 human hair; NIES, No. 7 tea leaves) and water samples: (spring water, river water; Kerman water; and Shiraz water). 相似文献
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Ebrahim Karkhaneei Mohammad Hasan Zebarjadian Mojtaba Shamsipur 《Journal of solution chemistry》2001,30(4):323-333
[7Li] NMR measurements were used to determine the stoichiometry and stability of Li+ complexes with 18-crown-6 and dicyclohexyl-18-crown-6 in nitromethane and acetonitrile solutions. A competitive [7Li] NMR technique was also employed to probe the complexation of Ba2+, Pb2+, Cd2+, and UO22+ ions with the same crown ethers–solvent systems. All the resulting 1 : 1 complexes were more stable in nitromethane than acetonitrile solution. In all cases, the stability of both crown complexes in nitromethane and acetonitrile varied in the order Pb2+ > Ba2+ > Li+ > Cd2+ > UO22+. 相似文献
96.
Substituted 5-Antipyrinylazo-4-phenyl-2-aminothiazoles as Disperse Dyes for Dyeing Polyester Fabrics
Mohamed A. Metwally Amira Metwally Ebrahim Abdel-Galil Fathy A. Amer 《Monatshefte für Chemie / Chemical Monthly》2008,139(1):35-42
Summary. A series of some new substituted 5-antipyrinylazo-4-phenyl-2-aminothiazole disperse dyes was synthesized by diazocoupling
of 4-antipyrinyldiazonium chloride with aminothiazole derivatives. The synthesized dyes were characterized by UV-Vis absorption,
IR, 1H NMR, and MS spectroscopy. The dyes gave orange to reddish-violet shades with very good depth and levelness when applied
to polyester fabrics as disperse dyes and their fastness properties were evaluated on polyester fibers. Also the position
of color in CIELAB coordinates (L*, a*, b*, H*, and C*) was assessed. 相似文献
97.
p‐Toluenesulfonic acid catalyzed the one‐pot, three‐component synthesis of 3‐aminoimidazo[1,2‐a]pyridines and pyrazines through a condensation reaction of a 2‐aminoazine, an aldehyde, and an isocyanide at room temperature. This methodology affords a number of 3‐aminoimidazo[1,2‐a]pyridines in reasonable yields and short reaction times without any significant optimization of the reaction conditions. 相似文献
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