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21.
A rapid, sensitive and selective method is described for the determination of chromium(VI) in presence of 100-fold amounts of chromium(III) by flame atomic absorption spectrometry (FAAS) in conjunction with coprecipitative preconcentration of its ethyl xanthate complex onto naphthalene. The solid mixture consisting of the chromium(VI) complex together with naphthalene is dissolved in 8.0 ml of dimethyl formamide (DMF) and chromium(VI) content was established by FAAS. Calibration graphs were rectilinear over the chromium(VI) concentration in the range 0-200 μg l−1. Five replicate determinations of 20 μg of chromium(VI) present in 1.0 l of sample solution gave a relative standard deviation of 3.1%. The detection limit corresponding to three times the standard deviation of the blank was found to be 0.5 μg l−1. The developed procedure has been successfully utilized for the estimation of chromium(VI), chromium(total) (after oxidation with bromate) and chromium(III) (by subtracting chromium(VI) content from chromium(total) value contents of several tannery industries. 相似文献
22.
Sridevi Nadimpalli Rambabu Rallabandi Dikshitulu S. A. Lanka 《Transition Metal Chemistry》1990,15(3):191-196
Summary The kinetics of CoIII oxidation of SeIV have been studied in aqueous HClO4. The order with respect to Com is two the order with respect to SeIV is one at low concentrations; two at high concentrations. The latter variation is attributed to the greater reactivity of the SeIV dimier A mechanism involving complexation between oxidant and substrate is proposed. [CoOH]2+ is presumed to be the reactive CoIII species and H2SeO3 and HSeO
3
–
to be those of SeIV. At 25° C, Ea, H and S for the monomeric path are 125.6±4.0 kJ mol–1, 122.1±3.8 kJ mol–1 and 206±12 JK–1 mol–1 respectively and those for the dimeric path are 88.6±3.6 kJ mol–1, 85.9±3.4 kJ mol–1 and 62.6±11.3 JK–1 mol–1 respectively. 相似文献
23.
A direct access to 3-(2-Oxoalkyl)indoles via aluminum chloride induced C-C bond formation 总被引:1,自引:0,他引:1
3-Methylindole is acylated regioselectively at the methyl group when treated with a variety of acyl chlorides in 1,2-dichloroethane in the presence of AlCl(3), affording a mild and direct method for the synthesis of 3-(2-oxoalkyl)indoles. The product formation in this one-pot reaction largely depends on the conditions of the reaction employed. The methodology does not require protection-deprotection steps and is amenable for the scale-up synthesis of these indole derivatives. 相似文献
24.
Hydroxy-rhodium catalyzed dimerization of various cyclic enones to the corresponding α-enone adducts is developed. The key feature of this method is that the base-sensitive, highly substituted enones also undergo dimerization and the resultant products are obtained in moderate to good yields. 相似文献
25.
Sakram B. Ashok K. Rambabu S. Sonyanaik B. Ravi D. 《Russian Journal of General Chemistry》2017,87(8):1794-1799
Russian Journal of General Chemistry - Synthesis of substituted 1,8-naphthyridines based on 2-aminonicotinaldehyde under mild conditions is studied. Out of three electrophilic iodine sources (I2,... 相似文献
26.
27.
Darsi Rambabu Mohammad Ashraf Ankush Gupta Abhimanew Dhir 《Tetrahedron letters》2017,58(50):4691-4694
We have synthesised new Mn-MOF@Pi composite by encapsulation of piperidine in desolvated Mn-MOF and investigated its catalytic performance in Knoevenagel condensation reaction. The newly developed composite is compatible with various aromatic aldehydes and converting them to the desired Knoevenagel condensation products in good yields and selectivity. Furthermore, composite Mn-MOF@Pi is reusable and shows good catalytic activity than native MOF. 相似文献
28.
Balakrishna Dulla E. Sailaja Upendar Reddy CH Madhu Aeluri Arunasree M. Kalle S. Bhavani D. Rambabu M.V. Basaveswara Rao Manojit Pal 《Tetrahedron letters》2014
Indole based novel small molecules were designed as potential anticancer agents. Multi step synthesis of these compounds was carried out by using Pd/C–Cu mediated coupling–cyclization strategy as a key step. The single crystal X-ray diffraction study was used to confirm the molecular structure of a representative compound unambiguously. Many of these compounds were evaluated for their anti-proliferative properties in vitro against six cancer cell lines as well as noncancerous cells. All these compounds showed selective growth inhibition of cancer cells and several of them were found to be promising with IC50 values in the range of 0.1–1.2 μM, comparable to the known anticancer drug doxorubicin. 相似文献
29.
Srivari Chandrasekhar Vidyavathi Patro Lahu N. Chavan Rambabu Chegondi René Grée 《Tetrahedron letters》2014
An efficient and eco-friendly method for the synthesis of substituted pyrroles has been developed via ruthenium-catalyzed multicomponent reaction of ketone, amine, and ethylene glycol in PEG-400 as solvent medium without using any external ligand. The catalytic system and solvent can be recycled with the same, as well as different, ketones with minimum loss of Ru-catalyst activity. 相似文献
30.
D. Rambabu S. N. Mishra R. G. Pillay A. K. Grover P. N. Tandon 《Hyperfine Interactions》1987,34(1-4):533-536
The magnetic and57Fe Mössbauer studies in melt-spun RuFeSi show that in spite of the differences in the Xac responses between the melt-spun and annealed specimens, which have very different atomic order/disorder, the microscopic details of the Fe spin dynamics are similar. The melt-spun sample does not show reentrant like bulk magnetic behaviour in contrast to the annealed specimens. 相似文献