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81.
82.
Vaneet K. Sharma Sonam Bansal Ashok K. Malik † Rakesh K. Mahajan 《International journal of environmental analytical chemistry》2013,93(14-15):1105-1110
A procedure has been developed for the direct fourth derivative spectrophotometric determination of zinc(II) dimethyldithiocarbamate by converting it into its copper(II) dimethyldithiocarbamate complex, which is then dissolved in Triton X-100. Beer's law is obeyed over the concentration range 0.5–30?µg/mL in the final solution. Various parameters such as the effect of pH and the interference of a number of ions on the determination of Ziram have been studied in detail. The method is sensitive and can be used for the determination of Ziram in commercial samples like Zirax and Ziron containing Ziram and from wheat grains. 相似文献
83.
84.
Thiosemicarbazone (1) of dehydroacetic acid (DHAA) reacts smoothly with α-haloketones to yield corresponding thiazolylhydrazones (2) of DHAA, which on refluxing in EtOH-AcOH rearrange to the title compounds (3). 相似文献
85.
Hitendra S. Mahajan Mayur H. Pingale Kapil M. Agrawal 《Journal of inclusion phenomena and macrocyclic chemistry》2013,76(3-4):467-472
The objective of the present study was to formulate inclusion complex of saquinavir mesylate to improve the aqueous solubility and dissolution rate. Saquinavir mesylate is a BCS class II drug having low aqueous solubility and therefore low oral bioavailability. In the present study, inclusion complex of saquinavir mesylate with hydroxypropyl-β-cyclodextrin were prepared by kneading method. Inclusion complex were characterized by differential scanning calorimetry (DSC), X-ray diffractometry (XRD), 1H NMR studies, and Fourier transform infrared spectroscopy and evaluated for in vitro dissolution, and phase solubility studies. DSC and XRD study demonstrated that there was a significant decrease in crystallinity of pure drug present in inclusion complex, which resulted in an increased dissolution rate of saquinavir mesylate and 1H NMR studies strongly, confirmed that the inclusion complex has formed. Inclusion complexation results in improvement in solubility and dissolution rate. The inclusion complexation would be suitable method for dissolution and bioavailability enhancement of saquinavir mesylate. 相似文献
86.
The cloud point (CP) studies on aqueous solutions of two ethylene oxide-propylene oxide triblock copolymers (EO)2.5(PO)31(EO)2.5 and (EO)13(PO)30(EO)13 with varying number of ethylene oxide (EO) units were carried out in the presence of series of additives, such as alkali,
acids, ionic surfactants, alcohols, salts, and hydrotropes. The results of this study show that sodium hydroxide decreases
the CP of the two copolymers. Acids increase the CP in the order hydrochloric acid > acetic acid > formic acid for both the
triblock copolymers. Hydrotropes increase the CP, whereas salts decrease or increase the CP based on their salting-out/salting-in
nature. Alcohols, which are polar organic additives, affect the CP of the two copolymers differently. The change in the CP
of the triblock copolymers depends upon the structure and concentration of the additives and on the number of EO units of
the two triblock copolymers. 相似文献
87.
AbstractRhodium-catalyzed intermolecular [3?+?2+2] cycloaddition reactions of bis(methylenecyclopropanes) with different alkynes are described. The rhodium-catalyzed [3?+?2+2] cycloadditions resulted in the formation of functionalized 5–7–3 spirocyclic carbocycles in moderate yields with excellent regio- and chemo-selectivity. 相似文献
88.
P. S. Makashir R. R. Mahajan J. P. Agrawal 《Journal of Thermal Analysis and Calorimetry》1995,45(3):501-509
The thermal decomposition of nitrocellulose (NC) 12.1% N, has been studied with regard to kinetics, mechanism, morphology and the gaseous products thereof, using thermogravimetry (TG), differential thermal analysis (DTA), IR spectroscopy, differential scanning calorimetry (DSC) and hot stage microscopy. The kinetics of the initial stage of thermolysis ofNC in condensed state has been investigated by isothermal high temperature infrared spectroscopy (IR). The decomposition ofNC in KBr matrix in the temperature range of 142–151°C shows rapid decrease in O?NO2 band intensity, suggesting that the decomposition of NC occurs by the rupture of O?NO2 bond. The energy of activation for this process has been determined with the help of Avrami-Erofe'ev equation (n=1) and is ≈188.35 kJ·mol?1. Further, the IR spectra of the decomposition products in the initial stage of thermal decomposition ofNC, indicates the presence of mainly NO2 gas and aldehyde. 相似文献
89.
Monika Swami Karuna Mahajan Neeti Gupta R. V. Singh Sunita Arya Sonalika Kushwah 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):2125-2139
The present article describes the synthesis and characterization of tetracoordinated boron (III) complexes with monobasic bidentate ligands (L 1 H, L 2 H, L 3 H, L 4 H, L 5 H, and L 6 H) having the general formulae PhB(L)(OH) and PhB(L) 2 . The 1:1 and 1:2 reactions of phenyl boronic acid with monobasic bidentate ligands resulted in the formation of colored solids. The complexes have been characterized by elemental analysis, molecular weight determinations, and IR and NMR ( 1 H, 13 C and 11 B) spectroscopy, as well as UV-vis spectral studies. Based on these studies, a tetrahedral geometry has been proposed for the resulting complexes. The ligands, along with their complexes, have been screened in vitro against a number of pathogenic fungal and bacterial strains. The studies indicate that the boron chelates are more potent than the parent ligands. 相似文献
90.
Karuna Mahajan Monika Swami R. V. Singh 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2664-2679
Tetra- and pentacoordinated antimony and bismuth derivatives have been prepared by the interactions of monophenylantimonydichloride(III), trichlorostibane, and trichlorobismuthane with the sodium salts of 3-(indolin-2-one)hydrazinecarbothioamide (L1H) and 3-(indolin-2-one)hydrazinecarboxamide (L2H), under microwave irradiation as well as by conventional heating. These compounds were further characterized by analytical and spectroscopic techniques including UV, IR, 1H NMR, and 13C NMR spectra. Newly synthesized complexes with their corresponding ligands were also tested for their antifungal and antibacterial activities. 相似文献