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排序方式: 共有377条查询结果,搜索用时 15 毫秒
41.
Kalawati Meena Sudesh Kumari Jitender M. Khurana Amita Malik Chetan Sharma Harsh Panwar 《中国化学快报》2017,28(1):136-142
A simple and efficient three component procedure has been developed for the synthesis of highly substituted spiro[indolo-3,10'-indeno[1,2-b]quinolin]-2,4,11'-triones by one pot three component condensation of enaminones, isatin and indane-1,3-dione in ethanol:water (1:1) in presence of ceric ammonium nitrate (CAN) as catalyst. This method provides several advantages such as lesser reaction time, high yield of products and operational simplicity. The antimicrobial activity of some of the compounds has been investigated against six microbial strains, some of the tested compounds showed good antimicrobial activity. 相似文献
42.
N. Kumar S. K. Jha S. S. Chaturvedi 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(3):525-533
Radiation dose-risk assessment was carried out for cereal species Brassica compestris var. dichotoma, Oryza sativa var. Shalum1, Zea mays, Lactuca indica, Cumunis sativum, and Clocasia esculanta due to naturally available radionuclides 40K, 238U and 232Th in Domiasiat area. The activity in biota and corresponding soil was measured by precipitation method using NaI(TI) detector.
Transfer factor (TF) was for Oryza spp. (1.00E−01-40K, 8.76E−05-232Th, and 9.11E−05-238U), for Brassica spp. (5.39E−01-40K, 8.17E−04-232Th and 2.96E−04-238U) and for Zea spp. (3.41E−01-40K, 5.84E−05-232Th, 8.87E−05-238U) etc., respectively. A detailed physio-morphological study of the biota and extensive investigation of ecosystem was carried
out for assessment. The data was modeled using FASSET for dose estimation and obtained total dose was 1.58E−04
\upmu Gy h-1 \upmu \hbox{Gy}\,h^{-1} in Oryza spp., 2.87E−04
\upmu Gy h-1 \upmu \hbox{Gy}\,h^{-1}
Brassica spp. and 6.90E−03
\upmu Gy h-1 \upmu \hbox{Gy}\,h^{-1} in Zea spp. etc. The dose was compared with the UNSCEAR dataset for screening level dose for biota. Zea spp. was more susceptible for the chronic radiation exposure. 相似文献
43.
Athimoolam M Lakshmanan R Alwarappan S 《The journal of physical chemistry. A》2011,115(40):10950-10961
A mathematical model corresponding to homogeneous chemical reactions under transient chronoamperometry conditions at hemispherical microelectrodes has been developed. The analytical solutions for the concentration of species and current were obtained using Duhamel's theorem. This closed-form theoretical expression pertains to the transient concentration profiles and fluxes of chemical species involved in chemical and electrochemical reactions at hemispherical microelectrodes. As t → ∞, the analytical expressions corresponding to the concentration and current approach steady-state values. The solutions obtained are explicit only under limiting current conditions. The approximate expressions for concentrations and current as functions of time corresponding to the EC' and CE mechanisms at hemispherical microelectrodes are also reported. 相似文献
44.
A. K. Chaturvedi D. Chaturvedi N. Mishra V. Mishra 《Journal of the Iranian Chemical Society》2011,8(2):396-400
A novel Mitsunobu-based protocol has been developed for the synthesis of carbazates and dithiocarbazates through the variety of corresponding primary, secondary and tertiary alcohols and various kinds of substituted hydrazines using Mitsunobu??s reagent and CO2/CS2 system, in good to excellent yields. 相似文献
45.
R. K. Sinha A. Dhal P. Agarwal S. Kumar Monika B. B. Singh R. Kumar P. Bringel A. Neusser R. Kumar K. S. Golda R. P. Singh S. Muralithar N. Madhavan J. J. Das K. S. Thind A. K. Sinha I. M. Govil R. K. Bhowmik J. B. Gupta P. K. Joshi A. K. Jain S. C. Pancholi L. Chaturvedi 《The European Physical Journal A - Hadrons and Nuclei》2006,29(2):253-253
46.
R Nageswara Rao S Meena D Nagaraju A Raghuram Rao S Ravikanth 《Analytical sciences》2006,22(9):1257-1260
A simple and rapid reversed-phase high-performance liquid-chromatographic method for the separation and determination of process-related impurities of celecoxib (CXB) in bulk drugs and pharmaceuticals was developed. The separation of impurities viz., 4-methylacetophenone (I), 1-(4-methylphenyl)-4,4,4-trifluorobutane-1,3-dione (II), 4-hydrazinobenzene sulfonamide (III) and a regio-specific isomer [3-(4-methylphenyl)-5-trifluoromethyl-1H-pyrazole-1-yl]-benzenesulfonamide (IV), was accomplished on an Inertsil ODS-3 column dynamically coated with 0.1% hexamethyldisilazane (HMDS) in acetonitrile:water (55:45 v/v) as a mobile phase and detection at 242 nm using PDA at ambient temperature. The chromatographic conditions were optimized by studying the effects of HMDS, an organic modifier, time of silanization and column temperature. The method was validated and found to be suitable not only for monitoring the synthetic reactions, but also to evaluate the quality of CXB. 相似文献
47.
A novel process for the one-step conversion of a variety of primary and secondary alcohols into their O-alkyl-S-methyl dithiocarbonates using methyl iodide catalyzed by the Triton-B/CS2 system was developed. Thus, O-alkyl-S-methyl dithiocarbonates were obtained in very good to excellent yields. This protocol is mild and efficient compared to other
methods. 相似文献
48.
The reduction of thorium at the dropping mercury electrode in presence of ethylene bis(3-mercaptopropionate) has been found to be irreversible and kinetically controlled. The kinetics of the electrode reaction has been investigated adopting the treatment followed byKoutecky.
Mit 1 Abbildung 相似文献
Mit 1 Abbildung 相似文献
49.
Schiff base derivatives of the type Ph3Si? O? Sb(NO)Ph3 (where NO represents the donor system of a monobasic bidentate ligand) have been synthesized. These are obtained as coloured solids; they are non-electrolytes and monomeric in nature, and have been characterized by elemental analysis, IR and 1H NMR. Spectral studies suggest that silicon and antimony atoms are in tetra- and hexa-coordinated states, respectively. 相似文献
50.
A novel process for the one-step chemoselective conversion of alkyl halides into dithiocarbamates as protected amines was
developed using benzyltrimethylammonium hydroxide (Triton-B) in presence of carbon disulfide. Thus, dithiocarbamates of different
amines were prepared in very good to excellent yields. This protocol is mild, chemoselective, and efficient compared to other
methods. 相似文献