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61.
V. Krishnakumar Fazlur-Rahman Nawaz Khan Badal Kumar Mandal Sukanya Mitta Ramu Dhasamandha Vindhya Nanu Govindan 《Research on Chemical Intermediates》2012,38(8):1819-1826
The ethyl-2-chloroquinoline-3-carboxylates, 4, were achieved from o-aminobenzophenones in two steps. i.e. initially, the ethyl-2-oxoquinoline-3-carboxylates, 3, were obtained by base-catalyzed Friedlander condensations of o-aminobenzophenones, 1, and diethylmalonate, 2. The 2-chloroquinoline-3-carboxylates, 4, were then obtained by the reaction with POCl3 in good yields. The chemical structures were confirmed by FTIR, mass and 1H-NMR spectroscopic techniques. All the synthesized compounds were tested for their in vitro antibacterial activity against Bacillus subtilis and Vibrio cholera and found to possess moderate activity. 相似文献
62.
Evgenij Zubko Hiroshi Kimura Yuriy Shkuratov Karri Muinonen Tetsuo Yamamoto Hajime Okamoto Gorden Videen 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(14-16):1741-1749
We study the influence of material absorption on light scattering by agglomerated debris particles whose sizes are comparable with the wavelength. We find that the angular profile of linear polarization is extremely sensitive to the imaginary part of refractive index, and there are some unique features that may assist in the retrieval of physical properties of particles using remote-sensing techniques. Most notably, the position of the positive polarization maximum αmax changes monotonically with the imaginary part of refractive index, allowing it to be used to characterize this property. In addition, the amplitude of the negative polarization branch (NPB) is significantly greater for dielectric particles than for non-dielectric particles. It disappears in the transition region between dielectric and conducting particles before reappearing as the imaginary part of the refractive index is increased further. Further increasing the imaginary part of the refractive index may see the NPB disappearing and reappearing in quasi-periodic fashion. This recurrent NPB has a much smaller amplitude than that of dielectric particles. This suggests that the cometary circumnuclear haloes, which have significant NPBs, cannot contain significant quantities of absorbing particles. In addition, combined observations suggest that the polarization maximum of circumnuclear haloes are relatively small Pmax~12%, and occur at relatively small phase angles αmax~60°, which is also consistent with dielectric particles. 相似文献
63.
Jani Tyynelä Karri Muinonen Evgenij Zubko Gorden Videen 《Journal of Quantitative Spectroscopy & Radiative Transfer》2008,109(12-13):2207-2218
We investigate the single-scattering interference mechanism related to the negative polarization branch (NPB) and intensity enhancement branch (IEB) near the backscattering direction for wavelength-scale Gaussian-random-sphere particles. Previously, we showed that for wavelength-scale spherical particles there is a two-part mechanism related to the longitudinal and the transverse components of the internal electric fields that are responsible for producing both the NPB and IEB near the backscattering direction. For comparison with the previous study, we have chosen the ensemble-averaged parameters of the Gaussian-random-sphere particles to be equivalent to those for spherical particles. We conclude that the same mechanism also can explain the NPB and IEB for non-spherical particles and that the mechanism seems to be stronger inside spherical particles, mainly because of stronger interference, and becomes weaker as the particle becomes more non-spherical. 相似文献
64.
Sougandi Ilango Mahalakshmi Rajaram Kannappan Ramu Rajendiran Thekkelnayackanpatti M. Venkatesan Rangarajan Sambasiva Rao Pillutla 《Transition Metal Chemistry》2002,27(5):512-519
The synthesis, reduction, optical and e.p.r. spectral properties of a series of new binuclear copper(II) complexes, containing bridging moieties (OH–, MeCO2
–, NO2
–, and N3
–), with new proline-based binuclear pentadentate Mannich base ligands is described. The ligands are: 2,6-bis[(prolin-1-yl)methyl]4-bromophenol [H3L1], 2,6-bis[(prolin-1-yl)methyl]4-t-butylphenol [H3L2] and 2,6-bis[(prolin-1-yl)methyl]4-methoxyphenol [H3L3]. The exogenous bridging complexes thus prepared were hydroxo: [Cu2L1(OH)(H2O)2] · H2O (1a), [Cu2L2(OH)(H2O)2] · H2O (1b), [Cu2L3(OH)(H2O)2] · H2O (1c), acetato [Cu2L1(OAc)] · H2O (2a), [Cu2L2(OAc)] · H2O (2b), [Cu2L3(OAc)] · H2O (2c), nitrito [Cu2L1(NO2)(H2O)2] · H2O (3a), [Cu2L2(NO2)(H2O)2] · H2O (3b), [Cu2L3(NO2)(H2O)2] · H2O (3c) and azido [Cu2L1(N3)(H2O)2] · H2O (4a), [Cu2L2(N3)(H2O)2] · H2O (4b) and [Cu2L3(N3)(H2O)2] · H2O (4c). The complexes were characterized by elemental analysis and by spectroscopy. They exhibit resolved copper hyperfine e.p.r. spectra at room temperature, indicating the presence of weak antiferromagnetic coupling between the copper atoms. The strength of the antiferromagnetic coupling lies in the order: NO2 N3 OH OAc. Cyclic voltammetry revealed the presence of two redox couples CuIICuII CuIICuI CuICuI. The conproportionality constant K
con for the mixed valent CuIICuI species for all the complexes have been determined electrochemically. 相似文献
65.
Yatish Kalanakoppal Venkatesh Mithun Prakash Ravikumar Shwetharani Ramu Chandan Hunsur Ravikumar Sakar Mohan R. Geetha Balakrishna 《Chemical record (New York, N.Y.)》2023,23(12):e202300277
Biodiesel represents a biodegradable, environmentally friendly, and renewable alternative to fossil fuels. Despite more than three decades of research, significant obstacles still hinder the widespread production of biodiesel. This current review elucidates both the potential and the existing challenges associated with homogeneous and heterogeneous catalysts in catalyzing biodiesel production, with a particular focus on alkali analogues, alkaline earth metal oxides, and titania-based catalysts. In particular, a comprehensive analysis is presented concerning alkali and alkaline earth-based titania (TiO2) catalysts. Among these, the alkaline earth metal oxides, including lithium, calcium, and strontium when combined with titanium-based catalysts, exhibit superior catalytic activity compared to other metal oxides, owing to their heightened basicity. Consequently, this review offers a thorough and up-to-date insight into the potential of titania-based heterogeneous catalysts for advancing biodiesel production. 相似文献
66.
Ravi Varala Ramu Enugala Srinivas R. Adapa 《Monatshefte für Chemie / Chemical Monthly》2008,32(6):1369-1372
Ruthenium(III) chloride (1 mol%) alone can catalyze the insertion of ethyl diazoacetate into N–H bonds of various structurally
and electronically diverse secondary cyclic amines under solvent-free conditions to afford the corresponding glycine esters
in good yields under ambient conditions. Reactions with various aliphatic primary and aromatic amines examined, however, were
unsuccessful. 相似文献
67.
E. Rajanarendar K. Ramu D. Karunakar P. Ramesh 《Journal of heterocyclic chemistry》2005,42(4):711-715
Trimolecular condensation of N‐(3‐meihyl‐5‐styryl‐isoxazol‐4‐yl)‐N'‐aryl thioureas ( 2 ), paraformaldehyde and primary amines using montmorillonite K‐10 in dry media under microwave irradiation leads to isoxazolyl triazinethiones ( 3 ) in high yield. Condensation of 2 with paraformaldehyde alone under similar conditions provide isoxazolyl oxadiazinethiones ( 4 ) in excellent yield. 相似文献
68.
Bioanalysis of tolvaptan,a novel AVP‐V2 receptor antagonist in human plasma by a novel LC‐ESI‐MS/MS method: a pharmacokinetic application in healthy South Indian male subjects
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Venkata Ramu Derangula Nageswara Rao Pilli Babu Rao Bhukya Chalapathi Rao Pulipati Vinayender Adireddy Venkateswarlu Ponneri 《Biomedical chromatography : BMC》2014,28(3):332-340
A simple, rapid and sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC‐ESI‐MS/MS) assay method is proposed for the determination of tolvaptan in human plasma samples using tolvaptan d7 as internal standard (IS). Analyte and the IS were extracted from 100 μL of human plasma via simple liquid–liquid extraction. The chromatographic separation was achieved on a C18 column using a mixture of methanol and 0.1% formic acid buffer (80:20, v/v) as the mobile phase at a flow rate of 1.0 mL/min. The calibration curve obtained was linear (r2 ≥ 0.99) over the concentration range of 0.05–501 ng/mL. Method validation was performed as per US Food and Drug Administration guidelines and the results met the acceptance criteria. The intra‐day and inter‐day precision (coefficient of variation) and accuracy results in three validation batches across five concentration levels were well within the acceptance limits. A run time of 2.0 min for each sample made it possible to analyze more samples in a short time, thus increasing the productivity. The proposed method was successfully applied to a pharmacokinetic study of 15 mg and 60 mg tolvaptan tablet formulation in healthy South Indian male subjects under fasting condition. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
69.
70.
Vinayender Adireddy Nageswara Rao Pilli Venkata Ramu Derangula Shobha Rani Satla Chinna Veera Badraiah Ganguri Venkateswarlu Ponneri 《Biomedical chromatography : BMC》2013,27(8):1062-1069
This paper describes a simple, rapid and sensitive liquid chromatography/tandem mass spectrometry assay for the determination of aliskiren in human plasma using nevirapine as an internal standard. Analyte and the internal standard were extracted from 100 μL of human plasma via liquid–liquid extraction using tert‐butyl methyl ether. The chromatographic separation was achieved on a C18 column using a mixture of acetonitrile and 0.1% formic acid (90:10, v/v) as the mobile phase at a flow rate of 0.9 mL/min. The calibration curve obtained was linear (r2 ≥ 0.99) over the concentration range of 0.10–1013 ng/mL. Method validation was performed as per US Food and Drug Administration guidelines and the results met the acceptance criteria. A run time of 2.2 min for each sample made it possible to analyze a greater number of samples in a short time, thus increasing the productivity. The proposed method was found to be applicable to clinical studies. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献