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151.
In the determination of bismuth, Chelex 100 has been successfully employed for reducing the concentration of matrix and interfering elements from sulphide ores and concentrates and for separation of the matrix elements from bismuth in the analysis of high-purity copper, silver and silver-cadmium alloy. 相似文献
152.
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 下载免费PDF全文
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
153.
Fused Quinazolinoquinazolinones: Synthesis,Isomerization, Spectroscopic Identification,and Anticancer Activity 下载免费PDF全文
Somepalli Venkateswarlu Meka Satyanarayana Vijaybaskar Lakshmikanthan Vidavalur Siddaiah 《Journal of heterocyclic chemistry》2015,52(6):1631-1638
13H‐quinazolino[3,4‐a]quinazolin‐13‐ones have been synthesized from 2‐aminobenzamides in four steps. An acid‐catalyzed or base‐catalyzed isomerization of 13H‐quinazolino[3,4‐a]quinazolin‐13‐ones to 8H‐quinazolino[4,3‐b]quinazolin‐8‐ones in excellent yields (90–95%) has been reported. The differences in the infrared and nuclear magnetic resonance (1H & 13C) data of these isomeric fused quinazolinoquinazolinones afford a useful method for distinguishing between the two series. These analogs showed moderate anticancer activity (EGFR‐TK inhibition). 相似文献
154.
Highly regioselective ring opening of epoxides and aziridines using (bromodimethyl)sulfonium bromide
Epoxides and aziridines undergo ring opening efficiently with (bromodimethyl)sulfonium bromide at room temperature to form the corresponding β-bromohydrins and β-bromoamines, respectively. The conversions are highly regioselective and afford the products in excellent yields within a short period of time. 相似文献
155.
Dasari Ramesh Singanaboina Rajaram Manchala Narasimhulu Thummalpally Srikanth Reddy Kondempudi Chinni Mahesh Gajji Manasa Yenamandra Venkateswarlu 《中国化学》2011,29(11):2471-2475
An environmentally friendly and highly efficient procedure for the preparation of 1,4‐dihydropyridines by the reaction between α,β‐unsaturated aldehydes, aromatic amines and β‐keto esters in the presence of silica supported perchloric acid is described. 相似文献
156.
L. V. KrishnaRao D. V. Sathish Ch. Venkata Reddy U. S. Udayachandran Thampy K. Venkateswarlu P. S. Rao R. V. S. S. N. Ravikumar 《Applied magnetic resonance》2012,42(3):403-411
The Cr3+-doped cadmium oxide nanopowder is prepared at room temperature by a mild and simple solution method. The prepared powder
is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical, electron paramagnetic resonance
(EPR) and Fourier transform infrared (FT-IR) techniques. The XRD powder pattern reveals the lattice structure and cell parameters
are evaluated. The SEM image shows the stone-like morphology of the nanopowder. The optical absorption spectrum indicates
the distorted octahedral site symmetry of Cr3+ ions. The crystal field Dq and interelectronic repulsion parameters B and C are evaluated. The EPR spectrum gives a resonance signal at g = 1.973 for Cr3+ ions. The FT-IR spectrum reveals the characteristic vibrations of cadmium oxide. 相似文献
157.
Upper and lower bounds on the drag offered to a Newtonian fluid sphere placed in an Ellis model fluid in creeping flow have been found using variational principles. For a solid sphere, the bounds are in good agreement with those reported by earlier investigators. 相似文献
158.
K. Srihari Babu M. Raghavendar Rao G. Goverdhan P. Srinivas P. Pratap Reddy G. Venkateswarlu 《合成通讯》2013,43(13):1751-1758
Valganciclovir hydrochloride (1) is used for the treatment of cytomegalovirus (CMV) retinitis in patients with weakened immune systems. Valganciclovir hydrochloride is a hydrochloride salt of L-valyl ester of ganciclovir (2) that exists as a mixture of two diastereomers. According to the U.S. Food and Drug Administration specifications, the diastereomeric ratio of valganciclovir hydrochloride 1 should be maintained in the range 55:45 to 45:55. According to the U.S. Food and Drug Administration specifications, the diastereomeric ratio of valganciclovir hydrochloride 1 should be maintained in the range 55:45 to 45:55. During the process development of valganciclovir hydrochloride, six related substances (impurities) were observed along with the final active pharmaceutical ingredient. Among these six impurities, ganciclovir (2) and guanine (3) are the key starting materials and degraded impurities of ganciclovir, respectively. The remaining four impurities were identified as isovalganciclovir hydrochloride (4), methoxymethylguanine (5), O-acetoxy ganciclovir (6), and isovalarylganciclovir (7). The present work describes the synthesis and characterization of these four impurities. 相似文献
159.
160.