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51.
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
52.
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
53.
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
54.
55.
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
56.
A short synthesis of hydroxyethylene dipeptide isostere, a core unit of the HIV-protease inhibitors ritonavir and lopinavir, its C-3 epimer and C2 symmetric diamino diol is described. The crucial aspects of the synthesis are self-cross metathesis and exploitation of C2-symmetric of the metathesis product 8 to obtain the required skeleton. 相似文献
57.
Rubel Chakravarty Rakesh Shukla Ramu Ram Avesh Kumar Tyagi Ashutosh Dash Meera Venkatesh 《Chromatographia》2010,72(9-10):875-884
The feasibility of using tetragonal nano-zirconia (t-ZrO2) as an effective sorbent for developing a 99Mo/99mTc chromatographic generator was demonstrated. The structural characteristics of the sorbent matrix were investigated by different analytical techniques such as XRD, BET surface area analysis, FT-IR, TEM etc. The material synthesized was nanocrystalline, in tetragonal phase with an average particle size of ~7 nm and a large surface area of 340 m2 g?1. The equilibrium sorption capacity of t-ZrO2 is >250 mg Mo g?1. The present study indicates that 99Mo is both strongly and selectively retained by t-ZrO2 at acidic pH and 99mTc could be readily eluted from it, using 0.9% NaCl solution. A 9.25 GBq (250 mCi) t-ZrO2 based chromatographic 99Mo/99mTc generator was developed and its performance was repeatedly evaluated for 10 days. 99mTc could be eluted with >85% yield having acceptable radionuclidic, radiochemical and chemical purity for clinical applications. The compatibility of the product in the preparation of 99mTc labeled formulations such as 99mTc-EC and 99mTc-DMSA was evaluated and found to be satisfactory. 相似文献
58.
An efficient one-pot synthesis of polyhydroquinolines by four-component coupling reactions of aldehydes, ethyl acetoacetate, dimedone and ammonium acetate in the presence of HY-zeolite at ambient temperature has been achieved. The conversions took shorter times to form the products in excellent yields. HY-zeolite can be recovered and reused. 相似文献
59.
Ahmed Kamal R. Ramu Mohd. Ameruddin Azhar G.B. Ramesh Khanna 《Tetrahedron letters》2005,46(15):2675-2677
Copper(II) tetrafluoroborate catalyzes efficiently the selective opening of epoxides by amines leading to the synthesis of β-amino alcohols. The reaction works well with aromatic and aliphatic amines in high yields under solvent-free conditions. 相似文献
60.
Ring-opening of aziridines with potassium thiocyanate and thiols has efficiently been carried out at room temperature in the presence of sulfated zirconia to give the corresponding β-aminothiocyanates and β-aminosulfides, respectively, in high yields within 2 h and with high regioselectivity. The catalyst, a solid acid, functions under heterogeneous conditions. 相似文献