排序方式: 共有19条查询结果,搜索用时 187 毫秒
1.
Vijaya Bhaskar Reddy Ambavaram Venugopal Nandigam Madhavi Vemula Gangadhara Reddy Kalluru Madhavi Gajulapalle 《Biomedical chromatography : BMC》2013,27(7):916-923
A sensitive and selective liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for simultaneous determination of urapidil and aripiprazole in human plasma. A simple liquid–liquid extraction with ethyl acetate was used for the sample preparation. Chromatographic separation was achieved on a Phenomenex C18 (4.6 × 50 mm, 5 µm) column with 0.1% formic acid–acetonitrile (10:90, v/v) as the mobile phase with flow rate of 0.6 mL/min. The quantitation of the target compounds was determined in a positive ion multiple reaction monitoring mode. Calibration plots were linear over the range of 2.0–2503.95 ng/mL for urapidil and 1.0–500.19 ng/mL for aripiprazole. The lower limit of quantitation for urapidil and aripiprazole was 2.0 and 1.0 ng/mL, respectively. Mean recovery was in the range of 69.94–75.62% for both analytes and internal standards. Intra‐day and inter‐day precisions of the assay at three concentrations were 2.56–5.89% with accuracy of 92.31–97.83% for urapidil, and 3.14–6.84% with accuracy of 91.38–94.42% for aripiprazole. The method was successfully applied to human pharmacokinetic study of urapidil and aripiprazole in healthy human male volunteers. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
2.
Sivappa Rasapalli Gopalakrishna Jarugumilli Gangadhara Rao Yarrapothu Hamza Ijaz James A. Golen Paul G. Williard 《Tetrahedron letters》2014
The western segment of hygrocins A–B has been synthesized through the coupling of a chiral C5–C13 synthon with the sterically demanding hexasubstituted naphthalenic core. The C5–C13 chiral fragment has been assembled via a stereoselective Johnson orthoester rearrangement of an optically pure allylic alcohol derived from d-glucose. Our studies lay the platform for the determination of the absolute configuration of the unassigned C8-stereocenter of the title compounds in addition to the completion of the total synthesis of the unique ansamacrolides hygrocins A and B. 相似文献
3.
Structural Chemistry - In the present work, 2-substituted benzoxazole derivatives were synthesized from 2-(benzo[d]oxazol-2-yl) aniline. All the synthesized compounds were purified and... 相似文献
4.
Kishore Karumanchi Gangadhara Bhima Shankar Nangi Subba Reddy Danda Ramadas Chavakula Raghu Babu Korupolu Kishore Babu Bonige 《Journal of heterocyclic chemistry》2019,56(9):2683-2690
A facile, cost‐effective, and commercially viable synthesis of Raltegravir Potassium ( 1 ) has been developed from 2‐(1‐amino‐1‐methyl‐ethyl)‐N‐[(4‐fluorophenyl)methyl]‐1,6‐dihydro‐5‐hydroxy‐1‐methyl‐6‐oxo‐4‐pyrimidinecarboxamide ( 9 ) with high purity and in good yields. In addition, a new approach for the synthesis of key amine intermediate ( 9 ) of Raltegravir Potassium ( 1 ) from commercially available 2‐amino‐2‐methylpropanenitrile hydrochloride ( 2 ) is also described. The key features of the synthesis are fewer synthetic steps, employing the inexpensive reagents and eco‐friendly. 相似文献
5.
Gangadhara S. Ponrathnam C. Noel D. Reyx F. Kajzar 《Journal of polymer science. Part A, Polymer chemistry》1999,37(5):513-524
We report the synthesis of a nematic copolymer, P(CBMS‐co‐M3), prepared by free radical polymerization of an equimolecular mixture of p‐(4‐cyanobiphenyl‐4′‐yloxy)methylstyrene (CBMS) and N‐[3‐(4‐cyanobiphenyl‐4′‐yloxy)propyl]maleimide (M3) and two isotropic alternating copolymers, P(S‐alt‐Mn) (n = 3,6) prepared by chemical modification of poly(styrene‐alt‐maleimide), P(S‐alt‐M), by n‐(4‐cyanobiphenyl‐4′‐yloxy)alkan‐1‐ol. These copolymaleimides were characterized by NMR, DSC, and optical microscopy. Some corona poling experiments were performed and the second harmonic coefficients d31 and d33 were measured. It was shown that one can gain in net polar ordering by starting with a liquid crystalline system. The ratio d33/d31 was much larger than 3, in agreement with the molecular statistical models for electric field poling of liquid crystals. At ambient conditions, changes of d33 and d31 are 15% over 325 days. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 513–524, 1999 相似文献
6.
7.
Gangadhara C. Noel M. Thomas D. Reyx 《Journal of polymer science. Part A, Polymer chemistry》1998,36(14):2531-2546
A new homologous series of SCLCPs containing the 4-cyanobiphenyl mesogenic group attached to the polymaleimide backbone through paraffinic spacers of two to eight methylene units have been prepared. All the polymers exhibit liquid crystalline behavior; specifically SAd- (or SC-) like and nematic phases are observed. The glass transition temperature decreases from 150 to 43°C on increasing spacer length. The isotropization temperatures exhibit an odd–even effect on varying the length and parity of the spacer, in which the odd members exhibit the higher values. This is attributed to the change in the average shape of the side chain as the parity of spacer is varied. The isotropization temperatures (>300–120°C) and the mesophase thermal stabilities (190–60°C) are high. Comparison is made with polymers containing the same mesogenic group attached to backbones of decreasing rigidity. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2531–2546, 1998 相似文献
8.
Catalytic decomposition of CH4 over Ni-Al2O3-SiO2 catalysts: Influence of pretreatment conditions for the production of H2 下载免费PDF全文
Jangam Ashok Gangadhara Raju Padigapati Shiva Reddy Machiraju Subrahmanyam Akula Venugopal 《天然气化学杂志》2008,17(2):113-119
This article reports the production of COx free hydrogen and carbon nanofibers by the catalytic decomposition of methane over Ni-Al2O3-SiO2 catalysts. The influence of reaction temperature, pretreatment temperature, and effect of reductive pretreatment on the decomposition of methane activity is investigated. The physico-chemical characteristics of fresh and deactivated samples were characterized using BET-SA, XRD, TPR, SEM/TEM, CHNS analyses and correlated with the methane decomposition results obtained. The Ni-Al-Si (4 : 0.5 : 1.5) catalyst reduced with hydrazine hydrate produced better H2 yields of ca. 1815 mol H2/mol Ni than the catalyst reduced with 5% H2/N2. 相似文献
9.
Akula Raghunadh Suresh Babu Meruva Ramamohan Mekala K. Raghavendra Rao Thalishetti Krishna R. Gangadhara Chary L. Vaikunta Rao U.K. Syam Kumar 《Tetrahedron letters》2014
An efficient synthesis of unsymmetrically substituted 1,3-pyrazole derivatives has been developed via three-component coupling reaction involving 3-(dimethylamino)-1-phenylprop-2-en-1-one, hydrazine, and aryl halides in one pot process exhibiting high regioselectivity. The pyrazole synthesis proceeds via a sequential series of reactions such as Michael addition, heterocyclization, dehydration, and Ullmann cross-coupling. 相似文献
10.
We present a relativistic model for the centrifugal acceleration of plasma bunches and the coherent radio emission in pulsar
magnetosphere. We find that rotation broadens the width of leading component compared to the width of trailing component.
We explain this difference in the component widths using the nested cone emission geometry. We estimate the effect of pulsar
spin on the Stokes parameters, and find that the inclination between the rotation and magnetic axes can introduce an asymmetry
in the circular polarization of the conal components. We analyse the single pulse polarization data of PSR B032954 at 606
MHz, and find that in its conal components, one sense of circular polarization dominates in the leading component while the
other sense dominates in the trailing component. Our simulation shows that changing the sign of the impact parameter changes
the sense of circular polarization as well as the swing of polarization angle
Article presented at the International Conference on the Frontiers of Plasma Physics and Technology, 9–14 December 2002, Bangalore,
India. 相似文献