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581.
Goyal C. P. Goyal D. Ganesh V. Ramgir N. S. Navaneethan M. Hayakawa Y. Muthamizhchelvan C. Ikeda H. Ponnusamy S. 《Physics of the Solid State》2020,62(10):1796-1802
Physics of the Solid State - Degradation of organic pollutants got more attention for detoxification of water. In this paper, pure and Zn-doped Cu2O particles were successfully synthesized by water... 相似文献
582.
Two tetrapeptide derivatives [peptide A (Boc–Ala–Ile–Ile–Gly–OMe) and peptide B (Boc–Ala–Ile–Leu–Ser–OMe)], that take helical turn conformation in solution, were shown to form monolayer at the air/water interface. Circular dichroism (CD) measurements indicate that peptide A has more helical turn propensity than peptide B in sodium dodecyl sulphate (SDS) micelles. Langmuir–Blodgget film study of peptides A and B suggest that both the peptides form stable monolayer at the air/water interface. Spectroscopic investigations reveal that peptide A forms helical turn assemblage on transferring the film into hydrophilic quartz and hydrophobic ZnSe surfaces. Whereas, peptide B adopts β-sheet structure on hydrophilic surface and a mixture of β-sheet and helical turn conformation on hydrophobic surface. 相似文献
583.
Kamble GS Kolekar SS Anuse MA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(5):1455-1466
A simple and selective spectrophotometric method was developed for the determination of copper(II) with 1-(2',4'-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol [2',4'-dinitro APTPT] as a chromogenic reagent. The procedure was based on the synergistic extraction of copper(II) with 2',4'-dinitro APTPT in the presence of 0.5 mol L(-1) pyridine to give green colored ternary complex of a molar ratio 1:2:2 (M:L:Py) in the pH range 8.7-10.5. It exhibits a maximum absorption of colored complex at 445 nm and 645 nm in chloroform against the reagent blank. Beer's law was followed in the concentration range 10-80 μg mL(-1) of copper(II) and optimum range of 20-70 μg mL(-1) the metal as evaluated from Ringbom's plot. The molar absorptivity and Sandell's sensitivity of copper(II)-2',4'-dinitro APTPT-pyridine complex in chloroform are 0.87×10(3) L mol(-1)c m(-1) and 0.072 μg cm(-2), respectively. The interfering effects of various cations and anions were also studied, and use of suitable masking agents enhances the selectivity of the method. The proposed method is rapid, reproducible and successfully applied for the determination of copper(II) in binary and synthetic mixtures, alloys, pharmaceutical formulations, environmental and fertilizer samples. Comparison of the results with those obtained using an atomic absorption spectrophotometer also tested the validity of the method. 相似文献
584.
Vaidya Vikas V. Menon Sasikumar N. Singh Ganesh R. Kekare Maharudra B. Choukekar Milind P. 《平面色谱法杂志一现代薄层色谱法》2007,20(2):145-147
JPC – Journal of Planar Chromatography – Modern TLC - An HPTLC method for simultaneous determination of clotrimazole and tinidazole in a pharmaceutical formulation has been developed... 相似文献
585.
A short, versatile, and enantioselective synthesis of 1-deoxy-8-epi-castanospermine (5), 1-deoxy-8-hydroxymethyl castanospermine (6), and (6S,7S,8R,8aR)-8-amino-octahydroindolizine-6,7-diol (7) is achieved from a common template 12. The key step utilized is PET provoked amine radical cyclization of 11 to 12 in excellent diastereoselectivity. The exocyclic double bond at C-8 of the template is functionalized to obtain 5-7 as exclusive diastereomers. 1-Deoxy-8-epi-castanospermine exhibited inhibition of α- and β-galactosidase and β-glucosidase. Compounds 6 and 7 were found to be weak inhibitors of β-glucosidase. 相似文献
586.
Spyros P. Nikas Ganesh A. Thakur Shakiru O. Alapafuja Alexandros Makriyannis 《Tetrahedron》2007,63(34):8112-8123
The availability of tetrahydrocannabinols (Δ9-THC), tetrahydrocannabivarins (Δ9-THCV), and their metabolites in both their undeuterated and deuterated forms is critical for the analysis of biological and toxicological samples. We report here a concise methodology for the syntheses of (−)-Δ9-THC and (−)-Δ9-THCV metabolites in significantly improved overall yields using commercially available starting materials. Our approach allowed us to obtain the key intermediates (6aR,10aR)-9-nor-9-oxo-hexahydrocannabinols in four steps from (+)-(1R)-nopinone. This was followed by an optimized Shapiro reaction to give the (−)-11-nor-9-carboxy-metabolites, which were converted to their respective (−)-11-hydroxy analogs. The synthetic sequence involves a minimum number of steps, avoids undesirable oxidative conditions, and incorporates the costly deuterated resorcinols near the end of the synthetic sequence. This methodology enabled us to synthesize eight regiospecifically deuterated (−)-Δ9-THC and (−)-Δ9-THCV metabolites in a preparative scale and high optical purity without deuterium scrambling or loss. 相似文献
587.
Ganesh V Pal SK Kumar S Lakshminarayanan V 《Journal of colloid and interface science》2006,296(1):195-203
Self-assembled monolayers (SAMs) of liquid crystalline thiol-terminated alkoxycyanobiphenyl molecules with different alkyl chain lengths on Au surface have been studied for the first time using electrochemical techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The barrier property of the SAM-modified surfaces was evaluated using two different redox probes, namely potassium ferro/ferri cyanide and hexaammineruthenium(III) chloride. It was found that for short-length alkyl chain thiol (C5) the electron transfer reaction of hexaammineruthenium(III) chloride takes place through tunneling mechanism. In contrast, redox reaction of potassium ferro/ferri cyanide is almost completely blocked by the SAM-modified Au surface. From the impedance data, a surface coverage value of >99.9% was calculated for all the thiol molecules. 相似文献
588.
Aza‐Quaternary Scaffolds from Selective Bond Cleavage of Bridgehead‐Substituted 7‐Azabicyclo[2.2.1]heptane: Total Synthesis of (+)‐Cylindricines C–E and (−)‐Lepadiformine A 下载免费PDF全文
Prof. Dr. Ganesh Pandey Vaitla Janakiram 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(37):13120-13126
A novel bridgehead‐substituted aza‐bicyclic framework has been designed and developed in both enantiomeric forms through an asymmetric desymmetrization reaction. Strategic exploitation of the ring strain in the aza‐bicyclic framework has been utilized for the construction of the chiral aza‐quaterenary scaffolds by selective bond fragmentation processes. Furthermore, a strategically designed precursor is employed for selective bond cleavage to initiate a cascade rearrangement for the total synthesis of the 1‐azaspirotricyclic marine alkaloids (+)‐cylindricines C, D, and E, as well as (?)‐lepadiformine A. An oxidation/retro‐aldol/aza‐Michael sequence generated three new chiral centers with the required configuration in one pot. 相似文献
589.
[structures: see text] A serious drawback of peptide nucleic acids (PNAs) from an application perspective that has not been adequately dealt with is nondiscrimination of identical DNA and RNA sequences. An analysis of the available X-ray and NMR solution structures of PNA complexes with DNA and RNA suggested that it might be possible to rationally impart DNA/RNA duplex binding selectivity by tuning the dihedral angle beta of the flexible ethylenediamine part of the PNA backbone (II) via suitable chemical modifications. Cyclohexanyl PNAs (chPNAs) with beta approximately = 65 degrees were designed on the basis of this rationale. The chPNAs introduced remarkable differences in duplex stabilities among their DNA and RNA complexes, with melting temperatures (deltaTm(RNA-DNA) = +16-50 degrees C) depending on the number of modifications and the stereochemistry. This is a highly significant, exceptional binding selectivity of a mix sequence of PNA to RNA over the same DNA sequence as that seen to date. In contrast, cyclopentanyl PNAs (cpPNAs) with beta approximately = 25 degrees hybridize to DNA/RNA strongly without discrimination because of the ring puckering of the cyclopentane ring. The high affinity of chPNAs to bind to RNA without losing base specificity will have immediate implications in designing improved PNAs for therapeutic and diagnostic applications. 相似文献
590.
Akshay Ganesh Iyer Jeroen Adrianus van Oijen Johannes Hendrikas Maria ten Thije Boonkkamp Laurentius Phlippus Hendrika de Goey 《Combustion Theory and Modelling》2016,20(1):173-188
The mass-based stretch rate is used to study the response of premixed axisymmetric counterflow flames subject to an oscillating strain rate. Integral analysis is used to estimate the mass burning rate of the oscillating counterflow flames. From this study it can be concluded that the flame responds in a nonlinear manner. With an increase of the applied strain frequencies, it is found that unsteady stretch effects arising due to flame thickness variations become significant and the mass-based stretch rate is able to capture these nonlinear effects. The inclusion of these unsteady stretch effects in the mass-based stretch helps the integral analysis to predict the mass-burning rate of oscillating flames more accurately. 相似文献