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Aggarwal R.,Kurukshetra University | Sumran G.,Kurukshetra University | Sumran G.,Technology Education and Research Integrated Institutions | Kumar V.,Kurukshetra University | Mittal A.,Kurukshetra University
European Journal of Medicinal Chemistry | Year: 2011

A new class of photonucleases, 1-aryl/heteroaryl-4-substituted-1,2,4- triazolo[4,3-a]quinoxalines (4) was synthesized in a facile and efficient manner via copper(II) chloride mediated oxidative intramolecular cyclization of 2-(arylidenehydrazino)-3-substituted-quinoxalines (3). DNA cleavage potency of compounds 4a-d (40 μg each) was quantitatively evaluated on supercoiled plasmid ΦX174 under UV irradiation (312 nm, 15 W) without any additive. Compound 4c was found to be the most efficient DNA photocleaver which had converted supercoiled DNA (form I) into the relaxed DNA (form II) at 30 μg and the DNA photocleavage activity increases with increase in concentration of 4c. © 2011 Elsevier Masson SAS. All rights reserved.


Aggarwal R.,Kurukshetra University | Sumran G.,Kurukshetra University | Sumran G.,Technology Education and Research Integrated Institutions | Garg N.,Kurukshetra University | Aggarwal A.,Kurukshetra University
European Journal of Medicinal Chemistry | Year: 2011

An efficient and environmental benign regioselective synthesis of some new pyrazol-1′-ylpyrazolo[1,5-a]pyrimidines (7b-h) has been accomplished via treatment of 3(5)-amino-5(3)-hydrazinopyrazole dihydrochloride (5) with several unsymmetrical 1,3-diketones (6b-h) using water as a solvent without any catalysts or additives. The structure of 7b-h was established on the basis of rigorous analysis of 1H, 13C NMR, IR spectral data and MS. Eight compounds (7a-h) were screened for their antibacterial activity against two gram-positive and two gram-negative bacteria and compounds (7a, b, d and e) for antifungal activity against four phytopathogenic fungi. Compounds 7c and 7e manifest rather broad antibacterial activity than standard antibiotics. One lead compound, 7a (10 mg/ml and 200 mg/ml) exhibited equipotent or more potent antifungal activity against all tested microorganisms than standard drug. © 2011 Elsevier Masson SAS. All rights reserved.


Chauhan R.,Technology Education and Research Integrated Institutions | Kumar A.,National Institute of Technology Kurukshetra | Chaudhary R.P.,Sant Longowal Institute of Engineering And Technology
Asian Journal of Chemistry | Year: 2012

Nanocrystals of undoped and zinc doped cadmium sulphide (Cd1-xZnx S, where x = 0.00 to 0.10) were synthesized by chemical precipitation method. Structural characterization of as synthesized semiconductor nanoparticles was performed by X-ray diffraction pattern while optical characterization were done by UV-Visible absorption spectroscopy. XRD pattern showed that the synthesized Zn doped CdS nanoparticles have wurtzite hexagonal structure with 3-39 nm average crystallite size. Optical absorption measurements indicated red shift in the absorption band edge upon Zn doping. Direct allowed band gap of undoped and Zn-doped CdS nanoparticles measured by UV-Visible spectrophotometer were 2.4 to 2.2 eV at 500 °C.


Chauhan R.,Sant Longowal Institute of Engineering And Technology | Chauhan R.,Technology Education and Research Integrated Institutions | Kumar A.,National Institute of Technology Kurukshetra | Chaudhary R.P.,Sant Longowal Institute of Engineering And Technology
Research on Chemical Intermediates | Year: 2012

Undoped and silver-doped TiO 2 nanoparticles (Ti 1-xAg xO 2, where x = 0.00-0.10) were synthesized by a sol-gel method. The synthesized products were characterized by X-ray diffraction (XRD), particle size analyzer (PSA), scanning electron microscope (SEM), and UV-Visible spectrophotometer. XRD pattern confirmed the tetragonal structure of synthesized samples. Average crystallite size of synthesized nanoparticles was determined from X-ray line broadening using the Debye-Scherrer formula. The crystallite size was varied from 8 to 33 nm as the calcination temperature was increased from 300 to 800 °C. The incorporation of 3 to 5% Ag + in place of Ti 4+ provoked a decrease in the size of nanocrystals as compared to undoped TiO 2. The SEM micrographs revealed the agglomerated spherical-like morphology of particles. SEM, PSA, and XRD measurements show that the particles size of the powder is in nanoscale. Optical absorption measurements indicated a red shift in the absorption band edge upon silver doping. Direct allowed band gap of undoped and Ag-doped TiO 2 nanoparticles measured by UV-Vis spectrometer were 3.00 and 2.80 eV, respectively, at 500 °C. © Springer Science+Business Media B.V. 2012.


Chauhan R.,Sant Longowal Institute of Engineering And Technology | Chauhan R.,Technology Education and Research Integrated Institutions | Kumar A.,National Institute of Technology Kurukshetra | Chaudhary R.P.,Sant Longowal Institute of Engineering And Technology
Research on Chemical Intermediates | Year: 2012

Nanocrystals of undoped and nickel-doped zinc oxide (Zn 1-xNi xO, where x = 0.00-0.05) were synthesized by the coprecipitation method. Crystalline size, morphology, and optical absorption of prepared samples were determined by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and UV-visible spectrometer. XRD and SEM studies revealed that Ni-doped ZnO crystallized in hexagonal wurtzite structure. Doping of ZnO with Ni 2+ was intended to enhance the surface defects of ZnO. The incorporation of Ni 2+ in place of Zn 2+ provoked an increase in the size of nanocrystals as compared to undoped ZnO. Crystalline size of nanocrystals varied from 10 to 40 nm as the calcination temperature increased. Enhancement in the optical absorption of Ni-doped ZnO indicated that it can be used as an efficient photocatalyst under visible light irradiation. Optical absorption measurements indicated a red shift in the absorption band edge upon Ni doping. The band gap value of prepared undoped and Ni-doped ZnO nanoparticles decreased as annealing temperature was increased up to 800 °C. © Springer Science+Business Media B.V. 2012.

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