CTAB promoted CuI catalyzed green and economical synthesis of 1,4-disubstituted-1,2,3-triazoles

A practical, straightforward, and highly efficient CuI mediated green protocol for the regioselective synthesis of 1,4-disubstituted-1,2,3-triazole was developed using cetyltrimethylammonium bromide as a cheap additive in good to excellent yields. Low catalyst loadings, environmentally friendly solvent, wide substrate scope and short reaction times at room temperature make this strategy more accessible and safe.     

An Efficient Method for the Synthesis of 10‐Aminoartemisinin Derivative

An efficient method for the synthesis of 10‐aminoartemisinin derivative has been developed from 10‐acetoxyartemisinin and acetonitrile catalyzed by trimethylsilyltrifluoromethanesulfonate in good yield.     

New gas chromatographic method for residue determination of dithiopyr in soil, wheat grain and straw

A gas chromatographic method has been developed for a new pyridine herbicide, dithiopyr, utilising an electron capture detector. The method makes use of a column (10 m x 0.534 mm I.D.; 1 microm film thickness) containing HP-1 with nitrogen as a carrier gas at a flow rate of 15 ml min(-1) at temperatures of 190, 210, 270 degrees C for oven, injector port and detector, respectively. Soil, wheat grain and straw samples fortified with dithiopyr were extracted with acetone-0.2 M HCl (95:5) and cleaned up by partitioning with hexane. The technique has a sensitivity of 0.05 microg ml(-1) and the recovery of dithiopyr from soil, wheat grain and straw ranged between 80 and 99%.     

Electron impact mass spectra of meliacins

The electron impact mass spectra of some new meliacins and their derivatives are discussed. The major fragmentation modes include the functional group losses, the different ring cleavages and the loss of the furan residue as neutral fragments. A mechanism for the loss of the furan moiety from the molecular ion is discussed in detail with the help of deuterium labelling, high resolution and metastable data.     

A comparative study on the effects of salt and filler on transport and structural properties of organic–inorganic hybrid electrolytes

Organic–inorganic hybrid electrolytes based on the reaction of tri-block copolymer poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether), poly(ethylene glycol diglycidyl ether, and (3-glycidyloxypropyl)trimethoxysilane doped with LiClO₄ and SiO₂ nanoparticles were synthesized by a sol–gel process. The structural and dynamic properties of the materials thus obtained were systematically investigated by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, alternate current impedance, and ¹³C solid-state NMR measurements. A maximum ionic conductivity of 3.2?×?10^?5 S cm^?1 was obtained at 30 °C for the solid hybrid electrolyte with a [O]/[Li] ratio of 16 and 7 wt% of SiO₂ nanoparticles. A Vogel–Tamman–Fulcher-like temperature dependence of ionic conductivity was observed for the hybrid electrolytes, implying that the diffusion of charge carriers was assisted by the segmental motions of the polymer chains.     

Effect of Association of Curcumin with Chitosan in Presence of TX 100 on Its Degradation

The binding of curcumin with chitosan in the presence of nonionic surfactant, iso-octylphenoxy-polyethoxy-ethanol (Triton X-100) and its stability in such systems have been investigated by monitoring the changes in the absorption spectra at physiological pH (7.4). It was observed that curcumin binds to chitosan more than 10 times stronger in presence of TX 100 at the experimental condition. From spectrophotometric analysis of the kinetics of degradation of the dye, it was observed that the yield of suppression of degradation of curcumin by chitosan increases by 33.5% in the presence of TX 100 than alone. The interaction of the dye with chitosan has been found to be exothermic and driven by hydrophobic interactions, hydrogen bond formation, and electrostatic interactions.     

Dinitroaliphatics as linkers: application in the synthesis of novel artemisinin carba-dimer

Abstract  

The versatility of nitroaliphatics is demonstrated by using it in the syntheses of artemisinin derived dimers. A few novel artemisinin derived dimer and monomer have been synthesized using nitroalkane as linker.     

Plasma-Maser Instability of Bernstein Mode in Presence of Magnetohydrodynamic Turbulence

A theoretical study is made on the amplification mechanism of electrostatic Bernstein mode wave in presence of kinetic Alfven wave turbulence in a magnetized plasma on the basis of plasma-maser interaction. It is shown that a test high frequency electrostativ Bernstein mode wave is unstable in the presence of low frequency kinetic Alfven wave turbulence. The growth rate of the Bernstein wave vanishes only in an unmagnetized plasma. Because of the universal existence of the kinetic Alfven waves in large scale plasmas, the results have potential importance in space and astrophysical radiation processes.     

The evolution of the resonant mode in plasma-maser interaction

We study the evolution of the resonant waves considering its interaction with the nonresonant waves and the plasma particles due to plasma-maser effect. The nonlinear dielectric function of the resonant wave is calculated and is found to consist of two parts: the direct and the polarization coupling terms. On the other hand, the nonlinear dielectric function of the nonresonant wave consists only of the direct coupling term. The significance of our results is discussed.