Spectroscopic Investigation of Tungsten Ions in Lead Scandium Phosphate Glass System

Lead scandium phosphate glasses (PbO-Sc₂O₃-P₂O₅) containing different concentrations of tungsten oxide (WO₃) ranging from 0 to 5 mol% were prepared. A number of studies, viz. differential thermal analysis (DTA), infrared spectra, optical absorption, and electron spin resonance (ESR) spectra, have been carried out. The results of DTA indicated the highest glass forming ability for the glass containing 5 mol% of WO₃. The results of spectroscopic studies have been analyzed in light of different oxidation states of tungsten ions.     

Enantiospecific first total synthesis of 7a(S)-p-hydroxyphenopyrrozin

An enantiospecific first total synthesis of metabolite 7a(S)-p-hydroxyphenopyrrozin 2, isolated from the cultured fungi Chromocleista sp. has been achieved starting from readily and abundantly available l-proline. The strategy of synthesis utilizes base mediated cyclization and base mediated oxygenation as the key steps.     

Self Organization and Redox Behavior of Poly(vinylferrocene)-block-Poly(isobutylene)-block-Poly(vinylferrocene) Triblock Copolymer †

Self organization and redox behavior of a ferrocene containing triblock copolymer, poly(vinylferrocene)-block-poly(isobutylene)-block-poly(vinylferrocene), with narrow molecular weight distribution in solutions and in thin films were investigated. Dynamic light scattering studies of the block copolymer in dilute solutions indicated that the polymer chains aggregated at relatively low concentrations. The aggregations of polymer chains were observed in toluene, as well as in tetrahydrofuran at concentrations as low as 0.014 mg/mL and 0.0045 mg/mL, respectively. Thin films of the copolymer showed reversible single electron redox behavior, similar to that of ferrocene. Morphology and micro-phase separation of the copolymer was analyzed by transmission electron microscopy.     

Feasibility of Polyvinyl Alcohol as a Transdermal Drug Delivery System for Terbutaline Sulphate

A series of terbutaline sulphate drug incorporated polyvinyl alcohol (PVA) matrix films were produced by the solvent evaporation method. The effect of xanthan gum and plasticizers (propylene glycol and dibutyl phthalate) on the rate and amount of drug diffusion from PVA membrane across the hydrated cellophane membrane has been evaluated, using an open glass diffusion‐tube. The obtained films were clear, smooth and flexible having sufficient mechanical strength. The mechanical performance of the dry PVA films with xanthan gum and plasticizers were also ascertained. Polyvinyl alcohol‐xanthan gum blends showed a high rate of drug release compared to that of polyvinyl alcohol film alone. Among the two plasticizers employed, propylene glycol showed better permeability. Among different formulations studied, the formulation PVA/xanthan gum/propylene glycol (F7) was found to be an optimized composition for efficient transdermal delivery of the model drug, terbutaline sulphate. The mechanism of drug diffusion has been evaluated using the Peppas model. Stability studies carried out on polymer‐drug formulations revealed that the drug is stable at 40°C and 75% RH for a period of 6 weeks.     

Synthesis,spectroscopic and crystal structure analysis of 2-(4-fluorobenzyl)-6-(4-methoxyphenyl)imidazo[2,1-b][1,3,4]thiadiazole and its morpholinomethyl derivative

The preparation of 2-(4-fluorobenzyl)-6-(4-methoxyphenyl)-5-morpholin-1-ylmethyl imidazo[2,1-b][1,3,4]thiadiazole via the intermediate 2-(4-fluorobenzyl)-6-(4-methoxyphenyl)Imidazo[2,1-b][1,3,4] thiadiazole is described. Elemental analysis, IR spectrum, ¹H NMR and X-ray crystal structure analyses were carried out to determine the compositions and molecular structures of the two compounds. The crystal packing exhibits intermolecular C–H?O, C–H?N, C–H?F and π–π stacking interactions leading to the formation of the supramolecular network.     

Computational studies on the structures and energies of the tautomers of 1-amino-3-nitrotriazol-5-one-2-oxide

Molecular orbital calculations at the DFT-B3LYP/aug-cc-pVDZ level were performed for the possible tautomers of 1-amino-3-nitro-1,2,4-triazol-5-one-2-oxide. We have examined the substitution effects of amino and nitro groups by comparing calculated geometries, relative energies, and electrostatic potentials of model molecules. The optimized structures, vibrational frequencies, and thermodynamic values for triazol-5-one-N-oxides were obtained in their ground state. The results show 1H, 4H tautomers to be most stable. Detonation velocity and detonation pressure were evaluated by the Kamlet and Jacob equations based on the predicted density and the calculated heat of explosion. Explosive properties appear to be promising compared with those of 1,3,5-trinitro-1,3,5-triazine (D = 8.75 km/s, P = 34.7 Gpa) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (D = 8.96 km/s, P = 35.96 Gpa), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (D = 9.20 km/s, P = 42.0 Gpa) and octanitrocubane (D = 9.90 km/s, P = 48.45 GPa). The designed triazol-5-one-N-oxides satisfy the criteria of high energy density materials.     

Speciation of 30 % tri-n-butyl phosphate solvent during extraction of nitric acid

Several solutions of 30 % TBP/n-dodecane were equilibrated with different concentrations of aqueous nitric acid solutions at 298.15 K at a phase ratio of unity. The resultant equilibrated aqueous and organic solutions were analyzed for acidity. A three-solvate model with molecular HNO₃ based mechanism was assumed for nitric acid extraction by TBP. With nonlinear chemometric methods, the coefficients were evaluated. With the set of optimized coefficients, derived on the basis of experiments reported in this work, the estimated solvate species and free-TBP species in the TBP containing organic phase were found to be in good agreement with the reported concentrations in the literature.     

Head group specificity of novel functionalized surfactants: synthesis,self-assembly and calcium tolerance

The present work describes the synthesis, characterization and application of functionalized surfactants derived through simple organic reaction steps. These surfactants have been particularly tailor made to resist hardness due to calcium ions in water. It is unique of its kind because here the surfactants have an analogous hydrophobic chain but differ structurally in the composition of the head groups in terms of the position of attachment of the chain. The effect of this small variability in the head group on the surfactant property, adsorption, self assembly and calcium tolerance behaviour has been studied in detail. This kind of phenol–keto surfactants has not been reported before. It was also found that one of the surfactants was more tolerant towards Ca²⁺ ion than the other. The individual packing behaviour of the surfactants at the air–water interface has been projected to cause this difference which is very interesting.     

BMIM[BF4]: An Efficient Ionic Liquid Medium for the Synthesis of Chromeno[b]pyridines as Potential Anticancer Agents

Russian Journal of Organic Chemistry - A series of 2-amino-4-aryl-5-oxochromeno[4,3-b]pyridine-3-carbonitriles have been synthesized with good yields (85–90%) by reacting...