Stereoselective synthesis of tarchonanthuslactone via the Prins cyclisation

The stereoselective total synthesis of tarchonanthuslactone, a polyketide natural product, has been achieved. The synthesis exploits the high stereochemical control in the Prins cyclisation along with ring closing metathesis (RCM) as a key step.     

Three new ingol diterpenes from Euphorbia nivulia: evaluation of cytotoxic activity

The latex of Euphorbia nivulia afforded three new ingol diterpenes, 3-acetyl-8-methoxyl-7-angolyl-12-hydroxylingol (7), 3,12-diacetyl-7-hydroxy-8-methoxylingol (8), and 3,12-diacetyl-7-angolyl-8-hydroxylingol (9) along with five known ingol diterpenes 2-6 and a known triterpene cyclonivulinol (1). Their structures were established by means of spectroscopic analysis. Diterpenes 2-9 were evaluated for their cytotoxic activity.     

Effect of RuO2 in the shape selectivity of submicron-sized SnO2 structures

Several dissimilar types of tin oxide microstructures including bipyramids, cubes, and wires synthesized effectively by means of a simple approach were investigated using X-ray diffraction (XRD), thermogravimetry/differential thermometric analysis (TG-DTA), and X-ray photoelectron spectroscopy (XPS). A possible growth mechanism is proposed using the results of these studies. The texture coefficient values of all the structures, indexed to a tetragonal lattice, exhibit amazing variation in the preferred orientation with respect to their shapes. Although XPS data indicate that wires and cubes have a strong SnO(2) type signal, bipyramids interestingly exhibit both SnO and SnO(2) signals and a correlation of the binding energy helps in understanding the growth kinetics of such submicron structures. The results suggest that the bipyramids are formed because of the vapor-solid process (VS) while wires and cubes are formed by the vapor-liquid-solid (VLS) progression.     

Copper-ion-induced photoluminescence tuning in CdSe nanoparticles

Investigations have been made on luminescence properties of copper-doped CdSe nanoparticles, synthesized via green chemical route. The nanoparticles remain stable under normal atmospheric conditions and can be redispersed in suitable solvents (water and dimethyl formamide). The photoluminescence peak positions in the copper doped CdSe nanoparticles are found to strongly depend on the copper ion concentration. Under UV irradiation visible luminescence covering the entire visible range has been observed.     

A short note on weighted mean matrices

In the present paper we have established a relation between (N, p _n ) and (N, q _n ) weighted mean matrices, when considered as bounded operators on 1^p, 1 < p < ∞.     

Hydrogen Evolution from Glucose with the Combination of Glucose Dehydrogenase, Ferredoxin NADP Reductase and Hydrogenase from A. Eutrophus H16

Hydrogen evolution system from glucose consisting of glucose dehydrogenase from Bacillus sp., ferredoxin NADP reductase from spinach leaves and hydrogenase from Alcaligenes eutrophus H16 was established. When the solution containing glucose, glucose dehydrogenase, NAD, ferredoxin NADP reductase, methyl viologen and hydrogenase was incubated at 30°C, hydrogen evolution was observed.     

Investigating the thermal properties of polyethylene plasma modified by using unconventional chemical vapors

In this work, we presented plasma modification of low-density polyethylene (PE) powder using unconventional chemicals. This work focused on the thermal behavior of modified PE. Plasma modification of PE was carried out using unconventional chemical vapor i.e., acetone, toluene, ethanol, methanol, isopropanol, and chloroform, respectively. For all the process, the modification time was kept constant for 2 min. Chamber pressure of 100 Pa was used for the study. The thermal behavior of the plasma-modified and unmodified PE was carried out by differential scanning calorimetry and thermogravimetric analysis. We have found that there is a maximum improvement of crystallinity and thermal stability of PE when ethanol is used for plasma modification. Results obtained from DSC showed that plasma modification of PE in ethanol vapors increases the crystallinity of the PE without damaging the surface properties. Thermal stability of PE plasma modified in ethanol gives maximum thermal improvement to almost 25 °C at 5 mass% mass loss compared to unmodified PE.     

Chitosan-SO3H: an efficient,biodegradable, and recyclable solid acid for the synthesis of quinoline derivatives via Friedländer annulation

Chitosan-SO₃H is found to catalyze the Friedländer condensation/annulation reaction of 2-aminoaryl ketones with α-methyleneketones to produce the corresponding quinoline derivatives in high yields in short reaction times. The use of recyclable and biodegradable chitosan-SO₃H makes this method quite simple, more convenient, and economically viable compared to acid catalyzed methods reported in the literature.