Immobilization of copper ions onto α‐amidotriazole‐functionalized magnetic nanoparticles and their application in the synthesis of triazole derivatives in water

A new heterogeneous copper catalyst was synthesized by immobilization of copper ions onto magnetic nanoparticles with a new ligand based on triazole. The catalyst was characterized using scanning and transmission electron microscopies, atomic absorption and Fourier transform infrared spectroscopies, and thermogravimetric, elemental and energy‐dispersive X‐ray analyses. The results confirmed that a good level of organic groups was immobilized on the magnetic nanoparticles. Huisgen cycloaddition reaction was chosen as a model reaction for the investigation of catalyst activity under green conditions. Phenylacetylene and benzyl bromide derivatives were used for the synthesis of triazoles. The reaction proceeded with good to excellent yields for various alkynes and alkyl halides. To investigate catalyst activity for inactive alkynes, aliphatic alkynes were used in the model reaction. The corresponding triazoles were obtained in good to excellent yields and a high regioselectivity for products was obtained. The catalyst was easily separated using an external magnetic field and subsequently reused in ten reaction cycles without any loss of catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd.     

Changes in the natural abundance of 13CO2/12CO2 in breath due to lipopolysacchride‐induced acute phase response

The natural abundance of carbon‐13 in blood proteins increases during the cachectic state and may be a biomarker for disease status. We hypothesized a corresponding drop in the relative abundance of ¹³C in breath CO₂. Using the lipopolysacchride (LPS)‐induced endotoxemia model of the acute cachectic state, we demonstrated that the acute phase response causes shifts in the stable isotopes of carbon in exhaled CO₂ (¹³CO₂/¹²CO₂ delta value) shortly after administration of LPS while glucocorticoid treatment does not. Mice were injected with LPS and stable isotopes of blood amino acids and carbon in exhaled CO₂ were monitored. An increase in the relative isotopic mass of serum alanine, proline and threonine was observed at 3 h after LPS injection. Breath delta values began dropping immediately after administration of LPS, and were 4–5 delta values lower than those of the control animals by 2.5 h after injection. A corresponding drop in delta value was not observed with dexamethasone treatment. Thus protein synthesis during the acute phase response probably caused the fractionation of stable isotopes observed in the plasma amino acids and in exhaled breath ¹³CO₂ delta values. The exhaled breath ¹³CO₂ delta value may be a valuable real‐time biomarker of cachexia associated with an acute phase response due to endotoxemia. Copyright © 2009 John Wiley & Sons, Ltd.     

A novel microextraction technique based on 1-hexylpyridinium hexafluorophosphate ionic liquid for the preconcentration of zinc in water and milk samples

A simple dispersive liquid-liquid microextraction methodology based on the application of 1-hexylpyridinium hexafluorophosphate [HPy][PF₆] ionic liquid (IL) as an extractant solvent was proposed for the preconcentration of trace levels of zinc as a prior step to determination by flame atomic absorption spectrometry (FAAS). Zinc was complexed with 8-hydroxyquinoline (oxine) and extracted into ionic liquid. Some effective factors that influence the microextraction efficiency such as pH, oxine concentration, amount of IL, ionic strength, temperature and centrifugation time were investigated and optimized. In the optimum experimental conditions, the limit of detection (3 s) and the enhancement factor were 0.22 μg L⁻¹ and 71, respectively. The relative standard deviation (RSD) for six replicate determinations of 13 μg L⁻¹ Zn was 1.92%. In order to validate the developed method, a certified reference material (NIST SRM 1549) was analyzed and the determined values were in good agreement with the certified values. The proposed method was successfully applied to the trace determination of zinc in water and milk samples.     

A CONVENIENT METHOD FOR THE SYNTHESIS OF PHOSPHOROTHIOATES AND THEIR ANTICHOLINESTERASE ACTIVITIES

A simple, efficient, and general method has been developed for the synthesis of phosphorothioates through a one-pot reaction of alkyl halides with the mixture of diethyl phosphite in the presence of NH ₄ OAc/S/CaO under solvent–free conditions. The anticholinesterase activities of eight different phosphorothioates were investigated on acetylcholinesterase from electric eel.     

Aromatization of 1,4-Dihydropyridines Under Mild and Heterogeneous Conditions

A combination of Mg(HSO₄)₂ and NaNO₂ in the presence of wet SiO₂ was used as an effective oxidizing agent for the oxidation of dihydropyridines to their corresponding pyridine derivatives at room temperature with moderate to excellent yields.