Caesium carbonate supported on hydroxyapatite‐encapsulated Ni0.5Zn0.5Fe2O4 nanocrystallites as a novel magnetically basic catalyst for the one‐pot synthesis of pyrazolo[1,2‐b]phthalazine‐5,10‐diones

A novel nanomagnetic basic catalyst of caesium carbonate supported on hydroxyapatite‐coated Ni_0.5Zn_0.5Fe₂O₄ magnetic nanoparticles (Ni_0.5Zn_0.5Fe₂O₄@HAP‐Cs₂CO₃) was prepared. This new catalyst was fully characterized using Fourier transform infrared spectroscopy, transmission and scanning electron microscopy, X‐ray diffraction and vibrating sample magnetometry techniques, and then the catalytic activity of this catalyst was investigated in the synthesis of 1H‐pyrazolo[1,2‐b]phthalazine‐5,10‐dione derivatives. Also, Ni_0.5Zn_0.5Fe₂O₄@HAP‐Cs₂CO₃ could be reused at least five times without significant loss of activity and could be recovered easily by applying an external magnet. Thus, the developed nanomagnetic catalyst is potentially useful for the green and economic production of organic compounds. Copyright © 2015 John Wiley & Sons, Ltd.     

Highly effective and regioselective Michael addition of indoles to α,β-unsaturated ketones promoted by pentafluorophenylammonium triflate

A simple, inexpensive, environmentally friendly and efficient route for Michael addition of indoles to α,β-unsaturated ketones using pentafluorophenylammonium triflate (PFPAT) as a catalyst is described. Various indole derivatives were synthesized in good to excellent yields. The preparation of PFPAT catalyst from simple and readily available starting materials makes this method more affordable.     

Impregnated copper ferrite on mesoporous graphitic carbon nitride: An efficient and reusable catalyst for promoting ligand‐free click synthesis of diverse 1,2,3‐triazoles and tetrazoles

Magnetic CuFe₂O₄/g‐C₃N₄ hybrids were synthesized through a facile method and their catalytic performances were evaluated in click chemistry for the first time. The structural and morphological characterization of prepared materials was carried out by different techniques such as X‐ray diffraction, high‐resolution transmission electron microscopy, field emission scanning electron microscopy, Fourier infrared spectroscopy, vibrating sample magnetometry, thermogravimetric analysis, and N₂ adsorption–desorption analysis (Brunauer–Emmett–Teller surface area). The utilization of magnetic CuFe₂O₄/g‐C₃N₄ enabled superior performance in the one‐pot azide–alkyne cycloaddition reaction in water using alkyl halides and epoxides as azide precursors without the need of any additional agents. The present system is broad in scope and especially practical for the synthesis of macrocyclic triazoles and also tetrazoles. In addition, the catalytic system highly fulfills the demands of “green click chemistry” with its convenient conditions, especially easy access to a variety of significant products in low catalyst loading and simple work‐up and isolation procedure.     

Homogeneous Liquid–Liquid Microextraction Via Flotation Assistance (HLLME-FA) Method for the Pretreatment of Organochlorine Pesticides in Aqueous Samples and Determination by GC–MS

This work proposes a new, rapid and simple homogeneous liquid–liquid microextraction via flotation assistance technique for the analysis of six organochlorine pesticides in water samples. A special extraction cell was used to facilitate collection of the low-density solvent extract. No centrifugation was required in this procedure. Determination was carried using gas chromatography–mass spectrometry. The water sample solution was then added into the extraction cell containing appropriate mixture of extract and homogeneous solvents. In the first step, a homogeneous solution and then with the continuation of water sample injection, a cloudy solution was formed. Using air flotation, the organic solution was collected at the conical part of the designed cell. The optimized levels of effective parameters were found based on response surface methodology approach. Applying the optimized conditions to the system understudy, the limits of detection of all target analytes were obtained in the range of 1.4–7 ng mL^?1, while the precisions were found to be in the range of 11.08–14.87 (RSD, n = 3). The linearity of the method lay in the range of 10–150 ng mL^?1 with the coefficients of correlation (r ² ) ranging from 0.998 to 0.999.     

Synthesis of Diaryl Ethers Through the Copper-Catalyzed Arylation of Phenols with Aryl Iodides Using KF/Al2O3

An efficient synthesis of diaryl ethers by the copper-catalyzed arylation of phenols with a variety of aryl iodide susing KF/Al₂O₃ as a suitable base and CuI and 1,3 diphenyl-1,3 propandione as the catalyst is described.     

Novel amide derivatives of 3-phenylglutaric acid as potent soluble epoxide hydrolase inhibitors

Molecular Diversity - Soluble epoxide hydrolase (sEH) enzyme plays an important role in the metabolism of endogenous chemical mediators, epoxyeicosatrienoic acids, which are involved in the...     

Investigation of a mutual interaction force at different pressure amplitudes in sulfuric acid

This paper investigates the secondary Bjerknes force for two oscillating bubbles in various pressure amplitudes in a concentration of 95% sulfuric acid.The equilibrium radii of the bubbles are assumed to be smaller than 10 μm at a frequency of 37 kHz in various strong driving acoustical fields around 2.0 bars (1 bar=10 5 Pa).The secondary Bjerknes force is investigated in uncoupled and coupled states between the bubbles,with regard to the quasi-adiabatic model for the bubble interior.It finds that the value of the secondary Bjerknes force depends on the driven pressure of sulfuric acid and its amount would be increased by liquid pressure amplitude enhancement.The results show that the repulsion area of the interaction force would be increased by increasing the driven pressure because of nonlinear oscillation of bubbles.     

Magnetoelastic properties of Nd6Fe13Cu intermetallic compound

Magnetoelastic properties of Nd₆Fe₁₃Cu intermetallic compound are reported. To study the magnetoelastic behaviour of this compound, the thermal expansion as well as the longitudinal (λ_l) and transverse (λ_t) magnetostriction were measured by using the strain gauge method in the selected temperature range of 80-500 K under applied magnetic fields up to 1.5 T. An anomaly and invar-type effects are observed in the linear thermal expansion and α(T) curves at the Néel temperature. The linear spontaneous magnetostriction decreases sharply by approaching the Néel temperature and also shows the short-range magnetic ordering effects when antiferromagnetic-paramagnetic transition occurs. In the low field region, the absolute values of the anisotropic magnetostriction are small and then start to increase with applied magnetic field. Each isofield curve of the anisotropic magnetostriction passes through a minimum and then approaches to zero with increasing temperature. This magnetostriction compensation arises from the difference in the magnetoelastic coupling constants of the sublattices in this compound.