Ca(NO3)2•4H2O-catalysed Biginelli Reaction: One-pot Synthesis of 1,2,3,4-Tetrahydropyrimidin-2-ones/pyrimidine-2-thiones under Solvent-free Conditions

The synthesis of 1,2,3,4-dihydropyrimidinone/thione derivatives was achieved in good to excellent yields using calcium(II) nitrate as catalyst to promote the Biginelli three-component condensation reaction from a diversity of aromatic aldehydes, β-keto compounds and urea or thiourea. The reaction was carried out under solvent-free conditions.     

Simultaneous quantification of levofloxacin,pefloxacin, ciprofloxacin and moxifloxacin in microvolumes of human plasma using high‐performance liquid chromatography with ultraviolet detection

Levofloxacin, pefloxacin, ciprofloxacin and moxifloxacin are four fluoroquinolones used in the treatment of serious bacterial infections. The antibacterial activity of fluoroquinolones is concentration dependent. Therefore, therapeutic drug monitoring in daily clinical practice is warranted to ensure the therapy's efficacy and prevent bacterial resistance. The purpose of the present study was to develop a method using high‐pressure liquid chromatography with an ultraviolet detector for simultaneous quantification of these four fluoroquinolones in human plasma. A 50 μL aliquot of plasma was precipitated by 200 μL of methanol using gatifloxacin as internal standard. The chromatographic separation was performed on a Kinetex XB‐C₁₈ column using a mobile phase composed of a mixture of orthophosphoric acid 0.4% (v/v), acetonitrile and methanol at a flow rate of 1.2 mL/min. Dual UV wavelength mode was used, with levofloxacin and moxifloxacin monitored at 293 nm, and pefloxacin and ciprofloxacin monitored at 280 nm. The calibration was linear over the ranges of 0.125–25 mg/L for levofloxacin, 0.1–20mg/L for moxifloxacin and 0.05‐10 mg/L for both pefloxacin and ciprofloxacin. Inter‐ and intra‐day trueness and precision were <13% for all the compounds under study. The proposed method was simple, reliable, cost‐effective and suitable for therapeutic drug monitoring or pharmacokinetics studies.     

Synthesis and Biological Activity of New Chiral N‐Acylsulfonamide Bis‐oxazolidin‐2‐ones

A new series of chiral 5‐substituted bis‐oxazolidinones containing an acylsulfonamide moiety has been synthesized starting from chlorosulfonyl isocyanate, (l )‐ethyl lactate, and oxazolidin‐2‐ones. All the reactions were conducted at ambient temperature, and the N‐acylsulfonamide bis‐oxazolidin‐2‐ones were obtained with high yields within 2 h. Some of the newly synthesized compounds were evaluated in vitro against the virulent strain RH of Toxoplasma gondii and the human lymphocytes, and showed promising results.     

Removal of Cd(II), Cu(II), and Pb(II) by adsorption onto natural clay: a kinetic and thermodynamic study

In this work, we study the elimination of three bivalent metal ions (Cd²⁺, Cu²⁺, and Pb²⁺) by adsorption onto natural illitic clay (AM) collected from Marrakech region in Morocco. The characterization of the adsorbent was carried out by X-ray fluorescence, Fourier transform infrared spectroscopy and X-ray diffraction. The influence of physicochemical parameters on the clay adsorption capacity for ions Cd²⁺, Cu²⁺, and Pb²⁺, namely the adsorbent dose, the contact time, the initial pH imposed on the aqueous solution, the initial concentration of the metal solution and the temperature, was studied. The adsorption process is evaluated by different kinetic models such as the pseudo-first-order, pseudo-second-order, and Elovich. The adsorption mechanism was determined by the use of adsorption isotherms such as Langmuir, Freundlich, and Temkin models. Experiments have shown that heavy metals adsorption kinetics onto clay follows the same order, the pseudo-second order. The isotherms of adsorption of metal cations by AM clay are satisfactorily described by the Langmuir model and the maximum adsorption capacities obtained from the natural clay, using the Langmuir isotherm model equation, are 5.25, 13.41, and 15.90 mg/g, respectively for Cd(II), Cu(II), and Pb(II) ions. Adsorption of heavy metals on clay is a spontaneous and endothermic process characterized by a disorder of the medium. The values of ΔH are greater than 40 kJ/mol, which means that the interactions between clay and heavy metals are chemical in nature.     

Design and synthesis of novel 1,3,4-oxadiazole based azaspirocycles catalyzed by NaI under mild condition and evaluated their antidiabetic and antibacterial activities

A modest, efficient, and mild synthetic procedure has been developed for the synthesis of novel series of 1,3,4-oxadiazole containing azaspirocycles derivatives. The reaction of 1,3,4-oxadiazole derivative with diverse azaspiro compounds under room temperature condition with helps of sodium iodide catalyst and polar aprotic solvent. Numerous compensations of this strategy embrace less time required, yield increment, consumption of all reactants, and mild condition. All synthesized compounds evaluated for in vitro antidiabetic and antibacterial screening. Among them some compounds show significant biological response.     

Nickel Supported on Alkaline Earth Metal–Doped γ-Al2O3–La2O3 as Catalysts for Dry Reforming of Methane

Russian Journal of Applied Chemistry - Nickel catalysts supported on γ–Al2O3 doped with La2O3 and alkaline earth oxides (MgO, CaO, and SrO) were investigated in the dry reforming of...     

Molecular dynamics comparative study of methane–nitrogen and methane–nitrogen–ethane systems

This work concerns the site–site interaction study of 256 particles using the Buckingham potential model. We have calculated the new parameters of the Buckingham potential using an iterative algorithm with a mean square method. This adapted model allows determining the characteristics for each state point. We have applied this model to study the liquefied natural gas LNG properties for methane-nitrogen and methane–nitrogen–ethane mixtures by molecular dynamics. We have calculated the thermodynamic, dynamic and structural properties for both the microcanonical NVT and the isothermal-isobaric NPT ensembles of binary and ternary systems from the SP₁ to SP₉ points. Then, we have compared the results between binary and ternary systems. We have obtained a good prediction on transport properties. From the calculated values of self-diffusion coefficient and viscosity, we have confirmed the liquid state of the liquefied natural gas LNG system.     

Stellatic acid: a new class of sesterterpenoid; X-ray crystal structure

The complete structure of a unique tricyclic sesterterpene, stellatic acid, was established by X-ray diffraction of its p-bromophenacyl ester.     

The Nephroprotective Effect of Zizyphus lotus L. (Desf.) Fruits in a Gentamicin-Induced Acute Kidney Injury Model in Rats: A Biochemical and Histopathological Investigation

Zizyphus lotus L. (Desf.) (Z. lotus) is a medicinal plant largely distributed all over the Mediterranean basin and is traditionally used by Moroccan people to treat many illnesses, including kidney failure. The nephrotoxicity of gentamicin (GM) has been well documented in humans and animals, although the preventive strategies against it remain to be studied. In this investigation, we explore whether the extract of Zizyphus lotus L. (Desf.) Fruit (ZLF) exhibits a protective effect against renal damage produced by GM. Indeed, twenty-four Wistar rats were separated into four equal groups of six each (♂/♀ = 1). The control group was treated orally with distilled water (10 mL/kg); the GM treated group received distilled water (10 mL/kg) and an intraperitoneal injection of GM (80 mg/kg) 3 h after; and the treated groups received ZLF extract orally at the doses 200 or 400 mg/kg and injected intraperitoneally with the GM. All treatments were given daily for 14 days. At the end of the experiment, the biochemical parameters and the histological observation related the kidney function was explored. ZLF treatment has significantly attenuated the nephrotoxicity induced by the GM. This effect was indicated by its capacity to decrease significantly the serum creatinine, uric acid, urea, alkaline phosphatase, gamma-glutamyl-transpeptidase, albumin, calcium, sodium amounts, water intake, urinary volume, and relative kidney weight. In addition, this effect was also shown by the increase in the creatinine clearance, urinary creatinine, uric acid, and urea levels, weight gain, compared to the rats treated only with the GM. The hemostasis of oxidants/antioxidants has been significantly improved with the treatment of ZLF extract, which was shown by a significant reduction in malondialdehydes levels. Histopathological analysis of renal tissue was correlated with biochemical observation. Chemical analysis by HPLC-DAD showed that the aqueous extract of ZLF is rich in phenolic compounds such as 3-hydroxycinnamic acid, catechin, ferulic acid, gallic acid, hydroxytyrosol, naringenin, p- coumaric Acid, quercetin, rutin, and vanillic acid. In conclusion, ZLF extract improved the nephrotoxicity induced by GM, through the improvement of the biochemical and histological parameters and thus validates its ethnomedicinal use.