Click Synthesis of 1,2,3-Triazole Nucleosides Based on Functionalized Nicotinonitriles

Russian Journal of Organic Chemistry - A facile synthesis of a new series of 1,2,3-triazolyl nucleosides via one-pot click reaction is described. Acetylenic nicotinonitriles synthesized previously...     

Investigation of novel composites to be used as backfill materials in radioactive waste disposal facilities

Journal of Radioanalytical and Nuclear Chemistry - The current work aims at the preparation and characterization of novel composite materials of acrylic acid/charcoal/montmorillonite (MMT) (PAACM...     

Development of a novel LC–MS/MS method for detection and quantification of tramadol hydrochloride in presence of some mislabeled drugs: Application to counterfeit study

Counterfeiting of pharmaceuticals has become a serious problem all over the world, particularly in developing countries. In the present work, a highly sensitive LC–MS/MS method was developed for simultaneous determination of tramadol hydrochloride in the presence of some suspected mislabeled drugs such as alprazolam, diazepam, chlorpheniramine maleate, diphenylhydramine and paracetamol. The prepared samples were analyzed on an API 4000 mass spectrometer using an Eclipse C₁₈ column (3.5 μm, 4.6 × 100 mm). The mobile phase consisting of 0.01% formic acid, acetonitrile and methanol (60:20:20 v/v/v) was pumped with an isocratic elution at a flow rate of 0.7 mL min^?1. The detection was achieved on a triple quadruple tandem mass spectrometer in multiple reaction monitoring mode. The proposed method was successfully validated according to International Conference on Harmonization guidelines with respect to accuracy, precision, linearity, limit of detection and limit of quantitation. The calibration linear range for tramadol hydrochloride, alprazolam, diazepam, chlorpheniramine maleate, diphenylhydramine and paracetamol was 5–500 ng mL^?1. The results revealed that the applied method is promising for the differentiation of genuine tramadol tablets from counterfeit ones without prior separation.     

Electrochemical behavior of Al2O3/Al composite coated Al electrodes through surface mechanical alloying in alkaline media

The behavior of $A{l}_2{O}_3/Al$ composite coated Al electrodes fabricated by surface mechanical alloying ‘SMA’ was studied. The work was accomplished using Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques in alkaline media $2MKOH$ were done at room temperature. Results show hydroxyl ions accumulate on the surface due to Al deformation micro cavities filling with $A{l}_2{O}_3$ until full charge blockage reached. A barrier cover layer development causing an increase of both resistance and capacitance as it becomes more stable and thinner with exposure time increase. Migrating hydroxyl ion inside micro cavity changed its composition from Al₂O₃ to stable tetrahedral $Al{\left(OH\right)}_4^{?}$ aluminate ions. Therefore future benefits could be reached by developing such surfaces having charge accumulation that enables environmental interaction.     

Morphological and Interaction Characteristics of Surface-Active Ionic Liquids and Palmitic Acid in Mixed Monolayers

A series of water soluble, surface-active ionic liquids (SAILs), namely, 1-alkyl-3-methyl imidazolium chlorides ([C_n-mim]Cl) and their mixtures with palmitic acid (PA) are investigated in Langmuir monolayers and Langmuir–Blodgett films. It is inferred from the surface pressure-area isotherms that C₁₆-mim-IL mixes non-ideally with PA and stabilizes the binary mixed films. In addition, the residence of mim-IL at the water surface is enhanced as a function of the increasing alkyl side chain length. Generally, the compressional moduli values decrease upon increasing the content of the mim-ILs over a wide range of compositions. Furthermore, film relaxation measurements indicate that the IL component is selectively excluded from the mixed films upon achieving a certain target pressure. Brewster angle microscope images demonstrate minimal changes on the PA domains in the presence of either C₄- and C₈-mim-ILs, whereas presence of the hexadecyl counterpart results in the formation of condensed sheets. Atomic force microscopy imaging of deposited films show the formation of propeller-like aggregates when C₈- or C₁₆-mim-IL is present in the mixed films.     

Utility of 2-furan-2-yl-4-mercapto-6-methylpyrimidine-5-carbonitrile as a precursor for the synthesis of some novel pyrimidines: antibacterial activity

The starting material 2-furan-2-yl-4-mercapto-6-methylpyrimidine-5-carbonitrile 3 was reacted with various reagents resulting in the formation of a group of new pyrimidines and condensed pyrimidines including quinazoline 6 tetrazolopyrimidine 12, pyrazolopyrimidines 14, 18, and 19, triazolopyrimidine 16, and pyrimidopyridazine 20. The antibacterial activity was evaluated for a group of the synthesized compounds against examples of Gram-positive and Gram-negative bacteria.     

Crystal Structures and Spectral Studies of [Ph3Sn(O2AsMe2)], [Bu2ClSn(O2AsMe2)] and [PhClSn(O2AsMe2)(μ‐OMe)]2

[Ph₃Sn(O₂AsMe₂)] ( 1 ) and [PhClSn(O₂AsMe₂)(μ‐OMe)]₂ ( 3 ) have been synthesized by treatment of Ph₃SnCl and Ph₂SnCl₂ with Na(O₂AsMe₂) in methanol, respectively. [Bu₂ClSn(O₂AsMe₂)] ( 2 ) has been prepared by the reaction of Bu₂SnCl₂ with HO₂AsMe₂ in methanol. X‐ray diffraction studies show 1 to crystallize in the monoclinic space group P2₁/n with a = 699.8(1), b = 1961.4(2), c = 1433.6(2) pm, β = 95.17(1)°, and Z = 4. 2 also crystallizes monoclinic in the space group P2₁/m, the cell parameters being a = 480.6(1), b = 1992.7(2), c = 808.8(1) pm, β = 103.726(5)°, and Z = 2. Both compounds form infinite chains with alternating (Me₂AsO₂)^? and (R₃Sn)⁺ or (R₂ClSn)⁺ units. The dimer 3 consists of 8‐membered (OSnOAs)₂ rings in which the tin atoms are bridged by methanolate bridges. It crystallizes triclinic in the space group with a = 822.8(2), b = 910.4(2), c = 929.2(2) pm, α = 77.04(3)°, β = 82.35(3)°, γ = 68.69(3)°, and Z = 1 for the dimer. The vibrational and mass spectra of 1 , 2 and 3 are given and discussed.     

Synthesis and reactions of 3‐pyrrolidinones

This review presents a survey of the synthetic methods and reactions of 3‐pyrrolidinones I (R = H, alkyl, acyl, ester; R₁ = H, alkyl, cyano, ester, etc). 3‐Pyrrolidinones are synthetically versatiles substrate, as they can be used for synthesis of a large variety of heterocyclic compounds, such as indoles and 5‐deazapteroic acid analogues and as a raw material for drug synthesis. The high reactivity of an active methylene group next to the carbonyl of the pyrrolidine ring is useful for various syntheses.     

Adsorption Kinetics,Equilibrium, and Thermodynamics of Copper From Aqueous Solutions using Silicon Carbide Derived from Rice Waste

Adsorption of Cu(II) from aqueous solution on a novel adsorbent, silicon carbide ash (SiC ash), was studied using batch technique. The adsorbent was prepared by pyrolysis of Egyptian rice waste (rice straw and rice husk) and was characterized by scanning electron microscopy (SEM), energy-dispersive x-ray (EDX), Fourier-transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), and surface area analysis by Brunauer-Emmett-Teller (BET) Theory. The influence of pH, contact time, initial Cu(II) concentration, adsorbent dose, agitation speed, and temperature was investigated. Adsorption kinetics was analyzed using the pseudo-first-order, the pseudo-second-order, and intraparticular diffusion model. The adsorption process was found to follow a pseudo-second-order rate mechanism. The adsorption isotherm data could be well described by the Langmuir and Freundlich than the Dubinin–Radushkevich adsorption model. The adsorption capacity of 22.06 mg g^?1for SiC ash was obtained at pH = 5 and temperature of 298 K. Thermodynamic parameters, change in the free energy (ΔG°), the enthalpy (ΔH°), and the entropy (ΔS°), were also calculated. The overall adsorption process was exothermic, spontaneous in nature, and proceeds with decreased randomness as the entropy is negative value. Adsorption process was successfully applied to remove Cu(II) from an industrial wastewater sample.