One‐pot synthesis of highly functionalized benzo [1,3] thiazine from isocyanides,aniline, and heterocumulene via Cu‐catalyzed intramolecular C‐H activation reactions

A one‐pot synthesis of functionalized benzo thiazine derivatives via a Cu‐catalyzed, multicomponent reaction of isocyanides, aniline, and heterocumulenes in acetonitrile at room temperature was developed. Transition metal‐catalyzed activation of C‐H bonds under mild copper‐catalytic reaction conditions, using simple and available starting materials, also obtaining a pure product with high yield without applying column chromatography are the major advantages of the applied method among the other ones used for this purpose. The structures are confirmed spectroscopically (¹H‐ and ¹³C‐NMR, IR, and EI‐MS) and through elemental analyses.     

Solvent-Free Conditions as an Eco-Friendly Strategy for Synthesis of Organophosphorus Compounds

A series of diverse NH- and CH-acids are used for a one-pot synthesis of stable phosphorus ylides and 1,4-diionic organophosphorus compounds by trapping of the zwitterionic intermediate from the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates under solvent-free conditions. The structural geometry for one of the products was confirmed by single crystal X-ray diffraction analysis.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

ZnO-nanorods as economical catalyst for synthesis of 4-amino-2-iminodithiole derivatives using tetramethyl thiourea in water

4-amino-2-iminodithiole derivatives were synthesised via multi-component reactions of tetramethyl thiourea, isothiocyanates and alkyl bromides in the presence of ZnO nanorods (ZnO-NR) as the catalyst in water at ambient temperature. These reactions provide low yields without catalysts. The catalyst exhibited significant reusable activity.     

Fructose-catalyzed synthesis of tetrahydrobenzo[b]pyran derivatives：Investigation of kinetics and mechanism

Fructose was used as an efficient catalyst for three-component condensation reactions of aryl alde-hydes, malononitrile, and dimedone in a mixture of EtOH and H2O as green solvents. The advantages of t...     

Water-gas-shift reaction over nickel catalysts: DFT studies and kinetic modeling

Structural Chemistry - Density functional theory (DFT) calculations were used to study the mechanism of water gas shift (WGS) reaction on Ni (111) surfaces. Three sets of elementary reactions based...     

Dispersive Liquid‐Liquid Microextraction of Cu(II) Using a Novel Dioxime for Its Highly Sensitive Determination by Graphite Furnace Atomic Absorption Spectrometry

A dispersive liquid‐liquid microextraction (DLLME) technique was proposed for the enrichment and graphite furnace atomic absorption spectrometric (GFAAS) determination of Cu²⁺ in water samples. In this method a mixture of 480 μL acetone (disperser solvent) containing 26 μg S,S‐bis(2‐aminobenzyl)‐dithioglyoxime (BAT) ligand and 20 μL carbon tetrachloride (extraction solvent) was rapidly injected by a syringe into 5 mL aqueous sample containing copper ions (analyte). Thereby, a cloudy solution formed. After centrifugation, the fine droplets containing the extracted copper complex were sedimented at the bottom of the conical test tube. This phase was collected by a microsyring and after dilution by methanol, 20 μL of it was injected into the graphite tube of the instrument for analysis. Effects of some parameters on the extraction, such as extraction and disperser solvent type and volume, extraction time, salt concentration, pH and concentration of the chelating agent were optimized. The response surface method was used for optimization of the effective parameters on the extraction recovery. Under these conditions, an enrichment factor of 312 was obtained. The calibration graph was linear in the rage of 2–50 μ L⁻¹ Cu²⁺ with a detection limit of 0.03 μg L⁻¹ and a relative standard deviation (RSD) for five replicate measurements of 3.4% at 20 μg L⁻¹ Cu²⁺. The method was successfully applied to the determination of Cu²⁺ in some spring water samples.     

Kinetic and thermodynamic properties of the aerial oxidation of hydroquinone in developer solutions

The aerial oxidation kinetics of hydroquinone in a freshly prepared developer solution at different temperatures and pHs has been studied. The activation parameters, Ea, ΔG# , ΔS# , ΔH# and enthalpy of formation of activated complex, ΔHfo(X# ), are determined. The large negative value of free energy of activation ΔG# proves that hydroquinone extremely tends to be oxidized by air at optimum temperature (20℃) and optimum pH (10.5) and converts to the activated complex semiquinone. It was also found that if the pH of the developer solution is increased from 9.3 to 10.5 the reaction rate will increase by a factor of 2.