Tetra‐n‐butylammonium Hydroxide (TBAH)–Catalyzed Knoevenagel Condensation: A Facile Synthesis of α‐Cyanoacrylates, α‐Cyanoacrylonitriles,and α‐Cyanoacrylamides

Tetra‐n‐butylammonium hydroxide (TBAH) has been utilized as a novel and efficient catalyst for the Knoevenagel condensation of aldehydes with acidic methylene compounds such as methyl‐ and ethylcyanoacetate, malononitrile, and cyanoacetamide to afford substituted olefins.     

One-Pot,Three-Component Uncatalyzed Quantitative Synthesis of New Aminonaphthols (Betti Bases) in Water

One-pot, three-component reaction of 2-naphthol, aromatic aldehyde, and heteroaryl amine in water at room temperature leads to the formation of the corresponding aminonaphthols (Betti bases). Reaction details and study of enantiomeric resolution of 1-(p-methylphenyl (2-pyrazinylamino) methyl) naphthalene-2-ol with the aid of ¹H NMR spectroscopy using chiral europium shift reagent is presented.     

Darzens Reaction Promoted by KF/Alumina: A Novel Stereoselective Method for Rapid and Efficient Synthesis of trans‐α,β‐Epoxy Ketones

The Darzens condensation of α‐chloroacetophenone with various aromatic aldehydes mediated by potassium fluoride on alumina at room temperature resulted in formation of good to excellent yields of trans‐α,β‐epoxy ketones in short time periods.     

Combined effect of gamma irradiation and hot water dipping on the selected nutrients and shelf life of peach

Gamma irradiation in combination with hot water dipping treatment was tested for maintaining storage quality and extending the shelf life of peach fruit. The matured peaches fruits (local variety no, Tex-A-6-69) were first dipped in hot water having temperature of 0, 40 and 60 °C for 60 seconds and they were exposed to 0.5 and 1.0 kGy doses of gamma radiation and stored in paper cartons under ambient (temperature 25 ± 2 °C, RH 70 %) conditions for their physico-chemical evaluations on weekly basis. The combine effect of hot water dipping treatment and irradiation for peach was study for the first time in Pakistan. The parameters studied included % weight loss, % ash content, % moisture content, total soluble solids (TSS), titratable acidity and ascorbic acid. The sensory indices studied were size, shape, color and overall acceptability. The sensory evaluation values at 0 days for the controlled peach sample were recorded for comparison. Statistical analysis was performed to find determinates of irradiation alone and in combination with hot water dipping techniques on peaches. Studies revealed that irradiation treatment in combination with hot water treatments significantly (LSD at 5 %) maintained the storage quality of peach fruit under ambient conditions. Data obtained for weight loss, moisture, shape and overall acceptability showed significant results while non-significant values were recorded for ash, TSS and size. Overall, consumers rated the acceptability of treated peaches higher than untreated peaches. This particular type of research also helps in improving one’s country export quality of fruits.     

Application of Crosslinked Acrylamidoxime/2-Acrylamido-2-methylpropane Sulfonic Acid Copolymer in Wastewater Treatment

Crosslinked acrylonitrile/acrylamidoxime/2-acrylamido-2-methylpropane sulfonic acid (AN/AAx/AMPS) based hydrogels was prepared by radical solution polymerization technique. The structures of hydrogels were characterized by FTIR analysis and the results were consistent with the expected structures. These hydrogels were used for the separation of Cd(II), Cu(II), and Fe(III) ions from their aqueous solutions. The influence of the uptake conditions such as pH, time, and initial feed concentration on the metal ion binding capacity of hydrogel was also tested. The selectivity of the hydrogel toward the different metal ions tested was Cd(II)>Fe(III)>Cu(II). The recovery of metal ions was also investigated in acid media.     

Rapid and facile synthesis of acyl azides from acyl halides using a polymer-supported azide ion under heterogeneous conditions

In this article a rapid and facile method for synthesis of acyl azide is described. The cross-linked poly(N-methyl-4-vinylpyridinium) azide ion, [P₄-VP]N₃ is prepared and used as an efficient polymeric reagent for synthesis of acyl azides from acyl halides at room temperature under heterogeneous conditions. Various benzoyl halides, with electron-withdrawing groups as well as electron-donating groups, were transformed into the corresponding benzoyl azides in high to excellent yields in short reaction times. The acyl azide products were characterized by FT-IR, and some of them were also characterized by ¹H-and/or ¹³C-NMR spectroscopy, and physical properties were compared to literature values of known compounds. The spent polymeric reagents can be regenerated and reused for several times without losing their activity. Relative to the reported methods, the present method has the advantages of operational simplicity, mild reaction conditions, fast reaction rates, simple reaction work-up and lower hazardous and potentially explosive nature. Also the present method is the first procedure for the synthesis of acyl azides from acyl halides by using a polymer-supported azide ion under heterogeneous conditions.     

Extraction and preconcentration of tylosin from milk samples through functionalized TiO2 nanoparticles reinforced with a hollow fiber membrane as a novel solid/liquid‐phase microextraction technique

The aim of this study was to introduce a novel, simple, and highly sensitive preparation method for determination of tylosin in different milk samples. In the so‐called functionalized TiO₂ hollow fiber solid/liquid‐phase microextraction method, the acceptor phase is functionalized TiO₂ nanoparticles that are dispersed in the organic solvent and held in the pores and lumen of a porous polypropylene hollow fiber membrane. An effective functionalization of TiO₂ nanoparticles has been done in the presence of aqueous H₂O₂ and a mild acidic ambient under UV irradiation. This novel extraction method showed excellent extraction efficiency and a high enrichment factor (540.2) in comparison with conventional hollow fiber liquid‐phase microextraction. All the experiments were monitored at λ_max = 284 nm using a simple double beam UV‐visible spectrophotometer. A Taguchi orthogonal array experimental design with an OA₁₆ (4⁵) matrix was employed to optimize the factors affecting the efficiency of hollow fiber solid/liquid‐phase microextraction such as pH, stirring rate, salt addition, extraction time, and the volume of donor phase. This developed method was successfully applied for the separation and determination of tylosin in milk samples with a linear concentration range of 0.51–7000 μg/L (r² = 0.991) and 0.21 μg/L as the limit of detection.     

Synthesis,crystal structure,and properties of hybrid-3D copper tetraphosphonate: [Cu3((HO3PCH2)2N–CH2C6H4CH2–N(CH2PO3H)2)(H2O)4] n

The new copper(II) tetraphosphonate, [Cu₃(HO₃PCH₂)₂N–CH₂C₆H₄CH₂–N(CH₂PO₃H)₂)(H₂O)₄] _n (1) was hydrothermally synthesized from the reaction of Cu(NO₃)₂ and (H₂O₃PCH₂)₂N–CH₂C₆H₄CH₂–N(CH₂PO₃H₂)₂, (H₈L). Compound 1 was structurally characterized by means of X-ray single crystal diffraction. The structure of 1 showed a 3D structure constructed from two types of Cu(II) and chelating and bridging modes of (HO₃PCH₂)₂N–CH₂C₆H₄CH₂–N(CH₂PO₃H)₂, and features a (4⁴.6¹⁰.8) topological network. The 3D compound is further stabilized by hydrogen bonds. UV–Vis diffuse reflectance and infrared spectroscopy as well as elemental analysis of compound 1 are also presented.     

UV-Visible Spectrophotometric Investigations of Charge Transfer Complexes of Some P-N,N-Dimethylaminobenzylidene Ailines with the New Acceptor PFB and CA Acceptor

The CT complexes of PFB and CA acceptors with eleven benzylidene anilines donors have been investigated spectro-photometrically in the uv-visible region for the first time. The values of Ip of these compounds have been estimated from their complexes with CA, the values are in the range of 8.64–8.96 ev. From these values the constants of the new acceptor PFB a, b, c₁, c₂ and Ea have been calculated, the values are 0.91, -5.31, 7.13, 1.97, and 1.37 ev, respectively. The CT parameters of our donors with PFB and CA acceptors, ζCT, ^KCT ΔG° and W have also been estimated and discussed.