Rapid and efficient one-pot synthesis of 1,4-dihydropyridine and polyhydroquinoline derivatives through the Hantzsch four component condensation by zinc oxide

A one-pot four-component reaction of aldehydes, ethyl acetoacetate/5,5-dimethyl-1,3-cyclohexanedione, ethyl acetoacetate and ammonium acetate in the presence of 10 mol% of ZnO as a heterogeneous catalyst for the synthesis of corresponding 1,4- dihydropyridine and polyhydroquinoline derivatives via the Hantzsch condensation is described. The present methodology offers several advantages such as simple procedure, excellent yields, and short reaction time.     

A convenient synthesis of some α-oxoketene-N,S- and N,N-acetals

Some α-oxoketene-N,S- and N,N-acetals were selectively synthesized in good to excellent yields by the reaction of 1,1-dimethoxy-4,4-di(methylthio)-3-buten-2-one with primary and secondary amines under moderate conditions. Secondary amines in reaction with α-oxoketene dithioacetal yielded double-substitution products exclusively, whereas primary amines under the same conditions yielded the mono-substituted products as exclusive or main products.     

Fabrication of durable superhydrophobic nanofibrous filters for oil‐water separation using three novel modified nanoparticles (ZnO‐NSPO,AlOO‐NSPO,and TiO2‐NSPO)

Three reusable and durable superhydrophobic nanofibrous filters were prepared by dip coating the nanofibrous fabric in the three different dispersed solutions of the newly modified nanoparticles (ZnO‐NSPO, AlOO‐NSPO, and titanium dioxide [TiO₂]‐NSPO). The contact angle results proved that the TiO₂‐NSPO coated nanofibrous polyacrylonitrile (PAN) filter was hydrophobic with the water contact angle (WCA) of 141° while the ZnO‐NSPO and AlOO‐NSPO coated nanofibrous PAN filters were superhydrophobic with the WCA of 168° and 152°, respectively. The as‐prepared filters can be utilized as an effective martial for oil‐water separation with separation efficiency of over 98%.     

Polybutylene terephthalate-nickel oxide nanocomposite as a fiber coating

A highly efficient polybutylene terephthalate (PBT)-based nanocomposite containing nickel oxide nanoparticles was synthesized by electrospinning technique and used as a fiber coating for solid phase microextraction. The influential morphological parameters and capability of the prepared nanocomposite including the NiO content, the coating time, the PBT concentration and applied voltage were considered for optimization. The applicability of the synthesized fiber coating was examined by headspace solid phase micro extraction and gas chromatography mass spectrometry detection of some volatile organic compounds in aqueous samples. Among the synthesized nanocomposites and pristine PBT nanofibers, the fiber coating with 14% of NiO nanoparticles doping level exhibited the highest extraction efficiency. In addition, important parameters influencing the extraction/desorption process were investigated and optimized. The detection limits were less than 5 ng L⁻¹ using the selected ion monitoring mode. The inter-day and intra-day precisions of the developed method under optimized conditions were below 11%. The method showed a linearity in the range of 10–1000 ng L⁻¹ with the correlation coefficient greater than 0.9987. The optimized method was applied to the sampling of some volatile organic compounds from real water samples. The developed method is convenient, rapid, simple, easy and inexpensive and offers high sensitivity and sufficient reproducibility.     

Label‐Free Electrochemical Aptasensor for Determination of Chloramphenicol Based on Gold Nanocubes‐Modified Screen‐Printed Gold Electrode

An ultrasensitive label‐free electrochemical aptasensor was developed for selective detection of chloramphenicol (CAP). The aptasensor was made using screen‐printed gold electrode modified with synthesized gold nanocube/cysteine. The interactions of CAP with aptamer were studied by cyclic voltammetry, square wave voltammetry (SWV) and electrochemical impedance spectroscopy. Under optimized conditions, two linear calibration curves were obtained for CAP determination using SWV technique, from 0.03 to 0.10 µM and 0.25–6.0 µM with a detection limit of 4.0 nM. The aptasensor has the advantages of good selectivity and stability and applied to the determination of CAP in human blood serum sample.     

Thermodynamic properties of solutions of sodium di-hydrogen phosphate in (1-propanol + water) mixed-solvent media over the temperature range of (283.15 to 303.15) K

The apparent molar volume and apparent molar isentropic compressibility of solutions of sodium di-hydrogen phosphate (NaH₂PO₄) in (1-propanol + water) mixed-solvent media with alcohol mass fractions of 0.00, 0.05, 0.10, and 0.15 are reported over the range of temperature (283.15 to 303.15) K at 5 K intervals. The results were fitted to a Redlich–Mayer type equation from which the apparent molar volume and apparent molar isentropic compressibility of the solutions at the infinite dilution were also calculated at the working temperature. The results show a positive transfer volume of NaH₂PO₄ from an aqueous solution to an aqueous 1-propanol solution. The apparent molar isentropic compressibility of NaH₂PO₄ in aqueous 1-propanol solutions is negative and it increases with increasing the concentration of NaH₂PO₄, 1-propanol, and temperature. Electrical conductivity and refractive index of the solutions are also studied at T = 298.15 K. The effects of the electrolyte concentration and relative permittivity of the medium on the molar conductivity were also investigated.     

A dispersive liquid–liquid microextraction based on a task-specific ionic liquid for enrichment of trace quantity of cadmium in water and food samples

In this work, a hydrophilic task-specific ionic liquid (TSIL) of 1-chloroethyl-3-methylimidazolium chloride functionalized with 8-hydroxyquinoline was used in a dispersive liquid–liquid microextraction method followed by flame atomic absorption spectrometry for the enrichment and determination of trace amounts of cadmium (Cd²⁺) ions. The simultaneous chelation and extraction of Cd²⁺ ions was carried out by the TSIL. Fine droplets of the water-immiscible TSIL containing target analyte were generated in situ by addition of an anion exchanger potassium hexafluorophosphate (KPF₆) salt to the sample tube. After phase separation by centrifugation for 4 min, the sedimented TSIL was diluted with acidified ethanol for measurement of Cd²⁺ content. Some significant parameters influence the preconcentration of Cd²⁺ ions such as sample pH, TSIL volume, amount of KPF₆, non-ionic surfactant and salt concentration were investigated. Under the optimal conditions, calibration curve was linear in the range of 5–250 µg L^?1 Cd²⁺ with correlation coefficient of 0.9975 and a detection limit of 0.55 µg L^?1. The relative standard deviation for six replicate measurements of 50 µg L^?1 Cd²⁺ was 1.5%. The method was successfully applied for the extraction and determination of Cd²⁺ ions in water and food samples.     

Spectroscopic (Ft-Ir,Nmr, Uv-Vis,Fluorescence) and Dft Studies (Molecular Structure,Ir and Nmr Spectral Assignments,Nbo and Fukui Function) of Schiff Bases Derived from 2-Chloro-3-Quinolinecarboxaldehyde

Two Schiff bases are newly prepared by the condensation of 2-chloro-3-quinolinecarboxaldehyde with ethylenediamine and 1,4-butanediamine. The Schiff bases are characterized by the elemental analysis, IR, ¹H and ¹³CNMR, UV-Vis, and fluorescence spectroscopies. Structural parameters together with the theoretical assignment of their vibrational frequencies and NMR chemical shifts are determined using density functional theory (DFT) approaches. There is good consistency between the DFT-calculated results and the experimental data, confirming the validity of the optimized geometries for the investigated Schiff bases. Optimized geometries of two Schiff bases are not planar, however, the substitutions are essentially in the same plane with the pyridine rings. Shapes of the frontier orbitals are determined using the natural bond orbital (NBO) analysis. Due to a high energy gap between the frontier orbitals, both Schiff bases are stable. Based on the Fukui function analysis, two Cl atoms and two azomethine nitrogen atoms are four suitable donor atoms for coordination to metal ions. Effects of the temperature and pH on the UV-Vis absorbance and fluorescence intensity of the Schiff bases are studied in a DMSO solution.     

Cold atmospheric plasma modification of curcumin loaded in tri‐phosphate chitosan nanoparticles enhanced breast cancer cells apoptosis

The anti‐cancer mechanisms of curcumin have been reported to include suppressions of angiogenesis and tumor proliferation. The main goal of this research is to increase the solubility of curcumin by cold atmospheric plasma (CAP) and assess the effects of modified curcumin by charging with tri‐polyphosphate chitosan nanoparticles for MCF‐7, MDA‐MB‐231 breast cancer cells, and human fibroblast cells. Curcumin modification was done by CAP and its solubility was evaluated by spectrophotometry. After loading modified curcumin into nano‐chitosan‐TPP, nanocurcumin was characterized by scanning electron microscopy. Cellular viability and apoptosis of treated cells were assessed by MTT and Annexin V. The changes of messenger RNA expression of TP5353 and VEGF genes were analyzed by real‐time PCR. CAP was able to transform the curcumin to possess hydrophilic characteristics after 90 seconds. The mean diameter of Curcumin loaded chitosannanoparticles (NPs) were determined as 48 nm. MTT results showed that the IC₅₀ of nano Cur‐chitosan‐TPP was effectively decreased compared to free curcumin in MCF‐7 (15 μg/mL at 72 hours vs 20 μg/mL at 48 hours). Additionally, nano Cur‐chitosan‐TPP had no significant effect on normal cells (Human dermal fibroblas: HDF), whereas it also decreased the viability of triple negative breast cancer cell line (MDA‐MB‐231). Real‐time PCR results showed that expression level of TP53 gene was upregulated (P = .000), whereas VEGF gene downregulated (P = .000) in treated MCF‐7 cells. Curcumin loaded chitosan nanoparticles have led to an induction of apoptosis (79.93%) and cell cycle arrest (at S and G2M). Modified‐curcumin‐tri‐polyphosphate chitosan nanoparticles using CAP can be considered as a proper candidate for breast cancer treatment.