European Journal of Chemistry

A Grunwald-Winstein treatment of the specific rates of solvolysis of α-bromoisobutyro phenone in 100% methanol and in several aqueous ethanol, methanol, acetone, 2,2,2-trifluoroethanol (TFE), and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) mixtures gives a good logarithmic correlation against a linear combination of N_T (solvent nucleophilicity) and Y_Br (solvent ionizing power) values. The l and m sensitivity values are compared to those previously reported for α-bromoacetophenone and to those obtained from parallel treatments of literature specific rate values for the solvolyses of several tertiary mesylates containing a C(=O)R group attached at the α-carbon. Kinetic data obtained earlier by Pasto and Sevenair for the solvolyses of the same substrate in 75% aqueous ethanol (by weight) in the presence of silver perchlorate and perchloric acid are analysed using multiple regression analysis.

(-)-Epigallocatechin gallate (EGCG) is a catechin found in green tea that has potential health benefits, such as anti-oxidant, anti-carcinogenic and anti-inflammatory effects. A rapid and sensitive Ultra-Performance Liquid Chromatographic (UPLC) method was developed and validated for the estimation of (-)-epigallocatechin-3-gallate in lipid-based formulation. The UPLC method was conducted on C18 analytical column (50 mm × 2.1 mm, 1.8 μm particle size). The mobile phase consisted of a mixture of acetic acid (1%, v:v; pH = 3), acetonitrile and water at volume ratio of 13:15:72 delivered at a flow rate of 0.5 mL/min. The diode array detector (DAD) acquisition wavelength was set at wavelengths 210 and 280 nm. Caffeine was used as internal standard. The tested validation parameters, i.e., selectivity, linearity, accuracy, precision, and sensitivity (Limit of detection and limit of quantification) were determined at both wavelengths. Results revealed that caffeine and EGCG peaks were eluted at retention times of 0.55 and 0.85 minutes, respectively. The calibration curve was linear over the concentration range of 10-60 μg/mL, with coefficients of determination (r²) of 0.9993 and 0.9998 nm at 210 and 280 nm, respectively. All the validation parameters were found within the acceptable range. The proposed method was successfully applied for the quantitation of EGCG in lipid-based formulation and statistical analysis with a reported method showed no significant difference at p < 0.05. Therefore, the proposed analytical method for EGCG can be considered as a rapid, selective and accurate analytical method that can be used for the quantitative analysis of EGCG.

Nanoporous particles Ni(II) ion imprinted polymer (IIP), and non-imprinted polymer (NIP) in the absence of Ni(II) ion, with 18-70 nm dimensions were synthesized, and characterized by Fourier transform infrared, energy dispersive X-ray and nuclear magnetic resonance spectroscopic methods. Then, the surface area, pore size and structural composition of the products were characterized by Brunauer-Emmett-Teller and scanning electron microscope methods. Then, modified electrodes by the IIP for Ni(II) sensing and determination, were constructed and their catalytic activity were investigated by cyclic voltammetric method. Some parameters like desorption solvent, amount of sorbent, pH and contact time were optimized, and the measurements were all conducted under optimal conditions. The optimum pH for maximum sorption was obtained 7.8. In the optimum conditions, the maximum sorbent capacity of the IIP was obtained 371.9 µM/g. The limit of detection and relative standard deviation (n = 5) were obtained 1.3 ng/mLand 1.47%, respectively. The pre-concentration procedure revealed a linear curve within the concentration range of 10-6000 ng/mL and a good linearity with squared correlation coefficient of r² 0.9991 was achieved. The method was applied successfully for determination of Ni(II) ion in petrochemical samples.

In the present work, we report the synthesis of a series of 3-(substituted phenyl)-N-(2-hydroxy-2-(substituted-phenyl)ethyl)-N-methylthiophene-2-sulfonamide derivatives through Suzuki and Buchwald reaction. We have optimized methodology for targets from milligram to multi-gram scale. The newly synthesized compounds were characterized by ¹H NMR, ¹⁹F NMR, ¹³C NMR, LC-MS techniques and purity was further checked by HPLC. The compounds were evaluated for their in-vitro antiproliferative activity against MCF-7, HeLa, A-549 and Du-145 cancer cell lines by CCK-8 assay. The preliminary bioassay suggests that most of the compounds show antiproliferation with different degrees and 5-fluorouracil was used as positive control. Among these compounds 2d, 2g, 2i, 4e, 4h and 4k are most active compared to the standard. All the synthesized compounds show IC₅₀ values from 1.82-9.52 µM in different cell lines. Amongst these, compounds 2d, 2g, 2i, 4e, 4h and 4k were most potent, with IC₅₀ values ranging from 1.82-4.28 µM in different cell lines.

The synthesis, spectral, catalytic and antioxidant properties of ethyl-2-(2-hydroxy-3-methoxybenzylideneamino)-6-methyl-4,5,6-tetrahydrobenzo[b]thiophene-3-carboxylate (L) substituted iron(II), manganese(II), zinc(II), and ruthenium(II)-arene chlorides are described for the first time. The ligand and its metal complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, and spectral (¹H NMR, ¹³C NMR, FT-IR, UV-Vis and Mass) techniques. The FT-IR spectra showed that the ligand can act as bidentate or tridentate. Magnetic moments and electronic spectral studies revealed an octahedral geometry for all the complexes obtained. The thermal behavior of the complexes showed that the water molecules were separated in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. Ru(II) complex was used as catalysts for the transfer hydrogenation of ketones. At the same time, the effect of various bases such as NaOH, KOH, KOBu^t and NaOAc as organic base were investigated in the transfer hydrogenation of ketones by 2-propanol as the hydrogen source. The complexes and ligand were tested in vitro for their antioxidant activity. The experimental results showed that Ru(II) complex had more potent antioxidant activities than Zn(II), Fe(II), Mn(II) complexes and parent ligand.

Regioselective facile synthesis of innovative heterocycles from the reaction of 2-cyano-N-cyclohexylacetamide (3) with hydrazonoyl chloride (4) in basic condition afforded amino pyrazole derivative 6. The behavior of acetamide 3 with phenylisothiocyanate in DMF/KOH surveyed by addition of the α-halo ketones to yeild the corresponding thiophene derivative 13a, 13b, 16, 18 and 1,3-thiazoles 21. Reaction of intermediate potassium salt 9 with hydrazonoyl chloride 22a-e furnished the corresponding 1,2,4-thiadiazoles 24a-e. Density functional theory (DFT) calculations at the B3LYP and HF techniques combined with 6-31G(d) basis set to investigate the equilibrium geometry of the innovative compound pyrazoles 6 and the stability affording of HOMO/LUMO molecular orbitals.

Cadmium selenide nanocrystals were observed to have a size-dependent melting point which was depressed relative to the bulk melting temperature. The observed size-dependent melting point ranged from 500-1478 K, while a model based on the surface area to volume ratio predicted that is should range between 774-1250 K. The nanocrystals were heated in situ in the electron microscope, and the melting point was almost immediately followed by the vaporization of the CdSe nanocrystals, allowing for straightforward determination of the melting temperature. The differences between the observed melting point of CdSe nanocrystals and the values predicted by the surface area to volume ratio model indicates that additional factors are involved in the melting point depression of nanocrystals.

Pyrano[3,2-c]quinolones are commonly found in alkaloids, manifesting diverse biological activities. In this work, 2-amino-6-methyl-5-oxo-4-substituted-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carbonitriles and ethyl 2-amino-4-(substituted)-6-methyl-5-oxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carboxylates have been synthesized efficiently from reaction of 4-hydroxy-1-methylquinolin-2(1H)-one, aldehydes and active methylene nitriles in one-pot three component reaction in aqueous medium, containing catalytic amount of ethanolamine resulting in 70-95% yields.

The formation constants of Li(I), Mg(II), Sr(II), Ca(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Ba(II), Pb(II), Al(III), Cr(III), Fe(III) and Th(IV) ions with ambroxol hydrochloride (AMB) were calculated using the half-n value. In presence of 0.1 M NaNO₃, metal ions such as Zn(II), Cd(II), Ni(II), Cr(III), Li(I), Mg(II) and Al(III) forms three types of metal-ligand complexes (1:1, 1:2 and/or 1:3), while Sr(II) and Co(II) tend to form two types of metal complexes 1:1 and 1:2 (M:L). For ligand protonation constants, two logarithmic association constant values were calculated by the half-n method and are 10.7 and 7.6, respectively. The effect of ionic strength on stability constant of AMP, with different metal ions viz. Fe(III), Th(IV), Al(III), Cr(III) and Cu(II) was studied. Based on relationship between the ionic strength studied values and the 1^st stability constants (Log K₁^H), we can conclude that the stability constants of the formed metal-ligand complex (1:1) were decreased as the ionic strength increased. The stoichiometry of the formed complexes in solution were determined by conductometric method and it is found to be of 1:1, 1:2 and/or 1:3 (M:L) complex species is formed in alkaline media. Also, study the species distribution diagrams of AMP for the calculated mole fraction α_ML and α_ML2 were discussed.

A selective fluorescent sensor for Cu(II) ion in ethanol and acetone based on boradiazaindacene (BODIPY) has been studied. The selectivity towards Cu(II) ion is good over Ag(I), Cd(II), Fe(III), Hg(II), Ni(II), Pb(II), and Zn(II) ions, only Fe(III), Hg(II) and Ni(II) ions showed a slight interference. The solution showed strong fluorescence intensity after addition of triethanolamine, indicating that the Sensor 1-Cu(II) complex could be reversed by triethanolamine.