Iraqi National Journal Of Chemistry

This study aimed to prepare a series of novel heterocyclic compounds via the Schiff-Bass cycloaddition reaction of 4-((5-mercapto-1,3,4-thiadiazol-2-yl) imino)methyl)-2-nitrophenol. Schiff bases were used in the synthesis to produce novel Schiff base derivatives, including quinazoline, thiazine, oxazepine, imidazolidine, and tetrazole derivatives. The structures of the derivatives were determined by Fourier transform infrared spectroscopy, 1H NMR, and 13C NMR, and they were evaluated in vitro as antimicrobial and anticancer agents, with several exhibiting useful biological activity. All derivatives were evaluated in vitro for their antimicrobial activity. The new derivatives were studied in vitro against two bacterial species (Escherichia coli and Staphylococcus aureus). The results of the antimicrobial activity study showed encouraging antibacterial activity, with good inhibition rates for some of the studied derivatives compared to the antibiotic amoxicillin. An in vitro study of the product was conducted on the SKGT4 cell line (cancer cells). Cytotoxicity tests showed encouraging results for some of these targeted derivatives against the SKGT4 cell line, with low IC50 values. Theoretically, using a molecular docking program to study the targeted derivative, the cytotoxicity test results were confirmed. The results showed a good low binding energy compared to crizotinib.

A magnetically recoverable Brønsted acid catalyst, Fe3O4@SiO2-R-Chitosan-SO3H, was synthesized via a four-step process involving chitosan activation, amination, immobilization onto Fe3O4@SiO2, and sulfonation. FT-IR, XRD, and TGA-DTA analyses confirmed the formation of a stable organic–inorganic hybrid with preserved magnetic properties and a high density of strong acidic sites. The catalyst showed excellent performance in the ultrasound-assisted one-pot three-component synthesis of tetrahydrobenzo[b]pyran derivatives from malononitrile, dimedone, and aromatic aldehydes in ethanol. Under optimized conditions, yields of up to 94% were obtained within 1.5 h using only 0.05g of catalyst, with a TON of 11.1 and a TOF of 33.6 h-1. The catalyst exhibited broad substrate scope and maintained high activity over six consecutive cycles with minimal loss. The use of a green solvent, low catalyst loading, ultrasonic irradiation, and easy magnetic recovery underscores the sustainability and practical applicability of this catalytic system.

This study focuses on the synthesis of three heterocyclic compounds (M1a, M1b, M1c) through the esterification of vanillin with malic anhydride. The ester (M) was synthesized by reacting vanillin (4-hydroxy-3-methoxybenzaldehyde) with malic anhydride. A Schiff base was then formed by reacting the vanillin ester (M) with aniline, followed by an addition reaction to the C=N double bond, yielding the heterocyclic compounds. The compounds were characterized by thin-layer chromatography (TLC) and melting point determination, as well as by Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H-NMR), and carbon-13 nuclear magnetic resonance (¹³C-NMR). The synthesized compounds demonstrated superior antibacterial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria compared to ciprofloxacin. The inhibition zones for the compounds ranged from 18 to 25 mm for E. coli and S. aureus, compared to 12 to 15 mm for the drug. The heterocyclic compounds exhibited stronger antibacterial activity, with larger inhibition zone diameters compared to ciprofloxacin.

In this study, a new organic azo-Schiff base ligand was prepared in two steps: condensation and diazotization. This ligand is used to react with the copper(II) ion to form a copper complex and to determine small amounts of it. The prepared ligand and complex were characterized by UV-Vis, FT-IR, and 1H NMR spectra, and the molar electrical conductivity of the complex was also measured. Ion copper (II) was determined by a rapid, sensitive, simple and cheap spectrophotometric method, the copper compound has a molar absorbance of (1.764×105) L.mo1-1.cm-1, a Sandel sensitivity of (3.327×10-4) μg.cm-2, and a maximum absorbance of (417) nm, with a limit of detection of (0.0075) μg.mL-1 and a limit of quantitation of (0.025) μg.mL-1, the metal concentration obeys Beer's law within the range (0.05-1.25) μg.mL-1 with a correlation coefficient value of (0.9996) indicating the degree of linearity of the standard calibration for copper. In the complex, the molar ratio of the metal to the ligand was [1:2]. The results indicate that the complex has a high stability constant of 4.4546×10^8 (mol·L^-1), and these results show that this method was more sensitive, more precise, and more accurate, as evidenced by the calculated (Re, Erel, R.S.D) (%).

The photocatalytic degradation of the azo dye [3-((4-hydroxyphenyl) diazenyl)-4,5-dimethyl-1-phenyl-1,5-dihydro-2Hpyrrol-2-one][N1] was studied using aluminum oxide as a catalyst. The degradation process was performed at Rt, with a 125-watt mercury lamp as the external source. In this process, the impact of different amounts of aluminum oxide was tested, and the best degradation of the azo dye was achieved by using 0.12g of Al2O3. The effect of dye concentration was also studied in the presence of the optimal amount of Al2O3, with an optimal dye concentration of 20 ppm. For the entire process, the photodegradation efficiency was 82.78%.