Spectroscopic studies and biological evaluation of some transition metal complexes of Schiff-base ligands derived from 5-arylazo-salicylaldehyde and thiosemicarbazide

Novel Schiff base scaffolds derived from 4-aminoantipyrine and 2-hydroxy-3-methoxy-5-(phenyldiazenyl)benzaldehyde: Synthesis, antibacterial, antioxidant, and anti-inflammatory

The synthesis of four new azo Schiff base ligands from 2-hydroxy-3-methoxy-5-(phenyldiazenyl)benzaldehyde and 4-aminoantipyrine is described in this study. The molecular structures of all the scaffolds were confirmed using NMR spectroscopies such as ¹ H and ¹³ C, as well as FT-IR and Mass spectroscopy. After successful synthesis and characterization of all the ligands, their In-vitro antibacterial, antioxidant and anti-inflammatory activities were carried out by using standard protocols. Results revealed that all the four ligands (L1-L4) possessed excellent biological potency. This article is protected by copyright. All rights reserved.

Novel C-2 Symmetric Molecules as α-Glucosidase and α-Amylase Inhibitors: Design, Synthesis, Kinetic Evaluation, Molecular Docking and Pharmacokinetics

A series of symmetrical salicylaldehyde-bishydrazine azo molecules, 5a–5h, have been synthesized, characterized by ¹H-NMR and ¹³C-NMR, and evaluated for their in vitro α-glucosidase and α-amylase inhibitory activities. All the synthesized compounds efficiently inhibited both enzymes. Compound 5g was the most potent derivative in the series, and powerfully inhibited both α-glucosidase and α-amylase. The IC₅₀ of 5g against α-glucosidase was 0.35917 ± 0.0189 µM (standard acarbose IC₅₀ = 6.109 ± 0.329 µM), and the IC₅₀ value of 5g against α-amylase was 0.4379 ± 0.0423 µM (standard acarbose IC₅₀ = 33.178 ± 2.392 µM). The Lineweaver-Burk plot indicated that compound 5g is a competitive inhibitor of α-glucosidase. The binding interactions of the most active analogues were confirmed through molecular docking studies. Docking studies showed that 5g interacts with the residues Trp690, Asp548, Arg425, and Glu426, which form hydrogen bonds to 5g with distances of 2.05, 2.20, 2.10 and 2.18 Å, respectively. All compounds showed high mutagenic and tumorigenic behaviors, and only 5e showed irritant properties. In addition, all the derivatives showed good antioxidant activities. The pharmacokinetic evaluation also revealed promising results

Structural, spectral and biological studies of binuclear tetradentate metal complexes of N3O Schiff base ligand synthesized from 4,6-diacetylresorcinol and diethylenetriamine

The binuclear Schiff base, H2L, ligand was synthesized by reaction of 4,6-diacetylresorcinol with diethylenetriamine in the molar ratio 1:2. The coordination behavior of the H2L towards Cu(II), Ni(II), Co(II), Zn(II), Fe(III), Cr(III), VO(IV) and UO2(VI) ions has been investigated. The elemental analyses, magnetic moments, thermal studies and IR, electronic, 1H NMR, ESR and mass spectra were used to characterize the isolated ligand and its metal complexes. The ligand acts as dibasic with two N3O-tetradentate sites and can coordinate with two metal ions to form binuclear complexes. The bonding sites are the nitrogen atoms of the azomethine and amine groups and the oxygen atoms of the phenolic groups. The metal complexes exhibit either square planar, tetrahedral, square pyramid or octahedral structures. The Schiff base ligand and its metal complexes were tested against four pathogenic bacteria (Staphylococcus aureus and Streptococcus pyogenes) as Gram-positive bacteria, and (Pseudomonas fluorescens and Pseudomonas phaseolicola) as Gram-negative bacteria and two pathogenic fungi (Fusarium oxysporum and Aspergillus fumigatus) to assess their antimicrobial properties. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.