A Schiff base is a compound with the general structure R1R2C=NR’. They can be considered a subclass of imines. The term Schiff base is normally applied when these compounds are used as ligands to form coordination complexes with metal ions. Schiff bases can be synthesised from a primary aliphatic or aromatic amine and a carbonyl compound by nucleophilic addition forming a hemiaminal, followed by a dehydration to generate an imine. In other words, a Schiff base is a nitrogen analogue of a ketone or aldehyde where the carbonyl group has been replaced by azomethine or imine group. The imine group present in these compounds has been shown to be critical to their biological activities. Schiff bases have been frequently used in various fields such as medicine, pharmaceutical purposes due to their wide range of industrial applications. The unconventional methods of preparation of Schiff bases, compared with traditional methods, are more convenient, and reactions can be carried out in higher yield, shorter reaction time and milder conditions, without generation of pollution and safer to analyse.

The chemistry of pyridine and its derivatives is of considerable importance in the synthesis of intermediates leading to biologically active compounds and novel materials. Generally, derivatives of pyridine are stable and relatively unreactive but can be attacked by electrophiles at ring nitrogen and certain carbon atoms. Pyridines undergo radical substitution reactions preferentially at the 2-position. Simple pyridines and their benzo derivatives are weak bases that form salts with strong acids. Various Lewis acids form complexes with pyridine and its benzo derivatives. The quaternization of pyridine and its benzo derivatives using alkyl and acyl halides have been used as versatile synthetic intermediates to biologically active compounds as final products. Precursors to cyanine dyes have been prepared by means of the 1,4-addition of pyridines and quinolines to acrylamide. N-oxides, obtained by the oxidation of pyridine and its benzo analogues, are versatile intermediates in organic synthesis.

The N-phenylquinoneimine scaffold is a versatile synthetic platform that has gained significant attention in the field of drug discovery due to its structural diversity and capacity to interact with biologically relevant targets. This review explores established synthetic methodologies and highlights the significant biological activities exhibited by compounds derived from this scaffold, their implications for medicinal chemistry, and the development of novel therapeutics.

Phthalates and heavy metals are very toxic and are environmental pollutants. This study was aimed at determining the concentrations of phthalates and heavy metals in water from selected mechanic villages in two locations in Abeokuta (Idi-aba and Camp). The soil, plant and water samples were digested with concentrated HNO3 and analyzed for heavy metals (Cd, Mn, Fe, Cu and Pb) using Atomic Absorption Spectrometer. High Performance Liquid Chromatography- UV Spectrometer was used to quantify phthalates in the water samples which include Diethyl phthalates (DEP), Di-n-propyl phthalates (DPP), Di-n-butyl phthalates (DBP) and Diethylhexyl phthalates (DEHP) prior to which the water samples had been extracted with dichloromethane and cleaned-up into fractions. The result indicated the presence of all metals considered. The concentrations were compared with WHO (World Health Organization) standards. The result showed that Fe had the highest concentrations in all samples varied from 0.3 - 0.7 mg/L as against WHO standard (0.3 mg/L). The result obtained from the phthalates analysis showed that DEHP was present in all the samples obtained from the mechanic villages which is a common phthalate pollutant with concentration ranging between 0.02 to 3.53 ppb. The result obtained showed that in all the soil samples, Copper (Cu), Lead (Pb) and Cadmium (Cd) had the highest concentration ranging from 30.6 - 90.9, 111.5 - 137.6 and 7.7 - 8.0 mg/kg as against their WHO benchmarks (36, 85 and 0.8 mg/kg) respectively. The concentration of the heavy metals and phthalates showed that the activities of the mechanic villages have moderate effect on the soil, plant and water samples.

The crystal structure of the title compound is determined by X-ray diffraction studies. The crystal is triclinic, a = 3.9115(2) Å, b = 7.1327(4) Å, c = 19.8384(10) Å, α = 92.585(4) °, β = 92.771(4) °, γ = 98.729(4) °, space group P-1, V = 545.65(5) ų, Z = 2 for C₁₂H₇Cl₂NO, T = 150.0(2) K and ρ_calc = 1.534 g/cm³. The molecule is in the E isomeric form.

This study reports the synthesis and characterization of Schiff base ligands derived from 4-hydroxybenzaldehyde and L-glycine. The Schiff base was synthesized using a base catalyst (Potassium hydroxide). The derived Schiff base was reacted with metal salts (Cobalt (II) chloride pentahydrate and Copper (II) sulphate pentahydrate) to form Schiff base-metal complexes. The synthesized Schiff base, (E)-2-(4-hydroxybenzylideneamino) acetic acid and its metal complexes were characterized using Fourier Transform-Infrared (FT-IR) spectroscopy and solubility in selected solvents. The antimicrobial activity of the synthesized complexes was evaluated against strains of Staphylococcus aureus, Escherichia coli using standard agar diffusion method. The result demonstrated that the metal complexes exhibited enhanced antimicrobial activity compared to the Schiff base. The result shows the potential of the complexes as antimicrobial agents, highlighting the importance of metal-amino acid interactions in enhancing biological activity.