Design, Synthesis, and Antibacterial, Antifungal, and Antioxidant Activities of New Four Membered Rings from Derivatives Containing a 4(3H)-Quinazolinone Moiety, Activities

Objective: The aim of this study is to produce novel 4(3H)-quinazolinone derivatives, analyze their efficacy as antibacterial and antifungal agents, and investigate their antioxidant abilities. Methods: New quinazolinone derivatives were synthesized by mixing Schiff bases with three different chemicals: phenyl isocyanate, 4-chlorophenyl isocyanate, and phenyl iso thiocyanate. This resulted in the formation of compounds (VIa–VIb), (VIIa–VIIb), and (VIIIa–VIIIb). The efficacy of these synthesized compounds against bacteria and fungi was evaluated. Subsequently, their antioxidant activity was assessed using the DPPH scavenging method. Results: FT-IR, ¹H NMR, and ¹³C NMR spectroscopy were used to investigate all the prepared derivatives. Compounds (VIIb), (VIIIa), and (VIIIb) exhibited good antioxidant activity when compared to ascorbic acid. Discussion: The presence of the quinazolinone nucleus in some compounds gives them good biological properties as antimicrobials and antioxidants. Conclusions: All the synthesized compounds were highly effective at killing fungi, especially Rhizopus microrhizosporium, and Candida. Most of them were also very effective at killing bacteria like E. coli, Bacillus cereus, and Pseudomonas aeruginosa. Although most of these compounds have relatively moderate effectiveness against Staphylococcus aureus, some of them contain good antioxidants, particularly compound (VIIIb).