A new hybrid approach and in vitro antimicrobial evaluation of novel 4(3H)-quinazolinones and thiazolidinone motifs

We have synthesized some novel fluorine containing 5-arylidene derivatives bearing different pharmacophores and heterocyclic systems like quinazolinone along with 4-thiazolidinone, which may act as potential antimicrobial agents. They have been synthesized by the Knoevenagel condensation of N-(2-(4-fluorophenyl)-4-oxothiazolidin-3-yl)-4-(4-oxo-2-p-tolylquinazolin-3(4H)-yl)benzamide with aromatic aldehydes to form N-(5-(aryl)-2-(4-fluorophenyl)-4-oxothiazolidin-3-yl)-4-(4-oxo-2-p-tolylquinazolin-3(4H)-yl)benzamides (6a–t). The products were characterized by IR, 1H, 13C and 19F NMR and mass spectral techniques. The synthesized compounds were evaluated for their in vitro antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus and Streptococcus pyogenes), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and fungi (Candida albicans, Aspergillus niger, and Aspergillus clavatus) using serial broth dilution method. Compounds 6b, 6d, 6i, 6j, 6k, 6n and 6s were the most noteworthy derivatives identified in the present study because of their remarkable in vitro antimicrobial potency.