Synthesis and Antimicrobial Evaluation of Quinazolinone Peptide Derivatives

Abstract

Objective: The increased microbial resistance against commercially available drugs initiated the development of novel and safe antimicrobial agents in last few decades. In this view, a series of amino acid/dipeptide derivatives of quinazolin-3(4H)-one was synthesized and was evaluated for their antimicrobial potential.Method: Synthesis of amino acid/peptide derivatives were carried out by coupling 5-(2-(2-chlorophenyl)-4-oxoquinazolin-3(4H)-yl)-2-hydroxy benzoic acid with amino acid/dipeptide methyl esters in the presence of dicyclohexylcarbodiimide and N-methylmorpholine. The chemical structures of synthesized compounds were characterized by 1 H nuclear magnetic resonance and infrared spectroscopy and were screened for antibacterial activity by disc diffusion method.Results: All the synthesized derivatives exhibited moderate to significant antibacterial activity against both Gram-positive and Gram-negative bacteria. The potency of compound 5d was comparable to standard drug ciprofloxacin in all the strains of bacteria used. The compound 5a was found to be more active against Streptococcus pyogenes and Staphylococcus aureus while compound 5c against Pseudomonas aeruginosa and Escherichia coli. Conclusion:Peptide derivatives of quinazolinone are promising antimicrobial agent and can be used for the synthesis of other novel compounds.

Design, Synthesis, Characterization and Biological Evaluation of Para-Amino Salicylic Acid (PAS) Analogues: An Approach to Repurpose

“…With the help of DPPH free radical scavenging method, the scavenging ability of the synthesized derivatives was checked against the reference drug BHA. The bleaching of the purple colour of the methanol solution of DPPH indicated the hydrogen atom or electron-donating abilities of the compounds 25 The table shows the percentage inhibition values of the synthesized ester derivatives of Para-amino salicylic acid, Standard (BHA) and PAS against DPPH (1,1-diphenyl-2-picryl-hydroxyl) at different concentrations (2µg/ml, 4µg/ml, 6µg/ml, 8 µg/ml, 10 µg/ml) and IC50 values calculated graphically by following linear regression plots.…”

The SYNTHESIS, SCREENING OF NOVEL 1-SUBSTITUTED-3-(4-OXO-2-PHENYLQUINAZOLIN-3(4H)-YL) UREA AND THIOUREA ANALOGUES AS POTENT ANTIBACTERIALS

“…The compounds screened for their antimicrobial potential against S. pyogenes, S. aureus, P. aeruginosa, and E. coli. All the derivatives have shown promising antimicrobial activity, but the compounds with isopropyl and indole derivatives were having more promising and reproducible effect [11][12][13].…”