In this investigation, it was of interest to synthesize novel series of peptide analogs of 3-bromocoumarins and 2-methylimidazoles. Substituted coumarinyl-oxyacetic acids 1, 2 were synthesized by alkylation of corresponding hydroxycoumarins with chloroacetic acid. The imidazolyl derivatives 13, 14 were prepared by interaction of 2-methylimidazole with substituted/unsubstituted anthranilic acids. Coupling of compounds 1, 2, 13 and 14 with different amino acid methyl ester hydrochlorides, dipeptide, tripeptide and tetrapeptide methyl esters afforded novel coumarino/imidazolopeptide derivatives 3-10 and 15-22. Selected peptide ester derivatives were further hydrolyzed by using lithium hydroxide to afford corresponding acid derivatives 11, 12 and 23, 24. The antibacterial and antifungal effects of synthesized peptide derivatives were studied against eight pathogenic microbes. Among the tested compounds, 19, 22 and its hydrolyzed analog 24 exhibited good antimicrobial activity against Pseudomonas aeruginosa, Klebsiella pneumoniae, Trichophyton mentagrophytes and Microsporum audouinii, and compounds 8, 10 and 12 displayed good antifungal activity against Candida albicans with minimum inhibitory concentration of 6.25 μg/ml.
Key words: Bromocoumarin, methylimidazole, anthranilic acid, peptide coupling, antibacterial activity, antifungal activity.
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