Synthesis and Microbiological Activity of Some Substituted N-(2-hydroxy-4-nitrophenyl)benzamides and Phenylacetamides as Possible Metabolites of Antimicrobial Active Benzoxazoles

Authors: İLKAY YILDIZ ÖREN, ESİN AKI ŞENER, CENGİZ ERTAŞ, ÖZLEM TEMİZ ARPACI, İSMAİL YALÇIN, NURTEN ALTANLAR

Abstract: Some new antimicrobial active N-(2-hydroxy-4-nitrophenyl)- p-substituted benzamide and phenylacetamide analogues (I-II) were prepared by 2-step procedures from the corresponding carboxylic acids as possible metabolites of benzoxazoles. Their antimicrobial activities were tested against 3 Gram-positive and 2 Gram-negative bacteria with the fungus Candida albicans and were also compared with several control drugs. The compounds Ia, Id, IIa, and IIe were active at a MIC value of 12.5 \mu g/mL against the Gram-positive microorganism Bacillus subtilis. Most of the compounds exhibited antifungal activity at a MIC value of 12.5 \mu g/mL against C. albicans. On the other hand, the antimicrobial activity of some amide derivatives (Ia, Id, IIa-c) was also compared with their cyclic analogues, benzoxazole derivatives (III-IV). The compound Id significantly possessed 2 or 3 dilutions better antimicrobial activity than its heterocyclic derivative, 2-(p-t-butylphenyl)-5-nitrobenzoxazole, IIId, against Staphylococcus aureus, Streptococcus faecalis, Klebsiella pneumonia, and Escherichia coli.

Keywords: Antimicrobial activity, benzamide, benzoxazole, phenylacetamide

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