Synthesis, characterization, and antimicrobial evaluation of oxadiazole congeners

• Published in: Molecules (Basel, Switzerland) Vol. 16; no. 6; pp. 4339 - 4347
• Main Authors: Sadek, Bassem, Fahelelbom, Khairi Mustafa Salem
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 25-05-2011; MDPI
• Subjects: 1,3-oxazole; 1,3-thiazole; Anti-Bacterial Agents - chemical synthesis; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; antibacterial; antifungal; Antifungal Agents - chemical synthesis; Antifungal Agents - chemistry; Antifungal Agents - pharmacology; Antimicrobial agents; Aspergillus niger - drug effects; E coli; Escherichia coli - drug effects; Methicillin-Resistant Staphylococcus aureus - drug effects; Microbial Sensitivity Tests; oxadiazole congeners; Oxadiazoles - chemical synthesis; Oxadiazoles - chemistry; Oxadiazoles - pharmacology; Potash; Potassium; Staphylococcus infections; tetrazole
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules16064339

A series of 1,3-oxazole, 1,3-thiazole, isomeric 1,2,4-oxadiazole, 1,3,4-oxadiazole, and 1,2,3,4-tetrazole heterocycles was synthesized. All the compounds shared as a common feature the presence of a 4-hydroxyphenyl substituent. The structures of the synthesized compounds were confirmed by MS, ¹H-NMR, and elemental analysis. In vitro antimicrobial activity for all the newly synthesized compounds at concentrations of 200-25 μg/mL was evaluated against Gram+ve organisms such as methicillin-resistant Staphylococcus aureus (MRSA), Gram-ve organisms such as Escherichia coli (E. coli), and the fungal strain Aspergillus niger (A. niger) by the cup plate method. Ofloxacin and ketoconazole (10 μg/mL) were used as reference standards for antibacterial and antifungal activity, respectively. Compounds 15, 16, and 20 showed notable antibacterial and antifungal activities at higher concentrations (200 μg/mL), whereas 17-19 were found to display significant antibacterial or antifungal activity (25-50 μg/mL) against the Gram+ve, Gram-ve bacteria, or fungal cells used in the present study.