Antibacterial activities of the synthetic 1,2,4-oxadiazole derivatives. The functionality within the green box was altered to generate all the synthetic compounds in this series, whereas Y was limited to the three entities that are indicated. The MIC values (in μg/mL) measured for S. aureus ATCC 29213, with the active compounds placed within the shaded blue area (MIC ≤ 8 μg/mL). Compounds in red font underwent in vivo evaluation. Properties of the lead compounds (57a, 57b, and 58b) have been described previously.9 Compound 57b is identical to compound 1 and will be referred to as such in the remainder of the text.