The isoxazol-5(4H)-ones they stand out in organic synthesis for demonstrating antibiotics and analgesics[1]. The microdilution method has the advantage of sensitivity, reproducibility and low cost[2]. The use of MAI.Cl- acid catalyst was tested in the reaction, and various aromatic aldehydes to form 3,4-disubstituted isoxazol-5(4H)-one derivatives (Scheme 1). The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the compounds against Staphylococcus epidermidis (ATCC 12228) and Escherichia coli (ATCC 25312) bacteria were evaluated. Density Functional Theory (DFT) method at the theory level M062X/6-311++G(d,p) was used to calculate a set of molecular properties of all studied compounds. Principal Component Analysis (PCA) of the molecular descriptors discriminated the compounds into active and inactive. With application of the PCA method, the active molecules in blue were obtained, being those molecules that presented moderate to good antibacterial activity against the strains. With a MIC between 250 - 500 µg/ml for E. coli and < 15.62 - 250 µg/ml for S. epidermidis.