2.1.2. PASS Prediction

The 2D chemical structure of each target compound was input into the PASS application to obtain the probability of the corresponding compound to produce (Pa) or not (Pi) a certain biological effect. The application returns an array of Pa and Pi values for a very wide variety of pharmacological actions [49]. In the case of newly synthesized compounds **5**, **6**, **7a**, **7b**, **8a**, and **8b**, the 896 listed biological activities were filtered in relation to the antibacterial effect. The predicted probabilities Pa and Pi are presented in Table 1.



The two new α-acylamino ketones **7a** and **7b** were predicted to have very similar chances to produce antimycobacterial, antituberculosis, or anti-infective effects, and the corresponding values are significantly higher than those of the 1,3-oxazoles derivatives **8a** and **8b**. The Pa values reflect the likelihood of a certain effect to be produced, and not of its potency. Based on the Pa values, the addition of an aromatic fragment to *N*-acylated *L*-valine **5** has little impact on its predicted antimycobacterial and antituberculosis activities.
