Small molecule entry inhibitors, on the other hand, are reported to target the RBD. Compared to peptides, proteins, and biologics, small molecules have several advantages due to lower production costs, improved pharmacokinetics, stability, and dosage accuracy. Sarafianos et al. identified the oxazole‐carboxamide derivative SSAA09E2 (1; Figure 4) as an entry inhibitor against SARS‐CoV‐1 by screening a chemical library composed of 3000 compounds. 47  This inhibitor directly blocks ACE2 recognition by interfering with the RBD with an EC50 value of 3.1 µM and a 50% cytotoxic concentration (CC50) value of greater than 100 µM, not affecting ACE2 expression levels. 48