Diamond et al. reported CID 16725315 (21) and CID 23631927 (22; Figure 9) as viral entry inhibitors of SARS‐CoV in a cathepsin L inhibition assay. Compound 21 could block cathepsin L with an IC50 value of 6.9 nM, while 22 showed slightly weaker potency (IC50, 56 nM). Compound 22 was also found to inhibit Ebola virus infection (EC50, 193 nM) of human embryonic kidney 293T cells. This compound did not show any sign of toxicity to human aortic endothelial cells up to 100 µM. This data offers a new promising point for the treatment of SARS and Ebola virus infections. 116