Remarkably, the highest T m was observed with the most efficient inhibitor 13 (IC50 0.6 ± 0.1 μM) that stabilizes SARS-CoV nsp14 against thermal denaturation with a ΔT m +10.8 °C and exhibits notable binding affinity (apparent KD 1.3 ± 0.87 μM), as deduced from TSA performed with increasing concentration of compound 13.