HCoV-229E-IN-1 is a potent inhibitor of HCoV-229E replication, with an EC50 of 0.65 μM and 0.6 μM in MTS and CPE cells, respectively[1]. HCoV-229E-IN-1 (compound 5h) (0.01-100 μM) fully suppresses the capacity of HCoV-229E replication in a dose-dependent manner[1].HCoV-229E-IN-1 (12 μM) fully prevented the formation of dsRNA intermediates of CoV RNA synthesis[1]. [1]. Stevaert A, et, al. Betulonic Acid Derivatives Interfering with Human Coronavirus 229E Replication via the nsp15 Endoribonuclease. J Med Chem. 2021 May 13;64(9):5632-5644.