IC₅₀ values and percentage of inhibition at 50 μM concentration for M^PRO enzymatic activity of the selected compounds in the RapidFire High-Throughput Mass Spectrometry assay.

Compound	IC50 (μM)	Inhibition at 50 μM (%)
LASSBio-428 (10)	N.D.	−10.63
LASSBio-1600 (15)	N.D.	−16.29
LASSBio-1615 (11)	N.D.	7.53
LASSBio-1649 (13)	N.D.	−6.66
LASSBio-1652 (16)	N.D.	−12.83
LASSBio-1891 (14)	N.D.	−6.32
LASSBio-1945 (9)	15.97	68.26
LASSBio-1962 (8)	N.D.	0.77