SARS-CoV-2(67) COVID-19(52) inhibitor(42) protease(34) inhibitors(29) inhibit(28) Antiviral(27) coronavirus(26) antiviral activity(25) Compound(24) Replication(23) derivative(22) the SARS-CoV-2(20) SARS-CoV-2.(18) demonstrated(17) M pro(17) exhibited(16) in vitro(16) Antiviral agents(16) cytotoxicity(16) evaluated(15) Protease inhibitor(15) acute respiratory syndrome(15) acute respiratory syndrome coronavirus(15) Protein(14) active site(14) crystal structure(14) enzyme(13) effective(13) X-ray(13)