Synthesis, modification and docking studies of 5-sulfonyl isatin derivatives as SARS-CoV 3C-like protease inhibitors

Abstract

The Severe Acute Respiratory Syndrome (SARS) is a serious life-threatening and strikingly mortal respiratory illness caused by SARS-CoV. SARS-CoV which contains a chymotrypsin-like main protease analogous to that of the main picornavirus protease, 3CLpro. 3CLpro plays a pivotal role in the viral replication cycle and is a potential target for SARS inhibitor development. A series of isatin derivatives as possible SARS-CoV 3CLpro inhibitors was designed, synthesized, and evaluated by in vitro protease assay using fluorogenic substrate peptide, in which several showed potent inhibition against the 3CLpro. Structure–activity relationship was analyzed, and possible binding interaction modes were proposed by molecular docking studies. Among all compounds, 8k1 showed most potent inhibitory activity against 3CLpro (IC50=1.04μM). These results indicated that these inhibitors could be potentially developed into anti-SARS drugs.