Scheme 1. Schematic representation of the main classes of covalent inhibitors of CoVs Mpro so far reported. The reactive center on the warhead is marked with an asterisk. R emerging from P2 residue represents a lipophilic group of moderate size. The tail region is a highly variable portion in term of size and shape and involved other Mpro sub-pockets (i.e. S3 and S4) not represented in the scheme.
