CC(C)C[C@H](NC(=O)C(C)(C)NC(=O)OC(C)(C)C)C(=O)N[C@@H](CN1CCCC1=O)C1=CC(=O)N(Cc2ccccc2)C1=O
CC(C)C[C@H](NC(=O)CNC(=O)OC(C)(C)C)C(=O)N[C@@H](C[C@@H]1CCNC1=O)C1=CC(=O)N(Cc2ccccc2)C1=O
CC(C)C[C@H](NC(=O)CNC(=O)OC(C)(C)C)C(=O)N[C@H](C=C(C#N)C#N)CN1CCCC1=O
Design based on PDB 6y2f and comments made by P.W. Kenny (SARS-CoV-2 main protease design themes based on 6y2f X-ray crystal structure) Maleimide warhead instead of alpha keto amide/ aldehyde.