Using C=CCN1C(=O)CCC(N2C(=O)c3ccccc3C2=O)C(=O)N1CC(=O)OC(C)(C)C to produce CCCN1C(=O)CCC(N2C(=O)c3ccccc3C2=O)C(=O)N1CC(=O)OC(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.