Using CCOC(=O)Cc1ccc2c(c1)sc1nc(=O)cc(-c3ccccc3)n12 to produce O=C(O)Cc1ccc2c(c1)sc1nc(=O)cc(-c3ccccc3)n12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.