Using CCOC(=O)CC1CCc2c(n(Cc3ccccc3)c3ccccc23)S1 to produce O=C(O)CC1CCc2c(n(Cc3ccccc3)c3ccccc23)S1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.