Using CC(C)(C)OC(=O)CCn1c2ccccc2c2c3c(c4c5ccccc5[nH]c4c21)C(=O)NC3 to produce O=C(O)CCn1c2ccccc2c2c3c(c4c5ccccc5[nH]c4c21)C(=O)NC3, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.