Using Nc1c2c(nc3ccccc13)CCC(CCC1CCN(Cc3ccccc3)CC1)C2=O to produce Nc1c2c(nc3ccccc13)CCC(CCC1CCN(Cc3ccccc3)CC1)C2O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.