Using COC(=O)c1ccc(OCCN2CCN(C(=O)OC(C)(C)C)CC2)c(C)c1 to produce COC(=O)c1ccc(OCCN2CCNCC2)c(C)c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.