Using C[C@@H]1C(=O)NN=C2COc3ccc(C4=CCN(C(=O)OC(C)(C)C)C[C@@H]4C)cc3N21 to produce C[C@@H]1C(=O)NN=C2COc3ccc([C@@H]4CCN(C(=O)OC(C)(C)C)C[C@@H]4C)cc3N21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.