Using CC(C)(C)OC(=O)OC(=O)OC(C)(C)C, Nc1nccs1 to produce CC(C)(C)OC(=O)N(C(=O)OC(C)(C)C)c1nccs1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.