Using O=C(O)CCN1C(=O)C=CC1=O, CC(C)(Br)C(=O)OCCO to produce CC(C)(Br)C(=O)OCCOC(=O)CCN1C(=O)C=CC1=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.