Using O=C(O)C[C@H](Cc1cc(Br)c2[nH]ncc2c1CO)C(=O)O to produce O=C(O)C[C@@H]1Cc2cc(Br)c3[nH]ncc3c2COC1=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.