Using O=C1CCC(=O)N1Br, CC(=O)Oc1ccc2c(c1)C(=O)CC2c1ccccc1 to produce CC(=O)Oc1ccc2c(c1)C(=O)C(Br)=C2c1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.