Using O=C1CCC(=O)N1Br, CCOC(=O)N1CC2Cc3cc(C)sc3C2C1 to produce CCOC(=O)N1CC2Cc3c(sc(C)c3Br)C2C1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.