Using O=C1CCC(=O)N1Br, CCOC(=O)N1CCC2Cc3sc(C)cc3C2C1 to produce CCOC(=O)N1CCC2Cc3sc(C)c(Br)c3C2C1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.