Using CCOC(=O)Cc1csc(S)n1, CC(C)(C)OC(=O)C(C)(C)Br to produce CCOC(=O)Cc1csc(SC(C)(C)C(=O)OC(C)(C)C)n1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.