Using COC(=O)Cc1cc(Br)sc1-c1ccc(-c2sc(Br)cc2CC(=O)OC)s1 to produce O=C(O)Cc1cc(Br)sc1-c1ccc(-c2sc(Br)cc2CC(=O)O)s1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.