Using COS(=O)(=O)OC, O=C(O)c1ccc(Cl)cc1Nc1cccc(Br)c1 to produce Cn1c2cc(Cl)ccc2c(=O)c2c(Br)cccc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.