Using CCCCc1nc(C(=O)OCC)c(Cl)n1C1CCc2cc(Br)ccc21 to produce CCCCc1nc(CO)c(Cl)n1C1CCc2cc(Br)ccc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.