Using Cc1cn2c3ccc(Br)cc3c3cc(O)cc(c1=O)c32, CC(C)(C)OC(=O)CBr to produce Cc1cn2c3ccc(Br)cc3c3cc(OCC(=O)OC(C)(C)C)cc(c1=O)c32, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.