Using O=C1OCCC1Br, CC(Oc1ccc(Oc2nc3ccc(Cl)cc3s2)cc1)C(=O)O to produce CC(Oc1ccc(Oc2nc3ccc(Cl)cc3s2)cc1)C(=O)OC1CCOC1=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.