Using O=Cc1c(Br)nc(C2OCCO2)n1Cc1cc2c(cc1Cl)OCO2, CCOC(=O)CCCCCS to produce CCOC(=O)CCCCCSc1nc(C2OCCO2)n(Cc2cc3c(cc2Cl)OCO3)c1C=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.