Using O=C(NCCc1ccccn1)c1cnc2cc3c(cc2c1Cl)OCO3, S to produce O=C(NCCc1ccccn1)c1cnc2cc3c(cc2c1S)OCO3, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.