Using COC(=O)CCCSc1nc2ccccn2c1Cc1csc2ccc(Cl)cc12 to produce O=C(O)CCCSc1nc2ccccn2c1Cc1csc2ccc(Cl)cc12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.