Using CCCCCCc1ccc(-c2ccc(-c3ccc(OCCC)s3)cc2)cc1 to produce CCCCCCc1ccc(-c2ccc(-c3ccc(O)s3)cc2)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.