Using CSc1ccc(-c2c(-c3ccc(F)cc3)sc(C(=O)O)c2CO)cc1 to produce CSc1ccc(-c2c(-c3ccc(F)cc3)sc3c2COC3=O)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.