Using COC(=O)c1ccc(S(C)(=O)=O)cc1OCCNC(=O)OC(C)(C)C to produce CC(C)(C)OC(=O)NCCOc1cc(S(C)(=O)=O)ccc1C(=O)O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.