Using COc1nc(OC)c(C(C)C)c(C(=O)c2cc(C)cc(C(OC)OC)c2)n1 to produce COc1nc(OC)c(C(C)C)c(C(=O)c2cc(C)cc(C=O)c2)n1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.