Using CCOC(=O)c1c(NC(=O)C23CC4CC(CC(C4)C2)C3)sc2c1CCOC2 to produce O=C(O)c1c(NC(=O)C23CC4CC(CC(C4)C2)C3)sc2c1CCOC2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.