Using CCOC(=O)CN1C(=O)C(Cl)(Cl)CCc2ccccc21, C1COCCN1 to produce CCOC(=O)CN1C(=O)C(=O)CCc2ccccc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.