Using NCc1cnc(Nc2cccc(Cl)c2)nc1C(F)(F)F, O=C(O)C1CCOCC1 to produce O=C(NCc1cnc(Nc2cccc(Cl)c2)nc1C(F)(F)F)C1CCOCC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.