Using CC1(C)C(=O)Nc2nc(-n3nc(Cc4ccccc4F)c4cc(F)ccc43)nc(O)c21, OCCC(F)(F)F to produce CC1(C)C(=O)Nc2nc(-n3nc(Cc4ccccc4F)c4cc(F)ccc43)nc(OCCC(F)(F)F)c21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.