Using CC(=O)Nc1nc2c(ncn2COC(COC(=O)C(C)(C)C)COC(=O)C(C)(C)C)c(=O)[nH]1 to produce CC(C)(C)C(=O)OCC(COC(=O)C(C)(C)C)OCn1cnc2c(=O)[nH]c(N)nc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.