Using C=CCNc1c(C(=O)OCC)cnc2cn[nH]c12, COC(C)(C)OC to produce C=CCNc1c(C(=O)OCC)cnc2cn(C(C)(C)OC)nc12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.