Using O, CCOC(=O)c1cc2nc3c(cc2c2c1OC(C(=O)OCC)O2)C(c1ccc2c(c1)OCO2)OC3=O to produce O=C1OCc2c1nc1ccc3c(c1c2-c1ccc2c(c1)OCO2)OCO3, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.