Using NCCO, CCOC(=O)c1cccc(-c2ccn3c(-c4cccc(-n5cccn5)c4)cnc3c2)c1 to produce O=C(NCCO)c1cccc(-c2ccn3c(-c4cccc(-n5cccn5)c4)cnc3c2)c1, please predict the solvent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.