Using COC(=O)[C@@H]1CCCN1, O=C(O)[C@@H]1CCCN1C(=O)CN1CCCC1=O to produce COC(=O)[C@@H]1CCCN1C(=O)[C@@H]1CCCN1C(=O)CN1CCCC1=O, please predict the solvent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.