Using CC(C)(C)C(=O)OCBr, O=C([O-])C1C(=O)CC2CC(=O)N21 to produce CC(C)(C)C(=O)OCOC(=O)C1C(=O)CC2CC(=O)N21, please predict the solvent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.