['CO', 'CC(C)N(CCC=O)Cc1ccc([N+](=O)[O-])cc1', 'CCC(=O)OC', 'CC(C)NCc1ccc([N+](=O)[O-])cc1', 'Cc1ccc([N+](=O)[O-])cc1', 'COC(=O)CCNC(C)C', 'CCC', 'COC(=O)CCNCc1ccc([N+](=O)[O-])cc1', 'O=[N+]([O-])c1ccccc1', 'COC(=O)CCN(C)C(C)C']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.