['CC', 'CCNc1c([N+](=O)[O-])cc(C(=O)Cl)cc1[N+](=O)[O-]', 'CCNCC', 'O=C(Cl)c1cc([N+](=O)[O-])cc([N+](=O)[O-])c1', 'O=CCl', 'CCN(CC)c1c([N+](=O)[O-])cccc1[N+](=O)[O-]']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.