['CNC(C)C(C)(C)C', 'CS(=O)(=O)c1cc(C=O)cc([N+](=O)[O-])c1', 'CCC(C)(C)C', 'CNC(=O)c1cc([N+](=O)[O-])cc(S(C)(=O)=O)c1', 'CC(N(C)C=O)C(C)(C)C', 'CS(=O)(=O)c1cccc([N+](=O)[O-])c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.