['CO', 'CCN(Cc1cccc([N+](=O)[O-])c1)CC(C)C#N', 'CC', 'COc1ccc(CNCC(C)C#N)cc1[N+](=O)[O-]', 'CCNCC(C)C#N', 'COc1ccc(C)cc1[N+](=O)[O-]', 'CC(C)C#N', 'CCNCc1ccc(OC)c([N+](=O)[O-])c1', 'CCN(C)CC(C)C#N', 'COc1ccccc1[N+](=O)[O-]']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.