['CCNCC#N', 'Cc1ccc(C=O)cc1[N+](=O)[O-]', 'CC', 'Cc1ccc(C(=O)NCC#N)cc1[N+](=O)[O-]', 'CC#N', 'CCNC(=O)c1ccc(C)c([N+](=O)[O-])c1', 'CCN(C=O)CC#N', 'Cc1ccccc1[N+](=O)[O-]']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.