['CCN', 'O=CC1CCN(c2ncccc2[N+](=O)[O-])CC1', 'CC', 'NC(=O)C1CCN(c2ncccc2[N+](=O)[O-])CC1', 'O=[N+]([O-])c1cccnc1', 'CCNC(=O)C1CCNCC1', 'CCNC=O', 'O=[N+]([O-])c1cccnc1N1CCCCC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(N2CCCCC2)nc1.