['CC', 'O=[N+]([O-])c1ccc(N2CCCC(O)C2)c([N+](=O)[O-])c1', 'CCO', 'O=[N+]([O-])c1ccc(N2CCCCC2)c([N+](=O)[O-])c1', 'CCOC1CCCNC1', 'O=[N+]([O-])c1cccc([N+](=O)[O-])c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(N2CCCCC2)cc1.