['CCC(C)C', 'Nc1ncc([N+](=O)[O-])c(NC2CC2)n1', 'CC(C)CCN', 'O=[N+]([O-])c1cncnc1NC1CC1', 'NC1CC1', 'CC(C)CCNc1ncc([N+](=O)[O-])cn1', 'C1CC1', 'CC(C)CCNc1ncc([N+](=O)[O-])c(N)n1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cc(NC2CC2)ncn1.