['CC(C)C', 'CC(C)CNCc1ccc(C(N)=O)cc1[N+](=O)[O-]', 'CC(C)CNCC(C)C', 'Cc1ccc(C(N)=O)cc1[N+](=O)[O-]', 'NC=O', 'CC(C)CN(Cc1ccccc1[N+](=O)[O-])CC(C)C', 'CC(C)CN(C)CC(C)C', 'NC(=O)c1cccc([N+](=O)[O-])c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.