['CCCCC(CC)CN', 'COc1ccc([N+](=O)[O-])c(C=O)c1', 'CO', 'CCCCC(CC)CNC(=O)c1ccccc1[N+](=O)[O-]', 'CCCCC(C)CC', 'COc1ccc([N+](=O)[O-])c(C(N)=O)c1', 'CCCCC(CC)CNC=O', 'COc1ccc([N+](=O)[O-])cc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.