['CC', 'Cc1cccc([N+](=O)[O-])c1S(=O)(=O)NCC#N', 'CC#N', 'CCNS(=O)(=O)c1c(C)cccc1[N+](=O)[O-]', 'CCNCC#N', 'Cc1cccc([N+](=O)[O-])c1[SH](=O)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.