['Cc1sc(N)c(C#N)c1C', 'CC(C)(C=O)S(=O)(=O)C1CC1', 'Cc1scc(C#N)c1C', 'CC(C)(C(N)=O)S(=O)(=O)C1CC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(CS(=O)(=O)C1CC1)Nc1cccs1.