['NC=O', 'CC(C)c1ccc(S(N)(=O)=O)cc1', 'NC(N)=O', 'CC(C)c1ccc([SH](=O)=O)cc1', 'CCC', 'NC(=O)NS(=O)(=O)c1ccccc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.