['CC(C)C', 'O=S1(=O)CCCC(CS(=O)(=O)c2nc[nH]n2)C1', 'O=S1(=O)CCCCC1', 'CC(C)(C)c1nc(S(C)(=O)=O)n[nH]1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=S1(=O)CCCC(CS(=O)(=O)c2nc[nH]n2)C1.