['O=CC[C@H]1CCOC1', 'CS(=O)(=O)c1ccc2c(c1)CCCN2', 'C1CCOC1', 'CC(=O)N1CCCc2cc(S(C)(=O)=O)ccc21']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(C[C@H]1CCOC1)N1CCCc2ccccc21.