['CNC', 'O=[N+]([O-])c1ccc2cnn(CN3CCc4cc([SH](=O)=O)ccc43)c2c1', 'O=[N+]([O-])c1ccc2cn[nH]c2c1', 'CN1CCc2cc(S(=O)(=O)N(C)C)ccc21']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2c(c1)CCN2Cn1ncc2ccccc21.