['Cn1nncc1[SH](=O)=O', 'FC(F)(F)c1cccc2c1CCN2', 'FC(F)F', 'Cn1nncc1S(=O)(=O)N1CCc2ccccc21']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=S(=O)(c1cnn[nH]1)N1CCc2ccccc21.