['CCO', 'CCN(CC)S(=O)(=O)CC=O', 'CC', 'CCN(CC)S(=O)(=O)CC(=O)O', 'CCNS(=O)(=O)CC(=O)OCC', 'CCNCC', 'CCOC(=O)C[SH](=O)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is None.