['CCC=O', 'COc1ccc(S(=O)(=O)NCCN)cc1', 'CO', 'CCC(=O)NCCNS(=O)(=O)c1ccccc1', 'CCC(N)=O', 'CCNS(=O)(=O)c1ccc(OC)cc1', 'CCNC(=O)CC', 'COc1ccc(S(N)(=O)=O)cc1', 'CCC(=O)NCCN', 'COc1ccc([SH](=O)=O)cc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.