['CC', 'Cn1cc(S(=O)(=O)NCC#N)c(=O)n(C)c1=O', 'CC#N', 'CCNS(=O)(=O)c1cn(C)c(=O)n(C)c1=O', 'CCNCC#N', 'Cn1cc([SH](=O)=O)c(=O)n(C)c1=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=c1cc[nH]c(=O)[nH]1.