['CCC=O', 'Cc1ccc(-c2nc3sccn3c2N)cc1', 'CCC(N)=O', 'Cc1ccc(-c2cn3ccsc3n2)cc1', 'Cc1ccccc1', 'CCC(=O)Nc1cnc2sccn12']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(-c2cn3ccsc3n2)cc1.