['CC(=O)O', 'Cc1ccc(-c2cnc(S)[nH]2)cc1', 'O=C(O)CS', 'Cc1ccc(-c2cnc[nH]2)cc1', 'Cc1ccccc1', 'O=C(O)CSc1ncc[nH]1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(-c2cnc[nH]2)cc1.