['CS(=O)(=O)C1(C=O)CC1', 'Cn1nccc1C1=CCNCC1', 'CS(=O)(=O)C1CC1', 'Cn1nccc1C1=CCN(C=O)CC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(C1CC1)N1CC=C(c2ccn[nH]2)CC1.