['CC1CCCNC1', 'CC(C)(C)c1noc(C=O)n1', 'CC1CCCN(C=O)C1', 'CC(C)(C)c1ncon1', 'CC(C)C', 'CC1CCCN(C(=O)c2ncno2)C1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(c1ncno1)N1CCCCC1.