['CC', 'CC1CCC2(CC1)NC(=O)N(CNCCC#N)C2=O', 'CCC#N', 'CCNCN1C(=O)NC2(CCC(C)CC2)C1=O', 'CCN(C)CCC#N', 'CC1CCC2(CC1)NC(=O)NC2=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C1NC(=O)C2(CCCCC2)N1.