['O=CC1CC(F)(F)C1', 'COC1CNCCC1C', 'CO', 'CC1CCN(C(=O)C2CC(F)(F)C2)CC1', 'FC1(F)CCC1', 'COC1CN(C=O)CCC1C']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(C1CCC1)N1CCCCC1.