['CC=O', 'O=C(C[C@@H]1CCCC[C@H]1O)N1CCCNCC1', 'O=CC[C@@H]1CCCC[C@H]1O', 'CC(=O)N1CCCNCC1', 'OC1CCCCC1', 'CC(=O)N1CCCN(C(C)=O)CC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(CC1CCCCC1)N1CCCNCC1.