['CCCCCC=O', 'CCN(CC)[C@@H](N)C(Cl)(Cl)Cl', 'CCCCCC(N)=O', 'CCN(CC)CC(Cl)(Cl)Cl', 'CCNCC', 'CCCCCC(=O)NCC(Cl)(Cl)Cl', 'CC', 'CCCCCC(=O)N[C@H](NCC)C(Cl)(Cl)Cl']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is None.