['CC(C)CN', 'COCCOCCC=O', 'CO', 'CCOCCC(=O)NCC(C)C', 'CCOC', 'CC(C)CNC(=O)CCO', 'COCCO', 'CCC(=O)NCC(C)C', 'CC(C)C', 'COCCOCCC(N)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is None.