['CO', 'CC(C)OCCOCC=O', 'COC(C)=O', 'CC(C)OCCO', 'COC(=O)CO', 'CCOC(C)C', 'CC(C)O', 'CCOCC(=O)OC', 'CCC', 'COC(=O)COCCO']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is None.