['CO', 'O=CCOCCOc1ccccc1', 'COC(C)=O', 'OCCOc1ccccc1', 'COC(=O)CO', 'CCOc1ccccc1', 'Oc1ccccc1', 'CCOCC(=O)OC', 'c1ccccc1', 'COC(=O)COCCO']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.