['CO', 'O=CCCOCCOc1ccccc1', 'CCC(=O)OC', 'OCCOc1ccccc1', 'COC(=O)CCO', 'CCOc1ccccc1', 'Oc1ccccc1', 'CCOCCC(=O)OC', 'c1ccccc1', 'COC(=O)CCOCCO']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.