['C=C(C)C', 'Cc1cc(=O)oc2cc(O)c(CCC(=O)O)cc12', 'C=C(C)CO', 'Cc1cc(=O)oc2ccc(CCC(=O)O)cc12', 'CCC(=O)O', 'C=C(C)COc1ccc2c(C)cc(=O)oc2c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=c1ccc2ccccc2o1.