['C=CCC', 'O=C(O)c1ccc(CO)o1', 'C=CCCO', 'Cc1ccc(C(=O)O)o1', 'O=CO', 'C=CCCOCc1ccco1', 'C=CCCOC', 'O=C(O)c1ccco1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccoc1.