['CCO', 'C[C@@H](C=O)Oc1cccc2c(=O)[nH]ccc12', 'CC', 'C[C@H](Oc1cccc2c(=O)[nH]ccc12)C(=O)O', 'CCOC(=O)CC', 'O=c1[nH]ccc2c(O)cccc12', 'CCOC(=O)[C@H](C)O', 'O=c1[nH]ccc2ccccc12']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=c1[nH]ccc2ccccc12.