['CO', 'O=Cc1cc(-c2cc3ccccc3o2)on1', 'COC=O', 'c1ccc2oc(-c3ccno3)cc2c1', 'COC(=O)c1ccon1', 'c1ccc2occc2c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2oc(-c3ccno3)cc2c1.