['CO', 'O=Cc1cc(-c2ccc3c(c2)OCO3)on1', 'COC=O', 'c1cc(-c2ccc3c(c2)OCO3)on1', 'COC(=O)c1ccon1', 'c1ccc2c(c1)OCO2']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cc(-c2ccc3c(c2)OCO3)on1.