['CO', 'COc1ccc(OC)c(C(=O)NO)c1', 'COc1ccc(C(=O)NO)cc1OC', 'COc1ccc(C(=O)NO)c(OC)c1', 'O=CNO', 'COc1ccc(OC)c(OC)c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.