['CC', 'Nc1cc(-c2ccc(O)cc2)n[nH]c1=O', 'CCO', 'Nc1cc(-c2ccccc2)n[nH]c1=O', 'Nc1ccn[nH]c1=O', 'CCOc1ccccc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=c1ccc(-c2ccccc2)n[nH]1.