['CO', 'COc1cccc(-c2[nH]nc(N)c2C)c1', 'COc1ccc(-c2[nH]nc(N)c2C)cc1', 'Cc1c[nH]nc1N', 'COc1ccccc1OC']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(-c2ccn[nH]2)cc1.