['CO', 'CCCc1c(N)n[nH]c1-c1ccccc1', 'CCC', 'COc1ccc(-c2cc(N)n[nH]2)cc1', 'COc1ccccc1', 'CCCc1c[nH]nc1N']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(-c2ccn[nH]2)cc1.