['CCC', 'CCc1cnn(-c2nc(C)cc(C)n2)c1N', 'CC', 'CCCc1cc(N)n(-c2nc(C)cc(C)n2)n1', 'Cc1cc(C)ncn1', 'CCCc1n[nH]c(N)c1CC']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cnc(-n2cccn2)nc1.