['CO', 'Cc1cc(N)n(-c2nc3ccccc3s2)n1', 'COC', 'Nc1ccnn1-c1nc2ccccc2s1', 'COCc1cc(N)[nH]n1', 'c1ccc2scnc2c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2sc(-n3cccn3)nc2c1.