['CO', 'COc1ccccc1-n1cc[nH]c1=S', 'COc1ccc(-n2cc[nH]c2=S)cc1', 'S=c1[nH]cc[nH]1', 'COc1cccc(OC)c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is S=c1[nH]ccn1-c1ccccc1.