['CO', 'O=C(O)/C=C/c1ccnc(-c2ccccc2)n1', 'CC(=O)O', 'COc1ccc(-c2nccc(C)n2)cc1', 'COc1ccccc1', 'O=C(O)/C=C/c1ccncn1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(-c2ncccn2)cc1.