['Nc1ccccc1', 'O=C(O)/C=C/c1cncnc1', 'c1ccccc1', 'Nc1ncc(/C=C/C(=O)O)cn1', 'CC(=O)O', 'Cc1cnc(Nc2ccccc2)nc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(Nc2ncccn2)cc1.