['Clc1ccc(Cl)cc1', 'N#Cc1ccccc1/C=C/C(=O)NNC=O', 'Cc1ccccc1C#N', 'CC(=O)NNC(=O)c1cc(Cl)ccc1Cl']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(/C=C/c1ccccc1)NNC(=O)c1ccccc1.