['CO', 'N#CCN1CC(=N)N(c2ccccc2)C1=O', 'CC#N', 'COc1ccc(N2C(=N)CNC2=O)cc1', 'COc1ccccc1', 'N#CCN1CC(=N)NC1=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is N=C1CNC(=O)N1c1ccccc1.