['N#CCCNCCC#N', 'CN1C(=C(C#N)C(=O)CCC=O)N(C)c2ccccc21', 'CCC#N', 'CN1C(=C(C#N)C(=O)CCC(=O)NCCC#N)N(C)c2ccccc21']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C=C1Nc2ccccc2N1.