['CO', 'CCCCC(=O)C(C#N)c1nc(-c2ccccc2)cs1', 'CCCCC(=O)CC#N', 'COc1ccc(-c2cscn2)cc1', 'COc1ccccc1', 'CCCCC(=O)C(C#N)c1nccs1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(-c2cscn2)cc1.