['CC(C)(N)C(N)=O', 'CC(C)(C)c1ncc(C=O)s1', 'CC(C)C(N)=O', 'CC(C)(C)c1ncc(C(N)=O)s1', 'CC(C)(NC=O)C(N)=O', 'CC(C)(C)c1nccs1', 'CC(C)C', 'CC(C)(NC(=O)c1cncs1)C(N)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cscn1.