['CC(=O)N[C@H](C=O)C(C)C', 'CCCCCc1nnc(N)s1', 'CC=O', 'CCCCCc1nnc(NC(=O)[C@@H](N)C(C)C)s1', 'CC(N)=O', 'CCCCCc1nnc(NC(=O)CC(C)C)s1', 'CCCCCc1nncs1', 'CC(=O)N[C@H](C(N)=O)C(C)C', 'CCCCC', 'CC(=O)N[C@H](C(=O)Nc1nncs1)C(C)C']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1nncs1.