['CC(C)c1nnc(N)s1', 'CC(C)(C)C(=O)NCC=O', 'CC(C)(C)C=O', 'CC(C)c1nnc(NC(=O)CN)s1', 'CC(C)(C)C(N)=O', 'CC(=O)Nc1nnc(C(C)C)s1', 'CC(C)c1nncs1', 'CC(C)(C)C(=O)NCC(N)=O', 'CCC', 'CC(C)(C)C(=O)NCC(=O)Nc1nncs1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1nncs1.