['CCCCC=O', 'CC(C)CC(=O)Nc1ccc(N)cc1', 'CC(C)CC=O', 'CCCCC(=O)Nc1ccc(N)cc1', 'CCCCC(N)=O', 'CC(C)CC(=O)Nc1ccccc1', 'CC(C)CC(N)=O', 'CCCCC(=O)Nc1ccccc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.