['CC(N)C(=O)NC(C)(C)C', 'Cc1c(C=O)oc2c1C(=O)CC(C)(C)C2', 'CC(C)(C)N', 'Cc1c(C(=O)NC(C)C=O)oc2c1C(=O)CC(C)(C)C2', 'CCC(=O)NC(C)(C)C', 'Cc1c(C(N)=O)oc2c1C(=O)CC(C)(C)C2', 'CC(C)C', 'Cc1c(C(=O)NC(C)C(N)=O)oc2c1C(=O)CC(C)(C)C2', 'CC(NC=O)C(=O)NC(C)(C)C', 'Cc1coc2c1C(=O)CC(C)(C)C2']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C1CCCc2occc21.