['CC(C)(C)C=O', 'NCCC(=O)NC1CC1c1ccccc1', 'NC1CC1c1ccccc1', 'CC(C)(C)C(=O)NCCC=O', 'CC(C)(C)C(N)=O', 'CCC(=O)NC1CC1c1ccccc1', 'c1ccc(C2CC2)cc1', 'CC(C)(C)C(=O)NCCC(N)=O', 'c1ccccc1', 'CC(C)(C)C(=O)NCCC(=O)NC1CC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(C2CC2)cc1.