['CC=O', 'N#CCc1ccc(NC(=O)CCN)cc1', 'CC(=O)NCCC=O', 'N#CCc1ccc(N)cc1', 'CC(N)=O', 'CCC(=O)Nc1ccc(CC#N)cc1', 'CC(=O)NCCC(N)=O', 'N#CCc1ccccc1', 'CC#N', 'CC(=O)NCCC(=O)Nc1ccccc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.