['CCC=O', 'NCCNC(=O)c1ccc(N)cc1', 'NCCN', 'CCC(=O)Nc1ccc(C=O)cc1', 'CCN', 'CCC(=O)Nc1ccc(C(N)=O)cc1', 'CCC(N)=O', 'NCCNC(=O)c1ccccc1', 'NCCNC=O', 'CCC(=O)Nc1ccccc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.