['CC(=O)NCCN', 'CCCc1ccc(C=O)cc1', 'CC=O', 'CCCc1ccc(C(=O)NCCN)cc1', 'CCNC(C)=O', 'CCCc1ccc(C(N)=O)cc1', 'CC(N)=O', 'CCCc1ccc(C(=O)NCC)cc1', 'CC(=O)NCCNC=O', 'CCCc1ccccc1', 'CCC', 'CC(=O)NCCNC(=O)c1ccccc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.