['CC(C)(C)O', 'CCC(CC)c1nnc(NC(=O)CCNC=O)s1', 'CCC(CC)c1nnc(N)s1', 'CC(C)(C)OC(=O)NCCC=O', 'CC(C)(C)OC=O', 'CCC(CC)c1nnc(NC(=O)CCN)s1', 'CC(C)C', 'CCC(CC)c1nnc(NC(=O)CCNC(=O)O)s1', 'CC(C)(C)OC(N)=O', 'CCC(=O)Nc1nnc(C(CC)CC)s1', 'CCC(CC)c1nncs1', 'CC(C)(C)OC(=O)NCCC(N)=O', 'CCCCC', 'CC(C)(C)OC(=O)NCCC(=O)Nc1nncs1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1nncs1.