['CC(C)(C)CC=O', 'Cn1ccnc1C(O)(CCN)C(F)(F)F', 'CC(C)(C)CC(N)=O', 'CCC(O)(c1nccn1C)C(F)(F)F', 'Cn1ccnc1', 'CC(C)(C)CC(=O)NCCC(O)C(F)(F)F']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1c[nH]cn1.