['C[C@@H]1CNC[C@H](C)O1', 'CC(=O)c1cc(C)n(C)c1C', 'Cc1ccc(C)n1C', 'C[C@@H]1CN(CC=O)C[C@H](C)O1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(CN1CCOCC1)c1cc[nH]c1.