['CC(C)(C)N', 'COCCN[C@@H](C)C=O', 'CO', 'CCN[C@@H](C)C(=O)NC(C)(C)C', 'CCOC', 'C[C@H](N)C(=O)NC(C)(C)C', 'COCCN', 'CCC(=O)NC(C)(C)C', 'CC(C)C', 'COCCN[C@@H](C)C(N)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is None.