['CO', 'Cc1c(C(=O)N(C)CC(C)C=O)cccc1[N+](=O)[O-]', 'CNCC(C)C(=O)OC', 'Cc1c(C=O)cccc1[N+](=O)[O-]', 'COC(=O)C(C)C', 'CNC(=O)c1cccc([N+](=O)[O-])c1C', 'Cc1ccccc1[N+](=O)[O-]', 'COC(=O)C(C)CN(C)C=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.