['CCOCC(C)N', 'O=Cc1ccc([N+](=O)[O-])cc1Cl', 'CC', 'CC(CO)NC(=O)c1ccc([N+](=O)[O-])cc1Cl', 'CCO', 'CC(C)NC(=O)c1ccc([N+](=O)[O-])cc1Cl', 'CCCOCC', 'NC(=O)c1ccc([N+](=O)[O-])cc1Cl', 'CCOCC(C)NC=O', 'O=[N+]([O-])c1cccc(Cl)c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.