['COCCOCCN', 'O=Cc1ccc([N+](=O)[O-])cc1Cl', 'CO', 'CCOCCNC(=O)c1ccc([N+](=O)[O-])cc1Cl', 'CCOC', 'O=C(NCCO)c1ccc([N+](=O)[O-])cc1Cl', 'COCCO', 'CCNC(=O)c1ccc([N+](=O)[O-])cc1Cl', 'CCOCCOC', 'NC(=O)c1ccc([N+](=O)[O-])cc1Cl', 'COCCOCCNC=O', 'O=[N+]([O-])c1cccc(Cl)c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.