['COCCOCCN', 'Nc1ccc(C=O)cc1[N+](=O)[O-]', 'CO', 'CCOCCNC(=O)c1ccc(N)c([N+](=O)[O-])c1', 'CCOC', 'Nc1ccc(C(=O)NCCO)cc1[N+](=O)[O-]', 'COCCO', 'CCNC(=O)c1ccc(N)c([N+](=O)[O-])c1', 'CCOCCOC', 'NC(=O)c1ccc(N)c([N+](=O)[O-])c1', 'COCCOCCNC=O', 'Nc1ccccc1[N+](=O)[O-]']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.