['Cc1nncn1C', 'Nc1ccc([N+](=O)[O-])cn1', 'Cn1cnnc1CN', 'O=[N+]([O-])c1cccnc1', 'Cn1cnnc1', 'CNc1ccc([N+](=O)[O-])cn1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(NCc2nnc[nH]2)nc1.