['CC', 'N#Cc1cc([N+](=O)[O-])c(N2CCNCC2)c([N+](=O)[O-])c1', 'CCN1CCNCC1', 'N#Cc1cc([N+](=O)[O-])cc([N+](=O)[O-])c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(N2CCNCC2)cc1.