['CN', 'C[C@@H](C(=O)NC=O)N1CCN(c2ccc([N+](=O)[O-])nc2)CC1', 'CNC=O', 'C[C@@H](C(N)=O)N1CCN(c2ccc([N+](=O)[O-])nc2)CC1', 'CNC(N)=O', 'C[C@@H](C=O)N1CCN(c2ccc([N+](=O)[O-])nc2)CC1', 'CCC(=O)NC(=O)NC', 'O=[N+]([O-])c1ccc(N2CCNCC2)cn1', 'O=[N+]([O-])c1ccccn1', 'CNC(=O)NC(=O)[C@H](C)N1CCNCC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cncc(N2CCNCC2)c1.