['C[SH](=O)=O', 'O=[N+]([O-])c1c(NC2CCCNC2)nc2sccn12', 'CS(=O)(=O)N1CCCC(N)C1', 'O=[N+]([O-])c1cnc2sccn12', 'CS(=O)(=O)N1CCCCC1', 'Nc1nc2sccn2c1[N+](=O)[O-]']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cn2cc(NC3CCCNC3)nc2s1.