['CS(N)(=O)=O', 'CCCn1nc(C)c([N+](=O)[O-])c1C', 'C[SH](=O)=O', 'Cc1nn(CCCN)c(C)c1[N+](=O)[O-]', 'CCCNS(C)(=O)=O', 'Cc1n[nH]c(C)c1[N+](=O)[O-]']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cn[nH]c1.