['CCn1cccn1', 'CS(=O)(=O)N1CCNCC1', 'C[SH](=O)=O', 'c1cnn(CCN2CCNCC2)c1', 'c1cn[nH]c1', 'CCN1CCN(S(C)(=O)=O)CC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cnn(CCN2CCNCC2)c1.