['CCN1CCOC1=O', 'O=[N+]([O-])c1cccnc1S', 'O=C1NCCO1', 'CCSc1ncccc1[N+](=O)[O-]', 'O=C1OCCN1CCS', 'O=[N+]([O-])c1cccnc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C1OCCN1CCSc1ccccn1.