['NC1CCS(=O)(=O)C1', 'C=CCNC(=S)NNC=O', 'C=CC', 'NC(=S)NNC(=O)NC1CCS(=O)(=O)C1', 'O=S1(=O)CCCC1', 'C=CCNC(=S)NNC(N)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=S1(=O)CCCC1.