['CO', 'C[C@H]1Cc2[nH]c(=S)n(-c3ccccc3)c(=O)c2S1', 'COc1ccccc1', 'C[C@H]1Cc2[nH]c(=S)[nH]c(=O)c2S1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=c1c2c([nH]c(=S)n1-c1ccccc1)CCS2.