['c1ccc2c(c1)OCCO2', 'O=CNNC(=O)c1ccc2ncsc2c1', 'c1ccc2scnc2c1', 'O=CNNC(=O)[C@@H]1COc2ccccc2O1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(NNC(=O)[C@@H]1COc2ccccc2O1)c1ccc2ncsc2c1.