['NC=O', 'NC(=O)CN1CCCSc2ccccc21', 'NC(N)=O', 'O=CCN1CCCSc2ccccc21', 'CC(=O)NC(N)=O', 'c1ccc2c(c1)NCCCS2']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2c(c1)NCCCS2.