['CS(N)(=O)=O', 'CCCN1C(=O)c2ccccc2C1=O', 'C[SH](=O)=O', 'NCCCN1C(=O)c2ccccc2C1=O', 'CCCNS(C)(=O)=O', 'O=C1NC(=O)c2ccccc21']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C1NC(=O)c2ccccc21.