['CO', 'O=CCn1c(-c2ccccc2)c[nH]c1=S', 'COC(C)=O', 'S=c1[nH]cc(-c2ccccc2)[nH]1', 'c1ccccc1', 'COC(=O)Cn1cc[nH]c1=S']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is S=c1[nH]cc(-c2ccccc2)[nH]1.