['Cn1ccs/c1=N/C=O', 'Cc1csc(-c2ccccc2)n1', 'c1ccccc1', 'Cc1ncsc1C(=O)/N=c1/sccn1C']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(/N=c1\[nH]ccs1)c1cnc(-c2ccccc2)s1.