['Clc1ccccc1', 'O=[N+]([O-])c1cccc(-c2c[nH]c(=S)[nH]2)c1', 'O=[N+]([O-])c1ccccc1', 'S=c1[nH]ccn1-c1cccc(Cl)c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is S=c1[nH]cc(-c2ccccc2)n1-c1ccccc1.