['O=CCCl', 'Nc1nnc(-c2ccc(F)cc2)s1', 'NC(=O)CCl', 'Fc1ccc(-c2nncs2)cc1', 'Fc1ccccc1', 'O=C(CCl)Nc1nncs1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(-c2nncs2)cc1.