['CN', 'C[C@@H](C=O)Sc1nc2ccccc2[nH]1', 'CCC(=O)NC', 'Sc1nc2ccccc2[nH]1', 'CNC(=O)[C@H](C)S', 'c1ccc2[nH]cnc2c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2[nH]cnc2c1.