['CN', 'C[C@@H](Sc1ncc2ccccn12)C(=O)NC=O', 'CNC=O', 'C[C@@H](Sc1ncc2ccccn12)C(N)=O', 'CNC(N)=O', 'C[C@H](C=O)Sc1ncc2ccccn12', 'CCC(=O)NC(=O)NC', 'Sc1ncc2ccccn12', 'c1ccn2cncc2c1', 'CNC(=O)NC(=O)[C@@H](C)S']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccn2cncc2c1.