['COc1cc(CN)ccn1', 'CC(C)C(=O)NCCNC=O', 'CC(C)C(=O)NCCN', 'COc1cc(CNC=O)ccn1', 'CC(C)C=O', 'COc1cc(CNC(=O)NCCN)ccn1', 'CO', 'CC(C)C(=O)NCCNC(=O)NCc1ccncc1', 'COc1cc(C)ccn1', 'CC(C)C(=O)NCCNC(N)=O', 'CCNC(=O)C(C)C', 'COc1cc(CNC(N)=O)ccn1', 'CC(C)C(N)=O', 'CCNC(=O)NCc1ccnc(OC)c1', 'COc1ccccn1', 'CNC(=O)NCCNC(=O)C(C)C']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccncc1.