['CC(C)COCCCN', 'O=CNNC(=O)c1cnccn1', 'CC(C)C', 'O=C(NCCCO)NNC(=O)c1cnccn1', 'CC(C)CO', 'CCCNC(=O)NNC(=O)c1cnccn1', 'CCCOCC(C)C', 'NC(=O)NNC(=O)c1cnccn1', 'c1cnccn1', 'CC(C)COCCCNC(=O)NNC=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cnccn1.