['CCN', 'CN(C=O)C1CCC(C)(C)C1', 'CCNC=O', 'CNC1CCC(C)(C)C1', 'CC', 'CN(C(N)=O)C1CCC(C)(C)C1', 'CCNC(=O)NC', 'CC1(C)CCCC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C1CCCC1.