['CN', 'O=CNCC1CCC2(CCOCC2)C1O', 'CNC=O', 'NCC1CCC2(CCOCC2)C1O', 'CNC(N)=O', 'CC1CCC2(CCOCC2)C1O', 'CNC(=O)NC', 'OC1CCCC12CCOCC2']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C1CCC2(C1)CCOCC2.