['COCCOCC=O', 'NC1CCN(C2CC2)C1', 'CO', 'CCOCC(=O)NC1CCN(C2CC2)C1', 'CCOC', 'O=C(CO)NC1CCN(C2CC2)C1', 'COCCO', 'CC(=O)NC1CCN(C2CC2)C1', 'C1CCN(C2CC2)C1', 'COCCOCC(N)=O', 'C1CC1', 'COCCOCC(=O)NC1CCNC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C1CCN(C2CC2)C1.