['COCC=O', 'CCCCCCNCCN1CCOCC1', 'CO', 'CCCCCCN(CCN1CCOCC1)C(C)=O', 'CCCCCC', 'COCC(=O)NCCN1CCOCC1', 'CCN1CCOCC1', 'CCCCCCNC(=O)COC', 'C1COCCN1', 'CCCCCCN(CC)C(=O)COC']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C1COCCN1.