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