['C=CCN', 'CCN(CC=O)C(C)c1cc2ccccc2o1', 'C=CC', 'CCN(CC(N)=O)C(C)c1cc2ccccc2o1', 'C=CCNC(C)=O', 'CCNC(C)c1cc2ccccc2o1', 'CC', 'C=CCNC(=O)CNC(C)c1cc2ccccc2o1', 'C=CCNC(=O)CNCC', 'CCc1cc2ccccc2o1', 'c1ccc2occc2c1', 'C=CCNC(=O)CN(CC)CC']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2occc2c1.