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