['CNC(C)C', 'O=CN1C2CCC1c1ccccc12', 'CC(C)N(C)C=O', 'c1ccc2c(c1)C1CCC2N1', 'CCC', 'CNC(=O)N1C2CCC1c1ccccc12']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2c(c1)C1CCC2N1.