['CO', 'NC(=O)CN(CCC=O)C1CCCC1', 'CCC(=O)OC', 'NC(=O)CNC1CCCC1', 'CC(N)=O', 'COC(=O)CCNC1CCCC1', 'C1CCCC1', 'COC(=O)CCNCC(N)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C1CCCC1.