['CO', 'NC(=O)NC1CCC(C=O)CC1', 'NC=O', 'COC(=O)C1CCC(N)CC1', 'NC(N)=O', 'COC(=O)C1CCCCC1', 'COC=O', 'NC(=O)NC1CCCCC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C1CCCCC1.