['CO', 'CN(CC=O)CCC(=O)NC1CC1', 'NC1CC1', 'COC(=O)CN(C)CCC=O', 'COC(C)=O', 'CNCCC(=O)NC1CC1', 'CNCC(=O)OC', 'CCC(=O)NC1CC1', 'C1CC1', 'COC(=O)CN(C)CCC(N)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C1CC1.