['NC(=O)NCC=O', 'CC1CCC(CN)CC1', 'NC=O', 'CC1CCC(CNC(=O)CN)CC1', 'CC1CCC(C)CC1', 'NC(=O)CNC(N)=O', 'NC(N)=O', 'CC(=O)NCC1CCC(C)CC1', 'CC1CCCCC1', 'CNC(=O)CNC(N)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C1CCCCC1.