['NC(N)=O', 'CN(CC=O)Cc1ccccc1F', 'NC=O', 'CN(CC(N)=O)Cc1ccccc1F', 'CC(=O)NC(N)=O', 'CNCc1ccccc1F', 'Cc1ccccc1F', 'CNCC(=O)NC(N)=O', 'Fc1ccccc1', 'CN(C)CC(=O)NC(N)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.