['NC(N)=O', 'C[C@H](NCC=O)c1ccc(Cl)cc1', 'NC=O', 'C[C@H](NCC(N)=O)c1ccc(Cl)cc1', 'NCC(=O)NC(N)=O', 'CCc1ccc(Cl)cc1', 'CC(=O)NC(N)=O', 'C[C@H](N)c1ccc(Cl)cc1', 'Clc1ccccc1', 'CCNCC(=O)NC(N)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.