['CCC(=O)O', 'Cn1nnnc1-c1ccc(O)cc1', 'C[C@H](O)C(=O)O', 'Cn1nnnc1-c1ccccc1', 'Cn1cnnn1', 'C[C@H](Oc1ccccc1)C(=O)O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(-c2nnn[nH]2)cc1.