['CC(C)(C)O', 'Cc1noc(C(=O)O)c1NC=O', 'CC(C)(C)OC=O', 'Cc1noc(C(=O)O)c1N', 'CC(C)C', 'Cc1noc(C(=O)O)c1NC(=O)O', 'CC(C)(C)OC(N)=O', 'Cc1cc(C(=O)O)on1', 'O=CO', 'Cc1nocc1NC(=O)OC(C)(C)C']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cnoc1.