['CCO', 'C[C@@]1(C=O)Oc2cc(Cl)ccc2NC1=O', 'CC', 'C[C@@]1(C(=O)O)Oc2cc(Cl)ccc2NC1=O', 'CCOC=O', 'C[C@@H]1Oc2cc(Cl)ccc2NC1=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C1COc2ccccc2N1.