['CO', 'Cc1sc2nc(CCC(=O)NC(C=O)CC(C)C)[nH]c(=O)c2c1C', 'COC(=O)C(N)CC(C)C', 'Cc1sc2nc(CCC=O)[nH]c(=O)c2c1C', 'COC(=O)CCC(C)C', 'Cc1sc2nc(CCC(N)=O)[nH]c(=O)c2c1C', 'Cc1sc2nc[nH]c(=O)c2c1C', 'CCC(=O)NC(CC(C)C)C(=O)OC']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=c1[nH]cnc2sccc12.