['CO', 'CCCn1c(SCC(=O)C(C)(C)C)n[nH]c1=O', 'CC(=O)C(C)(C)C', 'COCCCn1c(S)n[nH]c1=O', 'CCCOC', 'CC(C)(C)C(=O)CSc1n[nH]c(=O)[nH]1', 'CC(C)(C)C(=O)CS', 'COCCCn1cn[nH]c1=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=c1[nH]cn[nH]1.