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