['CC(C)C', 'Nc1nnc(SCCO)s1', 'CC(C)(C)O', 'CCSc1nnc(N)s1', 'CCOC(C)(C)C', 'Nc1nnc(S)s1', 'Nc1nncs1', 'CC(C)(C)OCCS']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1nncs1.