['CC(C)C', 'CN(N)c1nc(N)nc(N2CCOCC2)n1', 'CC(C)(C)N', 'CN(N)c1ncnc(N2CCOCC2)n1', 'C1COCCN1', 'CN(N)c1ncnc(NC(C)(C)C)n1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ncnc(N2CCOCC2)n1.