1 AOB (E)-2-amino-4-oxo-6-styryl-4,7-dihydro-3h-pyrrolo[2,3-D]pyrimidine-5-carbonitrile 1.000 2 IZ9 (E)-2,4-diamino-6-(4-methylstyryl)-7h-pyrrolo[2,3-D]pyrimidine-5-carbonitrile 0.870 3 87Y 7,8-dihydro-6-hydroxymethyl-7-methyl-7-[2-phenylethyl]-pterin 0.760