The 2, 4, 7-trianiino-6-heteroarylpteridi1ies prepared as part of this research are listed in Table I along with their uv absorption data determined at pH 1 and pH 14. Inspection of these data shows that the compounds fall into several classes. In one class at pH 1 the long wavelength peak falls between 338 and 366 mp and at pH 14 between 364 and 374. In this class the 6-heterocyclic ring is attached to the pteridine either/3 to the heteroatom or via a ...
