Early studies on the biosynthesis of the quinoline quinone portion of
streptonigrin, 1, had suggested the intermediacy of novel aromatic amino
acids. In order to test this hypothesis, a series of compounds was synthesized
and tested for potential incorporation. [4-¹⁵N] 4-Aminoanthranilic acid,
4 5 a , [4-² H] 7-aminoquinaldinic acid,...