Inhibitors of shikimate dehydrogenase as potential herbicides.

The shikimic acid biosynthetic pathway, which operates in micro-organisms and higher plants but not in mammals, leads to several essential amino acids and also to a variety of other metabolites. It was hoped, therefore, that blockage of the pathway might have a damaging effect on plant metabolism, giving a useful commercial herbicide with selective toxicity. Shikimate dehydrogenase, the enzyme which catalyses the conversion of dehydroshikimate (I) to shikimate (11), was chosen as the target for inhibition because it occurs early in the pathway and because of the accessibility of synthetic substrate analogues.