Phenylhydrazine derivatives of sugars. Part I. Evidence for the cyclic structures of some sugar phenylhydrazones

Abstract

Infrared spectroscopic evidence suggests that the phenylhydrazones of D-galactose, D-glucose, and D-mannose are cyclic. This is contrary to the acyclic structures proposed on the basis of mild acetylation treatments and on their ability to yield formazan derivatives. Sugar phenylhydrazones previously shown to be cyclic by X-ray crystallography have been subjected to these treatments and acyclic products obtained, showing that these techniques are not valid methods for distinguishing between cyclic and acyclic structures.