Abstract
2, 5-Diketo-D-gluconate (I) (D-threo-2, 5-hexodiulosonate) reacted with mono substituted hydrazines yielding anhydro 1-substituted 3-hydroxymethyl-5-hydroxypyridazinium hydroxides (IIa-g) which were a type of zwitterionic heterocyclic compounds, relatively unknown. Their structures were confirmed by their microanalytical results and spectroscopic evidences. The intermediate in the formation of anhydro 3-hydroxymethyl-5-hydroxy-1-phenyl-pyridazinium hydroxide was obtained. The structure (VIIc) (tautomeric 5-phenylhydrazone of 4-deoxy-2, 5-hexodiulosonate-3-ene) could be substantiated by spectral data. The formation of IIa-g might be accounted for in terms of mono phenylhydrazone formation, enediol formation, β-hydroxycarbonyl elimination, decarboxylation and cyclization.
