Carbohydrate Hydrazones and Osazones as Organic Raw Materials for Nucleosides and Heterocycles

The synthetic potential of low molecular weight carbohydrates in the form of their hydrazones or bishydrazones as precursors for heterocyclic compounds and acyclic nucleosides, which could be degraded into functionalized heterocycles without polyol residues, is the subject of this review. The inherent functionalities in such hydrazone derivatives make them suitable for building the skeleton of heterocyclic compounds. This strategy also offers the possibility for the synthesis of heterocycles possessing chiral centers. This review covers the synthesis of various classes of heterocyclic compounds and their nucleoside analogues. Thus, ring system of type perhydro-furans and pyrans, pyrazoles, pyrazolines, isoxazolines, triazoles, oxadiazoles, oxadiazolines, thiadiazoles, thiadiazolines, tetrazoles, pyridazines, 1,2,4-triazines, as well as their condensed analogues (condensed azoles, pyrazoles, 1,2,3-triazoles, 1,2,4-triazoles, diazines, quinoxalines, and furans) can be prepared.