الفهرس 
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Abstract
This thesis includes three chapters; the first of which is a survey of the literature dealing with the synthesis of heterocycles from ascorbic acids.
Chapter II is a discussion of the work carried out by the candidate. The objectives of the work were discussed. The utility as well as the role of ascorbic acids in constructing the skeleton of the heterocyclic compounds were investigated. The carbon frame of the synthesised heterocycles belongs to the ascorbic acid precursor whereas the nitrogen atoms belong to either a hydrazine or a diamine molecule. Thus, a number of the bishydrazones was prepared, and in most cases two forms could be isolated. The difference between the two forms was due to the difference in the geometry of the two hydrazone residues. The rational for the possible mechanism of their interconversion was dis- cussed. The 1,4-lactone ring structure of the bis- hydrazones was confirmed.
When the bis(arylhydrazones) of I-threo-2,3- hexodiulosono-1,4-lactone and its D-epimer were heated with an ethanolic solution of cupric chloride, a yellow product could be isolated and formulated as 3,6-anhydro-3-(arylazo)-L-xylo-2-hexulosono-1,4-lactone.