Polyhydroxy acids, periodic acid oxidation

Most of the compounds that had been reported (before March, 1942) to show cleavage oxidation by periodic acid are recorded in the table the substances are listed alphabetically in the following groups of related compounds (1) carbocyclic compounds (2) carbohydrates (3) a-diketones and a-ketols (4) hydroxyamino compounds (5) polyhydroxy and hydroxyketo acids (6) polyhydroxy alcohols (7) steroids (8) miscellaneous compounds. French journals after May, 1940, and the majority of other foreign publications after June, 1941, were unavailable for the survey. 

The polyhydroxy side chain of sialic acids is rapidly oxidized with periodic acid to the corresponding C7-aldehyde. This aldehyde can be visualized with a number of Schiff and Schiff type reagents, substituted hydrazines, silver, etc. Of such procedures the most commonly employed is the periodic acid/Schiff technique (PAS) in which the Schiff reagent is prepared from basic fuchsin (Culling 1974). 

After the discovery by Malaprade 92) that polyhydroxy compounds were oxidized by periodate ion, Fleury and co-wOrkers 93) pointed out that the reaction is selective for hydroxyl groups on adjacent carbon atoms and results in chain scission. Hudson and co-workers 9Jf) developed periodate oxidation into an extremely convenient method for structural studies in carbohydrates 95). Because of the masking effect of the aglycon on the reducing carbon, the methyl glycosides are particularly suitable materials for this type of analysis. The method involves the determination of the molar ratios of oxidant consumed and of formic acid and formaldehyde produced. D-Mannitol, for example, consumes five moles of oxidant and produces four moles of formic acid and two moles of formaldehyde. 

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