Action of Halogens on Simple Carbohydrates

The non-aqueous oxidation of various ketones and aldehydes to hydroxyaldehydes and hydroxy ketones has been carried out in two steps the first step is a bromination and the second a hydrolysis, or replacement of the bromine atoms by hydroxyl groups. Fischer and Landsteiner brominated acetal in the presence of calcium carbonate (reaction 20). The bromoaldehyde Avas then treated with cold barium hydroxide solution (reaction 21) the resulting glycolic aldehyde was identified by conversion to glyoxal phenylosazone (reaction 22) and by the formation of calcium glycolate, after oxidation with bromine (reaction 23). 

CH(OCjH,)j -1- Br - BrCHjCHCOCjH.), -f HBr BrCH,CH(OC2H.), + 3HjO HOCHjCHO + HBr + 2CjHiOH 

Addition of bromine to a double bond has been observed in several cases. The hydrolysis of the resulting dibromide leads to a substance which may be regarded as an oxidation product of the original unsaturated compound. Fischer and Dangschat prepared glycolic aldehyde triacetate by the action of bromine on vinyl acetate and treatment of the resulting dibromide with acetic acid. 

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