Degradation of 2-deoxyaldoses by alkaline hydrogen peroxide

Reaction of 2-deoxy-D-arabino-hexose, 2-deoxy-D-lyxo-hexose, and 2-deoxy-D-erythro-pentose with alkaline hydrogen peroxide in the presence of magnesium hydroxide afforded the corresponding 2-deoxyaldonic acid, the 1,4-lactone, and the 1-O-formyl derivative of the next lower alditol. The 2-deoxyaldonic acids were separated in 60–80% yields, as new, crystalline lithium salts. The 1,4-lactones were obtained under conditions that precluded intermidiate formation of the free acids: presumably, the reaction proceeded by way of an intermediate, furanosyl hydroperoxide, which was converted into the lactone by elimination of water. With an excess of alkaline hydrogen peroxide, in the absence of magnesium hydroxide, the substrates were degraded to formic acid, with concurrent decomposition of hydrogen peroxide. It is shown that decomposition of hydrogen peroxide is catalyzed by hydroperoxide anion, and that it takes place by both a chain, and a non-chain, process. The decomposition reactions afford an abundant source of hydroxyl radical capable of oxidizing a wide variety of compounds.