Alditols catalytic oxidation

The catalytic hydrogenation of nitro alcohol to amino alcohol has been applied to the synthesis of an intermediate leading to sugar alcohols. The condensation of ni-tromethane with pentoses in the presence of sodium methoxide, followed by hydrogenation over platinum oxide and deamination with nitric acid, gave the alditols with one more carbon atom.22 The reaction sequence is as follows pentose — 2-epimeric sodio aci-nitro alcohols —> 2-epimeric hexitylamines —> 2-epimeric hexitols + 2-epi-meric 1,4-anhydrohexitols. The 2-epimeric sodio a -nitro alcohols were hydrogenated to 2-epimeric hexitylamines over platinum oxide in acetic acid. An example is shown in eq. 9.8 with D-ribose. 

Aldoses and alditols can be rapidly oxidized by hydrogen peroxide under certain conditions leading to the formation of formic acid with evolution of oxygen, and a mechanism was proposed involving catalysis by superoxide radicals generated from traces of transition metal salts in Fenton s reaction ferrous ion is considered to play an analogous catalytic role. ... 

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