Oxidative decarboxilation of aldonolactones by ceric sulphate in aqueous sulphuric acid. Synthesis of D-arabinose

L. SALA; A. FERNÁNDEZ CIRELLI; R. MUCHNIK DE LEDERKREMER

Journal of Chemistry Society Perkin

The Royal Society of Chemistry

Lugar: Pekin; Año: 1977 vol. 2 p. 685 - 688

0300-9580

Oxidations of D-glucono-1,5-lactone, D-glucono-1,4-lactone, calcium D-gluconate, and 3-deoxy-D-arabino-hexono-1,4-lactone by cerium(IV) sulphate in sulphuric acid were studied at 25 and at 37 °C, with various concentrations of reactants and acidities. The results indicated that it is the aldonic acid that undergoes oxidation; the stoicheiometry requires two cerium(IV) ions for the oxidation of one molecule of aldonic acid to the next lower sugar. The rate of disappearance of cerium(IV) ions depended directly on its concentration, but the dependence on the organic substrate concentration suggested the existence of an intermediate complex; this was proved by a spectrophotometric method. The complex undergoes slow unimolecular decomposition to a free radical, which reacts with CeIV to afford the products. The reaction rate was proportional to 1/[SO4H2]2. A preparative experiment with D-glucono-1,5-lactone gave crystalline D-arabinose in 94% yield.