RUFF-FENTON Degradation

RUFF - FENTON Degradation Oxidative degradation of aldoses via a-hydroxy acids to lower chain aldoses. 

RUFF FENTON Degradation 327 RUPE Rearrangement 328 RUZICKA FUKUSHIMA Rearrangement 3 Rylander 97... 

Ruff-Fenton degradation. Shortening of the carbon chain of sugars by the oxidation of aldonic acids (as calcium salts) with hydrogen peroxide and ferric salts. 

Robinson Annulation Robinson-Schopf Reaction Rosenmund Reduction Rosenmund-von Braun Synthesis Rothemund Reaction Rubottom Oxidation Ruff-Fenton Degradation Rupe Rearrangement Ruzicka Large Ring Synthesis Sabatier-Senderens Reduction Sachs (see Ehrlich-Sachs Reaction)... 

The well-known Ruff degradation of aldonic acids to aldoses with one less carbon was first applied with bromine as the oxidant. Calcium D-gluconate was treated with an excess of bromine at 20° for ten hours the acidity of the solution was kept low with lead carbonate. The filtrate was processed and D-arabinose was obtained in small yield as the oxime. However, Ruff found that the effect of hydrogen peroxide was much better and abandoned the use of bromine. Fenton noted the same effect in the oxidation of tartaric acid to dihydroxymaleic acid the action of oxygen was more effective than that of the halogens. It was assumed that a keto aldonic acid was the intermediate in the degradation of the aldonic acid to the new aldose, and the apparent stability of the keto acids to further oxidation by bromine may be the reason for the low yields with this oxidant. 

The conversion of a-hydroxy acids into aldehydes with one less carbon has great importance in the chemistry of sugars. Oxidation with bromine water transforms aldoses into the corresponding aldonic acids, which, in the form of their calcium salts, are treated with aqueous hydrogen peroxide in the presence of ferrous or ferric sulfate (Fenton reagent) and are degraded to aldoses with one less carbon (Ruff degradation) (equation 479) [57]. 

The Ruff degradation, in its classical version, conversion of the calcium salt of an aldonic acid to the aldose of one fewer carbon atoms by treatment with Fe and hydrogen peroxide, was one of the reactions used by Emil Fischer in his determination of the structure of the aldoses. Its success with Fe is mysterious, as one would expect Fenton chemistry involving HO to give molecular rubble, rather than good yields of a single product. However, the reaction is catalysed by transition metals in general (even with... 

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